Anyone using a low mass or lightweight AR bolt carrier? Research says it saves around 3 to 4 ounces of weight, makes their rifle cycle faster and have less recoil but it's also hard on brass. Any real world experience input will be appreciated.
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Re: Low Mass or Lightweight Bolt Carriers
I have the JP LMOS carrier and lightweight buffer in my one build its worked great for me. I have an adjustable gas system on the rifle so its probably not as hard on brass, but Ive had no problems with it being hard on brass I reload all of my brass and some of my brass is going on 10 loadings now. I just wanted them for less recoil.
I have the JP LMOS carrier and lightweight buffer in my one build its worked great for me. I have an adjustable gas system on the rifle so its probably not as hard on brass, but Ive had no problems with it being hard on brass I reload all of my brass and some of my brass is going on 10 loadings now. I just wanted them for less recoil.
Re: Low Mass or Lightweight Bolt Carriers
A lighter BCG will cause heavier felt recoil if all else is held constant. You will find many people will try to run the heaviest buffer possible to reduce felt recoil and delay bolt unlock. There are alot of places I would look to cut weight before the BCG. As the poster before mentioned they work well with adjustable gas systems.
A lighter BCG will cause heavier felt recoil if all else is held constant. You will find many people will try to run the heaviest buffer possible to reduce felt recoil and delay bolt unlock. There are alot of places I would look to cut weight before the BCG. As the poster before mentioned they work well with adjustable gas systems.
Re: Low Mass or Lightweight Bolt Carriers
i would think a heavy buffer would defeat the purpose of a light carrier. maybe i'm missing something
i have a game gun with jp low mass (aluminum) BC and FCG and adjustable gas (17" bbl with rifle gas) and enidine pneumatic buffer. the combo works fantastic.
i shot ~1500 rnds through it with no problems (once i got it adjusted) however, some friends had an issue where the gas rings wore the inside of the carrier prematurely. set my expectations that the aluminum carrier was a "wear part" which is ok if you know before you buy. taht was a few years ago though. product may have changed
i would think a heavy buffer would defeat the purpose of a light carrier. maybe i'm missing something
i have a game gun with jp low mass (aluminum) BC and FCG and adjustable gas (17" bbl with rifle gas) and enidine pneumatic buffer. the combo works fantastic.
i shot ~1500 rnds through it with no problems (once i got it adjusted) however, some friends had an issue where the gas rings wore the inside of the carrier prematurely. set my expectations that the aluminum carrier was a "wear part" which is ok if you know before you buy. taht was a few years ago though. product may have changed
Re: Low Mass or Lightweight Bolt Carriers
What is the rifle going to be used for ?
As part of a set of components on a competition rifle they work well after tuning to the load . In a self defense/duty rifle its not recommend .
What is the rifle going to be used for ?
As part of a set of components on a competition rifle they work well after tuning to the load . In a self defense/duty rifle its not recommend .
Re: Low Mass or Lightweight Bolt Carriers
The lighter carrier and buffer reduces felt recoil and muzzle rise. It's a basic physics problem of torque.
If you're trying to tighten a bolt, you can either do one of two things. Increase the amount of force on the wrench or extend the length of the wrench.
On an AR, the distance from the hand to the carrier (wrench arm) is relatively fixed. So...to reduce the amount of muzzle rise (torque) you need to reduce the force. Force being mass x acceleration, we drop the weight of the carrier and buffer (the moving parts that equate to the force).
So...now what about the carrier moving faster due to being lighter? Doesn't it moving faster make up for the amount of weight lost? Not really. The amount of gas driving the carrier is the same whether there is a carrier there or not. However, all things being equal, the carrier will move faster but the increased speed is less than the weight lost. The bigger problem is out cycling the magazine and not picking up a round. Doesn't happen all the time, but can happen.
How do we fix this? Adjustable gas systems. You can increase or retard the amount of gas as necessary for your load. The end result is a rifle that feels like a 22 and cycles very fast and stays on target.
Rich
The lighter carrier and buffer reduces felt recoil and muzzle rise. It's a basic physics problem of torque.
If you're trying to tighten a bolt, you can either do one of two things. Increase the amount of force on the wrench or extend the length of the wrench.
On an AR, the distance from the hand to the carrier (wrench arm) is relatively fixed. So...to reduce the amount of muzzle rise (torque) you need to reduce the force. Force being mass x acceleration, we drop the weight of the carrier and buffer (the moving parts that equate to the force).
So...now what about the carrier moving faster due to being lighter? Doesn't it moving faster make up for the amount of weight lost? Not really. The amount of gas driving the carrier is the same whether there is a carrier there or not. However, all things being equal, the carrier will move faster but the increased speed is less than the weight lost. The bigger problem is out cycling the magazine and not picking up a round. Doesn't happen all the time, but can happen.
How do we fix this? Adjustable gas systems. You can increase or retard the amount of gas as necessary for your load. The end result is a rifle that feels like a 22 and cycles very fast and stays on target.
Rich
Re: Low Mass or Lightweight Bolt Carriers
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">A lighter BCG will cause heavier felt recoil if all else is held constant. </div></div>
False....
Us 3Gunners who are interesting in shooting as fast as we can with a desired sight picture often use either stock or lightened reciprocating mass systems in the AR. This can range from a full JP LMOS which includes the carrier and buffer, or just a lighter carrier. I use a RLGS on a 17" with full gas, but the lightened Young Mfg bolt carrier. Less moving mass keeps the sight picture on target better and yes reduces felt recoil.
http://demigodllc.com/articles/evolution-of-the-3-gun-practical-rifle/
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
The last aspect to recoil management involves tuning the reciprocating mass and springs that comprise the rifle action. In the AR-15, the bolt carrier group (BCG) and recoil buffer move rearward until they bottom out in the receiver extension tube. As they bounce and change direction, they impart additional rearward momentum to the rifle. Next, they return forward, strip the next round from the magazine, and then slam into battery causing muzzle dip. By reducing the total reciprocating mass, the inertia effects of these secondary recoil impulses can be reduced. This shortens the action's cycle time and increases BCG speed. With this change, not only is the action finished operating and ready to fire again sooner, but many 3-Gun shooters perceive a faster-cycling action as causing less sight-picture movement. </div></div>
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">A lighter BCG will cause heavier felt recoil if all else is held constant. </div></div>
False....
Us 3Gunners who are interesting in shooting as fast as we can with a desired sight picture often use either stock or lightened reciprocating mass systems in the AR. This can range from a full JP LMOS which includes the carrier and buffer, or just a lighter carrier. I use a RLGS on a 17" with full gas, but the lightened Young Mfg bolt carrier. Less moving mass keeps the sight picture on target better and yes reduces felt recoil.
http://demigodllc.com/articles/evolution-of-the-3-gun-practical-rifle/
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
The last aspect to recoil management involves tuning the reciprocating mass and springs that comprise the rifle action. In the AR-15, the bolt carrier group (BCG) and recoil buffer move rearward until they bottom out in the receiver extension tube. As they bounce and change direction, they impart additional rearward momentum to the rifle. Next, they return forward, strip the next round from the magazine, and then slam into battery causing muzzle dip. By reducing the total reciprocating mass, the inertia effects of these secondary recoil impulses can be reduced. This shortens the action's cycle time and increases BCG speed. With this change, not only is the action finished operating and ready to fire again sooner, but many 3-Gun shooters perceive a faster-cycling action as causing less sight-picture movement. </div></div>
Re: Low Mass or Lightweight Bolt Carriers
How do hot loads a Light carriers work out in an AR10 ?
How do hot loads a Light carriers work out in an AR10 ?
Re: Low Mass or Lightweight Bolt Carriers
With the rifle I described above, I've run a gazillion M193 and hot 77's through it no problem. When I had my JP rifle with the original aluminum LMOS bolt carrier, I shot the same and had no problems due to the ammo.
With the rifle I described above, I've run a gazillion M193 and hot 77's through it no problem. When I had my JP rifle with the original aluminum LMOS bolt carrier, I shot the same and had no problems due to the ammo.
Re: Low Mass or Lightweight Bolt Carriers
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Zak Smith</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">A lighter BCG will cause heavier felt recoil if all else is held constant. </div></div>
False....
Us 3Gunners who are interesting in shooting as fast as we can with a desired sight picture often use either stock or lightened reciprocating mass systems in the AR. This can range from a full JP LMOS which includes the carrier and buffer, or just a lighter carrier. I use a RLGS on a 17" with full gas, but the lightened Young Mfg bolt carrier. Less moving mass keeps the sight picture on target better and yes reduces felt recoil.
http://demigodllc.com/articles/evolution-of-the-3-gun-practical-rifle/
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
The last aspect to recoil management involves tuning the reciprocating mass and springs that comprise the rifle action. In the AR-15, the bolt carrier group (BCG) and recoil buffer move rearward until they bottom out in the receiver extension tube. As they bounce and change direction, they impart additional rearward momentum to the rifle. Next, they return forward, strip the next round from the magazine, and then slam into battery causing muzzle dip. By reducing the total reciprocating mass, the inertia effects of these secondary recoil impulses can be reduced. This shortens the action's cycle time and increases BCG speed. With this change, not only is the action finished operating and ready to fire again sooner, but many 3-Gun shooters perceive a faster-cycling action as causing less sight-picture movement. </div></div>
</div></div>
I am sorry for spreading misinformation if that is the case. I always thought that the lighter carrier/buffer without a restriction of the gas system or softer shooting ammo would cause increased recoil. I always assumed that the 3gun setups had lighter recoil because of restriction of the gas (either by adjustable setup or smaller than typical gasport). I have never experienced a gun with lightened carrier/buffer that did not have a modified gas system.
Thinking out loud: Has anyone ever shot an AR that is overgassed (oversized gasport) with a normal buffer and carrier. The recoil is very sharp compared to a properly gassed AR. Then take that overgassed gun and add a heavy carrier/buffer and recoil feels less. Why does this affect not translate to a normally gassed AR with a lighter carrier/buffer?
ETA - Still I think my original point is valid. To lighten a gun there are alot of places to do it before messing with a lighter carrier.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Zak Smith</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">A lighter BCG will cause heavier felt recoil if all else is held constant. </div></div>
False....
Us 3Gunners who are interesting in shooting as fast as we can with a desired sight picture often use either stock or lightened reciprocating mass systems in the AR. This can range from a full JP LMOS which includes the carrier and buffer, or just a lighter carrier. I use a RLGS on a 17" with full gas, but the lightened Young Mfg bolt carrier. Less moving mass keeps the sight picture on target better and yes reduces felt recoil.
http://demigodllc.com/articles/evolution-of-the-3-gun-practical-rifle/
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
The last aspect to recoil management involves tuning the reciprocating mass and springs that comprise the rifle action. In the AR-15, the bolt carrier group (BCG) and recoil buffer move rearward until they bottom out in the receiver extension tube. As they bounce and change direction, they impart additional rearward momentum to the rifle. Next, they return forward, strip the next round from the magazine, and then slam into battery causing muzzle dip. By reducing the total reciprocating mass, the inertia effects of these secondary recoil impulses can be reduced. This shortens the action's cycle time and increases BCG speed. With this change, not only is the action finished operating and ready to fire again sooner, but many 3-Gun shooters perceive a faster-cycling action as causing less sight-picture movement. </div></div>
</div></div>
I am sorry for spreading misinformation if that is the case. I always thought that the lighter carrier/buffer without a restriction of the gas system or softer shooting ammo would cause increased recoil. I always assumed that the 3gun setups had lighter recoil because of restriction of the gas (either by adjustable setup or smaller than typical gasport). I have never experienced a gun with lightened carrier/buffer that did not have a modified gas system.
Thinking out loud: Has anyone ever shot an AR that is overgassed (oversized gasport) with a normal buffer and carrier. The recoil is very sharp compared to a properly gassed AR. Then take that overgassed gun and add a heavy carrier/buffer and recoil feels less. Why does this affect not translate to a normally gassed AR with a lighter carrier/buffer?
ETA - Still I think my original point is valid. To lighten a gun there are alot of places to do it before messing with a lighter carrier.
Re: Low Mass or Lightweight Bolt Carriers
How about with a CAN ?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Zak Smith</div><div class="ubbcode-body">With the rifle I described above, I've run a gazillion M193 and hot 77's through it no problem. When I had my JP rifle with the original aluminum LMOS bolt carrier, I shot the same and had no problems due to the ammo.
</div></div>
How about with a CAN ?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Zak Smith</div><div class="ubbcode-body">With the rifle I described above, I've run a gazillion M193 and hot 77's through it no problem. When I had my JP rifle with the original aluminum LMOS bolt carrier, I shot the same and had no problems due to the ammo.
</div></div>
Re: Low Mass or Lightweight Bolt Carriers
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ASM1</div><div class="ubbcode-body">How do hot loads a Light carriers work out in an AR10 ?</div></div>
My LR-308 with 150gr FMJ's at just shy of 3k with a carrier HEAVILY modified by Benny Hill at Triangle Shooting Sports runs like a scalded cat and feel like I'm shooting a non-compensated AR. So to say that it shoots flat and there's little felt recoil is an understatement.
Rich
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ASM1</div><div class="ubbcode-body">How do hot loads a Light carriers work out in an AR10 ?</div></div>
My LR-308 with 150gr FMJ's at just shy of 3k with a carrier HEAVILY modified by Benny Hill at Triangle Shooting Sports runs like a scalded cat and feel like I'm shooting a non-compensated AR. So to say that it shoots flat and there's little felt recoil is an understatement.
Rich
Re: Low Mass or Lightweight Bolt Carriers
What spring and buffer,are you useing ? AR15 m4 TUBE or 10 length tube?
I am throwing 150's from a 18" Noveske barrel 2900fps,I had no trouble without the Can,But I added the Can and it would overrun the spent case and shut on it before it could leave the rec. I added the Tubs carrier weight and it stopped doing that. I am useing the AR15 M4 tube and heavy buffer from the guy on ARFCOM.. <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: uscbigdawg</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ASM1</div><div class="ubbcode-body">How do hot loads a Light carriers work out in an AR10 ?</div></div>
My LR-308 with 150gr FMJ's at just shy of 3k with a carrier HEAVILY modified by Benny Hill at Triangle Shooting Sports runs like a scalded cat and feel like I'm shooting a non-compensated AR. So to say that it shoots flat and there's little felt recoil is an understatement.
Rich
</div></div>
What spring and buffer,are you useing ? AR15 m4 TUBE or 10 length tube?
I am throwing 150's from a 18" Noveske barrel 2900fps,I had no trouble without the Can,But I added the Can and it would overrun the spent case and shut on it before it could leave the rec. I added the Tubs carrier weight and it stopped doing that. I am useing the AR15 M4 tube and heavy buffer from the guy on ARFCOM.. <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: uscbigdawg</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ASM1</div><div class="ubbcode-body">How do hot loads a Light carriers work out in an AR10 ?</div></div>
My LR-308 with 150gr FMJ's at just shy of 3k with a carrier HEAVILY modified by Benny Hill at Triangle Shooting Sports runs like a scalded cat and feel like I'm shooting a non-compensated AR. So to say that it shoots flat and there's little felt recoil is an understatement.
Rich
</div></div>
Re: Low Mass or Lightweight Bolt Carriers
Added mass = Increased Dwell Time
Increased Dwell Time = longer period of time for gas pressure to equalize
(Effectively providing similar results as less gas.)
That is why felt recoil is often attributed to Heavy Buffers / BCG.
Light Bolt Carrier = Minimal Dwell Time & Minimal Reciprocating Mass
Minimal Dwell Time = Higher RPM
Higher RPM = Hard on Brass due to brass still being under pressure
Minimal Reciprocating Mass = Less Mass Transferred via Inertia
As an added note:
Heavy Buffers, Full Auto Bolt Carrier Groups, and Enhanced Action Springs are excellent ways to increase reliability by increasing the amount of force driving the action.
They also make suppressed firing of an AR a much more pleasant experience.
This occurs because the increased dwell time allows more gas to escape from the gun prior to the action cycling.
Three Gun Shooting is a different animal than defensive of combat use of a carbine.
In USPSA, you only have a bad match if your gun goes down.
The same can not be said for the latter…
When it comes to USPSA / Three Gun stuff, Zak Smith is a big player and is one your should listen to closely.
(He is also an ok guy...)
Added mass = Increased Dwell Time
Increased Dwell Time = longer period of time for gas pressure to equalize
(Effectively providing similar results as less gas.)
That is why felt recoil is often attributed to Heavy Buffers / BCG.
Light Bolt Carrier = Minimal Dwell Time & Minimal Reciprocating Mass
Minimal Dwell Time = Higher RPM
Higher RPM = Hard on Brass due to brass still being under pressure
Minimal Reciprocating Mass = Less Mass Transferred via Inertia
As an added note:
Heavy Buffers, Full Auto Bolt Carrier Groups, and Enhanced Action Springs are excellent ways to increase reliability by increasing the amount of force driving the action.
They also make suppressed firing of an AR a much more pleasant experience.
This occurs because the increased dwell time allows more gas to escape from the gun prior to the action cycling.
Three Gun Shooting is a different animal than defensive of combat use of a carbine.
In USPSA, you only have a bad match if your gun goes down.
The same can not be said for the latter…
When it comes to USPSA / Three Gun stuff, Zak Smith is a big player and is one your should listen to closely.
(He is also an ok guy...)
Re: Low Mass or Lightweight Bolt Carriers
You know your Kit,But I know you dont need my aproval...
I run LMT enhance 16 Carrier/Tubbs,weight,,In my mk12 18"/Rifle Gas now for 10,800 ROUNDS of MK262 or home built 75bthp, 50/50 with a Can..only issue was a Primer came out of a bad peace of brass and stuck in between the carrier skys and upper,stoped the weapon cold and had to take the rec,tube off and drive the carrier in with a dead blow hammer.. other than that total Bliss and the brass is in great condition and usable for many more loadings..
If I could get the AR10 to be as reliable and not beat up the brass I would be happy,I have a Noveske barrel 18" and wish it was a Rifle gas..I added the Tubs Weight,but I know its just on the edge without the can and in the red of reliability with the CAN. I need to back the load Down or find a way to vent more gas ?
Hijack over..
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dr. Phil</div><div class="ubbcode-body">Added mass = Increased Dwell Time
Increased Dwell Time = longer period of time for gas pressure to equalize
(Effectively providing similar results as less gas.)
That is why felt recoil is often attributed to Heavy Buffers / BCG.
Light Bolt Carrier = Minimal Dwell Time & Minimal Reciprocating Mass
Minimal Dwell Time = Higher RPM
Higher RPM = Hard on Brass due to brass still being under pressure
Minimal Reciprocating Mass = Less Mass Transferred via Inertia
As an added note:
Heavy Buffers, Full Auto Bolt Carrier Groups, and Enhanced Action Springs are excellent ways to increase reliability by increasing the amount of force driving the action.
They also make suppressed firing of an AR a much more pleasant experience.
This occurs because the increased dwell time allows more gas to escape from the gun prior to the action cycling.
Three Gun Shooting is a different animal than defensive of combat use of a carbine.
In USPSA, you only have a bad match if your gun goes down.
The same can not be said for the latter…
When it comes to USPSA / Three Gun stuff, Zak Smith is a big player and is one your should listen to closely.
(He is also an ok guy...) </div></div>
You know your Kit,But I know you dont need my aproval...
I run LMT enhance 16 Carrier/Tubbs,weight,,In my mk12 18"/Rifle Gas now for 10,800 ROUNDS of MK262 or home built 75bthp, 50/50 with a Can..only issue was a Primer came out of a bad peace of brass and stuck in between the carrier skys and upper,stoped the weapon cold and had to take the rec,tube off and drive the carrier in with a dead blow hammer.. other than that total Bliss and the brass is in great condition and usable for many more loadings..
If I could get the AR10 to be as reliable and not beat up the brass I would be happy,I have a Noveske barrel 18" and wish it was a Rifle gas..I added the Tubs Weight,but I know its just on the edge without the can and in the red of reliability with the CAN. I need to back the load Down or find a way to vent more gas ?
Hijack over..
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dr. Phil</div><div class="ubbcode-body">Added mass = Increased Dwell Time
Increased Dwell Time = longer period of time for gas pressure to equalize
(Effectively providing similar results as less gas.)
That is why felt recoil is often attributed to Heavy Buffers / BCG.
Light Bolt Carrier = Minimal Dwell Time & Minimal Reciprocating Mass
Minimal Dwell Time = Higher RPM
Higher RPM = Hard on Brass due to brass still being under pressure
Minimal Reciprocating Mass = Less Mass Transferred via Inertia
As an added note:
Heavy Buffers, Full Auto Bolt Carrier Groups, and Enhanced Action Springs are excellent ways to increase reliability by increasing the amount of force driving the action.
They also make suppressed firing of an AR a much more pleasant experience.
This occurs because the increased dwell time allows more gas to escape from the gun prior to the action cycling.
Three Gun Shooting is a different animal than defensive of combat use of a carbine.
In USPSA, you only have a bad match if your gun goes down.
The same can not be said for the latter…
When it comes to USPSA / Three Gun stuff, Zak Smith is a big player and is one your should listen to closely.
(He is also an ok guy...) </div></div>
Re: Low Mass or Lightweight Bolt Carriers
I guess I should have mentioned in the original question, this is a competition 6.8 SPC II. It will see mostly competition events, no actual self defense, and minimal hunting. Major objective is reducing total rifle weight to enhance speed of handling the weapon. I am also leaning toward the one from Young Manufacturing.
http://www.youngmanufacturing.net/product-info.php?pid102.html
I guess I should have mentioned in the original question, this is a competition 6.8 SPC II. It will see mostly competition events, no actual self defense, and minimal hunting. Major objective is reducing total rifle weight to enhance speed of handling the weapon. I am also leaning toward the one from Young Manufacturing.
http://www.youngmanufacturing.net/product-info.php?pid102.html
Re: Low Mass or Lightweight Bolt Carriers
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ASM1</div><div class="ubbcode-body">You know your Kit,But I know you dont need my aproval...
I run LMT enhance 16 Carrier/Tubbs,weight,,In my mk12 18"/Rifle Gas now for 10,800 ROUNDS of MK262 or home built 75bthp, 50/50 with a Can..only issue was a Primer came out of a bad peace of brass and stuck in between the carrier skys and upper,stoped the weapon cold and had to take the rec,tube off and drive the carrier in with a dead blow hammer.. other than that total Bliss and the brass is in great condition and usable for many more loadings..
If I could get the AR10 to be as reliable and not beat up the brass I would be happy,I have a Noveske barrel 18" and wish it was a Rifle gas..I added the Tubs Weight,but I know its just on the edge without the can and in the red of reliability with the CAN. I need to back the load Down or find a way to vent more gas ?
Hijack over.. </div></div>
I'm also a big fan of the LMT Enhanced Bolt Carrier Group.
That BCG has completely different timing to increase dwell time.
(The newer ones now have an additional small hole behind the three exhaust ports to help make them work better with short barrel setups.)
It's too bad that they don't have one for the 308 platform.
The AR platform in 308 is notorious for being way more difficult to get working as well or shooting as well as it's 5.56 NATO little brother.
I had a similar instance as you regarding a popped primer when I was doing 300 BLK load development.
I resolved it my "Pogo Sticking" the rifle until the primer gave way.
(Actually bent the locking pin on my SOPMOD stock.)
There are a few things that you can do to tweak your setup to stretch every last bit of performance out of your rifle:
- First is the one that you probably didn't want to hear, adjustable gas system.
By either modifying your gas block to be one, or purchasing one, you can do a lot more fine tuning.
If you are like me though, you are likely a bit wary of introducing anything that has the potential to fail and induce problems.
Adjustable gas systems that use threaded valves can and do move over time in such a harsh environment.
- Second is going to be Buffer Weight.
You said that you are using the JP weights, but there is Slashes Heavy Buffers as well.
http://www.heavybuffers.com/
His buffers are designed specifically for what you are doing.
(This is where I would start if I were you.)
- Third is going to be further load development.
If you choose a powder and charge weight by its burn rate and pressure characteristics you could find a load that better meets your goals.
(Albeit, at the cost of time, money, and aggravation.)
Hope this helps...
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ASM1</div><div class="ubbcode-body">You know your Kit,But I know you dont need my aproval...
I run LMT enhance 16 Carrier/Tubbs,weight,,In my mk12 18"/Rifle Gas now for 10,800 ROUNDS of MK262 or home built 75bthp, 50/50 with a Can..only issue was a Primer came out of a bad peace of brass and stuck in between the carrier skys and upper,stoped the weapon cold and had to take the rec,tube off and drive the carrier in with a dead blow hammer.. other than that total Bliss and the brass is in great condition and usable for many more loadings..
If I could get the AR10 to be as reliable and not beat up the brass I would be happy,I have a Noveske barrel 18" and wish it was a Rifle gas..I added the Tubs Weight,but I know its just on the edge without the can and in the red of reliability with the CAN. I need to back the load Down or find a way to vent more gas ?
Hijack over.. </div></div>
I'm also a big fan of the LMT Enhanced Bolt Carrier Group.
That BCG has completely different timing to increase dwell time.
(The newer ones now have an additional small hole behind the three exhaust ports to help make them work better with short barrel setups.)
It's too bad that they don't have one for the 308 platform.
The AR platform in 308 is notorious for being way more difficult to get working as well or shooting as well as it's 5.56 NATO little brother.
I had a similar instance as you regarding a popped primer when I was doing 300 BLK load development.
I resolved it my "Pogo Sticking" the rifle until the primer gave way.
(Actually bent the locking pin on my SOPMOD stock.)
There are a few things that you can do to tweak your setup to stretch every last bit of performance out of your rifle:
- First is the one that you probably didn't want to hear, adjustable gas system.
By either modifying your gas block to be one, or purchasing one, you can do a lot more fine tuning.
If you are like me though, you are likely a bit wary of introducing anything that has the potential to fail and induce problems.
Adjustable gas systems that use threaded valves can and do move over time in such a harsh environment.
- Second is going to be Buffer Weight.
You said that you are using the JP weights, but there is Slashes Heavy Buffers as well.
http://www.heavybuffers.com/
His buffers are designed specifically for what you are doing.
(This is where I would start if I were you.)
- Third is going to be further load development.
If you choose a powder and charge weight by its burn rate and pressure characteristics you could find a load that better meets your goals.
(Albeit, at the cost of time, money, and aggravation.)
Hope this helps...
Re: Low Mass or Lightweight Bolt Carriers
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dr. Phil</div><div class="ubbcode-body">Added mass = Increased Dwell Time
Increased Dwell Time = longer period of time for gas pressure to equalize
(Effectively providing similar results as less gas.)
That is why felt recoil is often attributed to Heavy Buffers / BCG.
Light Bolt Carrier = Minimal Dwell Time & Minimal Reciprocating Mass
Minimal Dwell Time = Higher RPM
Higher RPM = Hard on Brass due to brass still being under pressure
Minimal Reciprocating Mass = Less Mass Transferred via Inertia
As an added note:
Heavy Buffers, Full Auto Bolt Carrier Groups, and Enhanced Action Springs are excellent ways to increase reliability by increasing the amount of force driving the action.
They also make suppressed firing of an AR a much more pleasant experience.
This occurs because the increased dwell time allows more gas to escape from the gun prior to the action cycling.
Three Gun Shooting is a different animal than defensive of combat use of a carbine.
In USPSA, you only have a bad match if your gun goes down.
The same can not be said for the latter…
When it comes to USPSA / Three Gun stuff, Zak Smith is a big player and is one your should listen to closely.
(He is also an ok guy...) </div></div>
Great post. Thank you.
So why do both the heavier buffer/carrier people and the lighter buffer/carrier people claim less recoil? To me heavy buffer/carrier feels slower and more rolling and lighter = more snappy and sharp.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dr. Phil</div><div class="ubbcode-body">Added mass = Increased Dwell Time
Increased Dwell Time = longer period of time for gas pressure to equalize
(Effectively providing similar results as less gas.)
That is why felt recoil is often attributed to Heavy Buffers / BCG.
Light Bolt Carrier = Minimal Dwell Time & Minimal Reciprocating Mass
Minimal Dwell Time = Higher RPM
Higher RPM = Hard on Brass due to brass still being under pressure
Minimal Reciprocating Mass = Less Mass Transferred via Inertia
As an added note:
Heavy Buffers, Full Auto Bolt Carrier Groups, and Enhanced Action Springs are excellent ways to increase reliability by increasing the amount of force driving the action.
They also make suppressed firing of an AR a much more pleasant experience.
This occurs because the increased dwell time allows more gas to escape from the gun prior to the action cycling.
Three Gun Shooting is a different animal than defensive of combat use of a carbine.
In USPSA, you only have a bad match if your gun goes down.
The same can not be said for the latter…
When it comes to USPSA / Three Gun stuff, Zak Smith is a big player and is one your should listen to closely.
(He is also an ok guy...) </div></div>
Great post. Thank you.
So why do both the heavier buffer/carrier people and the lighter buffer/carrier people claim less recoil? To me heavy buffer/carrier feels slower and more rolling and lighter = more snappy and sharp.
Re: Low Mass or Lightweight Bolt Carriers
I will leave all the heavy math and physics to the other posters and will say my comments are based on shooting + build budget. I have the JP low mass BCG in my MA-TEN 308 and would likely not put it in another build IMHO not worth the extra cost vs. DPMS or the new Young MFG BCG. That said the Slash Heavy Buffer is a +++1 and I liked it so much just put one in my AR 15. Recoil in an AR 15 to me is minnimal in the worst case scenerios but for better follow up I would install a good break i.e. JP, Jerry M, PWS etc.
I will leave all the heavy math and physics to the other posters and will say my comments are based on shooting + build budget. I have the JP low mass BCG in my MA-TEN 308 and would likely not put it in another build IMHO not worth the extra cost vs. DPMS or the new Young MFG BCG. That said the Slash Heavy Buffer is a +++1 and I liked it so much just put one in my AR 15. Recoil in an AR 15 to me is minnimal in the worst case scenerios but for better follow up I would install a good break i.e. JP, Jerry M, PWS etc.
Re: Low Mass or Lightweight Bolt Carriers
heres all the weights of the diffrent carriers and buffers I have here right now.
stag carrier 258 grams
DPMS carrier 254 crams
JP full mass carrier 244 grams
JP low mass carrier 188 grams
standard rifle buffer 150 grams
JP low mass buffer 92 grams
carbine buffer 80 grams
heres all the weights of the diffrent carriers and buffers I have here right now.
stag carrier 258 grams
DPMS carrier 254 crams
JP full mass carrier 244 grams
JP low mass carrier 188 grams
standard rifle buffer 150 grams
JP low mass buffer 92 grams
carbine buffer 80 grams
Re: Low Mass or Lightweight Bolt Carriers
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dr. Phil</div><div class="ubbcode-body">Added mass = Increased Dwell Time
Increased Dwell Time = longer period of time for gas pressure to equalize
(Effectively providing similar results as less gas.)
That is why felt recoil is often attributed to Heavy Buffers / BCG.
Light Bolt Carrier = Minimal Dwell Time & Minimal Reciprocating Mass
Minimal Dwell Time = Higher RPM
Higher RPM = Hard on Brass due to brass still being under pressure
Minimal Reciprocating Mass = Less Mass Transferred via Inertia
As an added note:
Heavy Buffers, Full Auto Bolt Carrier Groups, and Enhanced Action Springs are excellent ways to increase reliability by increasing the amount of force driving the action.
They also make suppressed firing of an AR a much more pleasant experience.
This occurs because the increased dwell time allows more gas to escape from the gun prior to the action cycling.
Three Gun Shooting is a different animal than defensive of combat use of a carbine.
In USPSA, you only have a bad match if your gun goes down.
The same can not be said for the latter…
When it comes to USPSA / Three Gun stuff, Zak Smith is a big player and is one your should listen to closely.
(He is also an ok guy...)</div></div>
You are largely correct, but you are missing a large portion of the equation: adjustable gas blocks.
There are two distinct recoil pulses in an AR-style rifle. One is the round going off (like a bolt gun has) the second is usually the buffer hitting the rear of the buffer tube. A lightweight carrier and/or buffer will do little to reduce the recoil by themselves. While the mass has been reduced, the velocity has increased (which is why a more powerful spring is recommended).
If an adjustable gas block is used, the second recoil pulse can be eliminated completely. Instead of slamming to the rear of the buffer tube, the carrier and buffer simply go back far enough to strip a new round out of the magazine or lock back with the bolt catch. This eliminates the argument of decreased dwell time and torn up brass with a lightweight carrier and buffer.
With the second recoil pulse removed, the primary recoil pulse can be mitigated by a muzzle brake. With the laws of physics being what they are though, the movement of nearly 1lb of steel back and forth internally will cause the rifle to move, hence the desirability of the lightened components.
I have adjustable gas blocks on a 20" HBAR with a full-auto carrier and a standard rifle buffer and on my 3-gun rifle which is as light as possible (carbon fiber handguard and such) and has all the weight removed from the buffer. There is a noticeable difference between a standard buffer and a "weightless" when firing multiple shots at multiple targets quickly, but 3-gun is a game, not combat.
That said, I would not use an adjustable gas block on a "fighting" rifle. The gas block will essentially be set for one particular load and other ammo may not cycle the rifle at all.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dr. Phil</div><div class="ubbcode-body">Added mass = Increased Dwell Time
Increased Dwell Time = longer period of time for gas pressure to equalize
(Effectively providing similar results as less gas.)
That is why felt recoil is often attributed to Heavy Buffers / BCG.
Light Bolt Carrier = Minimal Dwell Time & Minimal Reciprocating Mass
Minimal Dwell Time = Higher RPM
Higher RPM = Hard on Brass due to brass still being under pressure
Minimal Reciprocating Mass = Less Mass Transferred via Inertia
As an added note:
Heavy Buffers, Full Auto Bolt Carrier Groups, and Enhanced Action Springs are excellent ways to increase reliability by increasing the amount of force driving the action.
They also make suppressed firing of an AR a much more pleasant experience.
This occurs because the increased dwell time allows more gas to escape from the gun prior to the action cycling.
Three Gun Shooting is a different animal than defensive of combat use of a carbine.
In USPSA, you only have a bad match if your gun goes down.
The same can not be said for the latter…
When it comes to USPSA / Three Gun stuff, Zak Smith is a big player and is one your should listen to closely.
(He is also an ok guy...)</div></div>
You are largely correct, but you are missing a large portion of the equation: adjustable gas blocks.
There are two distinct recoil pulses in an AR-style rifle. One is the round going off (like a bolt gun has) the second is usually the buffer hitting the rear of the buffer tube. A lightweight carrier and/or buffer will do little to reduce the recoil by themselves. While the mass has been reduced, the velocity has increased (which is why a more powerful spring is recommended).
If an adjustable gas block is used, the second recoil pulse can be eliminated completely. Instead of slamming to the rear of the buffer tube, the carrier and buffer simply go back far enough to strip a new round out of the magazine or lock back with the bolt catch. This eliminates the argument of decreased dwell time and torn up brass with a lightweight carrier and buffer.
With the second recoil pulse removed, the primary recoil pulse can be mitigated by a muzzle brake. With the laws of physics being what they are though, the movement of nearly 1lb of steel back and forth internally will cause the rifle to move, hence the desirability of the lightened components.
I have adjustable gas blocks on a 20" HBAR with a full-auto carrier and a standard rifle buffer and on my 3-gun rifle which is as light as possible (carbon fiber handguard and such) and has all the weight removed from the buffer. There is a noticeable difference between a standard buffer and a "weightless" when firing multiple shots at multiple targets quickly, but 3-gun is a game, not combat.
That said, I would not use an adjustable gas block on a "fighting" rifle. The gas block will essentially be set for one particular load and other ammo may not cycle the rifle at all.
Re: Low Mass or Lightweight Bolt Carriers
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 30378</div><div class="ubbcode-body"><span style="font-weight: bold">I guess I should have mentioned in the original question, this is a competition 6.8 SPC II. It will see mostly competition events, no actual self defense, and minimal hunting. Major objective is reducing total rifle weight to enhance speed of handling the weapon. I am also leaning toward the one from Young Manufacturing.</span>
http://www.youngmanufacturing.net/product-info.php?pid102.html</div></div>
<span style="font-family: 'Times New Roman'">Ya, kinda woulda helped since 6.8 is way different tha n5.56 in recoil, and because 3-gun is as-fast-as-possible shooting which got our buddies all tangle up.
One 6.8 expert is <span style="text-decoration: underline"><span style="font-style: italic">ARPerforma</span>nce</span>. They are right on.
If I may be so audacious to judge another's comments, so too is Dr. Phil. Delaying unlocking of the breach, thus relieving pressure, is good, except in timed, competition shooting events, apparently, according to those gentlemen.
30378; Save some money and be proud of your handy work by doing this:
<ul style="list-style-type: disc">[*]Hand lap your reciever and buffer tube.[*]Using 400, then 1000 grit emery, polish the four contact rails on the carrier as well as the tail of the carrier.
[*]Replace the crappy buffer spring with a Tubb CS spring. [*]Lubricate the exterior surfaces of the carrier, buffer, and buffer spring with synthetic engine oil. Lube the lugs with a thin amount of grease. [*]Polish the chamber, bolt face, and extractor.
[/list] [*]
We assume you run the best single-stage trigger.
A piss ant weighs 3-4 ounces so that's a wash.
Lube and polish will make it shoot faster so that's done.
What else?
Sounds smart alecky, but my point is much of these products is just a way for a stiff shirt company man to build a new house. Don't fall for it. Save it and build yourself one.
</span>
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 30378</div><div class="ubbcode-body"><span style="font-weight: bold">I guess I should have mentioned in the original question, this is a competition 6.8 SPC II. It will see mostly competition events, no actual self defense, and minimal hunting. Major objective is reducing total rifle weight to enhance speed of handling the weapon. I am also leaning toward the one from Young Manufacturing.</span>
http://www.youngmanufacturing.net/product-info.php?pid102.html</div></div>
<span style="font-family: 'Times New Roman'">Ya, kinda woulda helped since 6.8 is way different tha n5.56 in recoil, and because 3-gun is as-fast-as-possible shooting which got our buddies all tangle up.
One 6.8 expert is <span style="text-decoration: underline"><span style="font-style: italic">ARPerforma</span>nce</span>. They are right on.
If I may be so audacious to judge another's comments, so too is Dr. Phil. Delaying unlocking of the breach, thus relieving pressure, is good, except in timed, competition shooting events, apparently, according to those gentlemen.
30378; Save some money and be proud of your handy work by doing this:
<ul style="list-style-type: disc">[*]Hand lap your reciever and buffer tube.[*]Using 400, then 1000 grit emery, polish the four contact rails on the carrier as well as the tail of the carrier.
[*]Replace the crappy buffer spring with a Tubb CS spring. [*]Lubricate the exterior surfaces of the carrier, buffer, and buffer spring with synthetic engine oil. Lube the lugs with a thin amount of grease. [*]Polish the chamber, bolt face, and extractor.
[/list] [*]
We assume you run the best single-stage trigger.
A piss ant weighs 3-4 ounces so that's a wash.
Lube and polish will make it shoot faster so that's done.
What else?
Sounds smart alecky, but my point is much of these products is just a way for a stiff shirt company man to build a new house. Don't fall for it. Save it and build yourself one.
</span>
Re: Low Mass or Lightweight Bolt Carriers
Awesome. This is it:
If an adjustable gas block is used, the second recoil pulse can be eliminated completely. Instead of slamming to the rear of the buffer tube, the carrier and buffer simply go back far enough to strip a new round out of the magazine or lock back with the bolt catch.
Thanks to MAUS3R.
Awesome. This is it:
If an adjustable gas block is used, the second recoil pulse can be eliminated completely. Instead of slamming to the rear of the buffer tube, the carrier and buffer simply go back far enough to strip a new round out of the magazine or lock back with the bolt catch.
Thanks to MAUS3R.
Re: Low Mass or Lightweight Bolt Carriers
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Casey Simpson</div><div class="ubbcode-body">Awesome. This is it:
If an adjustable gas block is used, the second recoil pulse can be eliminated completely. Instead of slamming to the rear of the buffer tube, the carrier and buffer simply go back far enough to strip a new round out of the magazine or lock back with the bolt catch.
Thanks to MAUS3R.</div></div>
keep in mind that if you tune it that much, you can't "just run it wet". you actually will have to clean it religiously or a little sludge in there will change the resistance enough to stop the bolt from holding open.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Casey Simpson</div><div class="ubbcode-body">Awesome. This is it:
If an adjustable gas block is used, the second recoil pulse can be eliminated completely. Instead of slamming to the rear of the buffer tube, the carrier and buffer simply go back far enough to strip a new round out of the magazine or lock back with the bolt catch.
Thanks to MAUS3R.</div></div>
keep in mind that if you tune it that much, you can't "just run it wet". you actually will have to clean it religiously or a little sludge in there will change the resistance enough to stop the bolt from holding open.
Re: Low Mass or Lightweight Bolt Carriers
Good, taliv. Maybe they will lubricate and clean their weapons.
Good, taliv. Maybe they will lubricate and clean their weapons.
Re: Low Mass or Lightweight Bolt Carriers
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ASM1</div><div class="ubbcode-body">What spring and buffer,are you useing ? AR15 m4 TUBE or 10 length tube?
I am throwing 150's from a 18" Noveske barrel 2900fps,I had no trouble without the Can,But I added the Can and it would overrun the spent case and shut on it before it could leave the rec. I added the Tubs carrier weight and it stopped doing that. I am useing the AR15 M4 tube and heavy buffer from the guy on ARFCOM..</div></div>
On the 308, I'm running a 308 rifle length buffer and the Tubb flat wire spring (which is freakin' sweet btw). Benny lightened up the buffer too. Since you're running a suppressed rifle, I think you'd be looking at the Noveske Switchblock.
Rich
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ASM1</div><div class="ubbcode-body">What spring and buffer,are you useing ? AR15 m4 TUBE or 10 length tube?
I am throwing 150's from a 18" Noveske barrel 2900fps,I had no trouble without the Can,But I added the Can and it would overrun the spent case and shut on it before it could leave the rec. I added the Tubs carrier weight and it stopped doing that. I am useing the AR15 M4 tube and heavy buffer from the guy on ARFCOM..</div></div>
On the 308, I'm running a 308 rifle length buffer and the Tubb flat wire spring (which is freakin' sweet btw). Benny lightened up the buffer too. Since you're running a suppressed rifle, I think you'd be looking at the Noveske Switchblock.
Rich
Re: Low Mass or Lightweight Bolt Carriers
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308MAUS3R</div><div class="ubbcode-body">You are largely correct, but you are missing a large portion of the equation: adjustable gas blocks.</div></div>I mentioned adjustable gas systems in my second post.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dr. Phil</div><div class="ubbcode-body">There are a few things that you can do to tweak your setup to stretch every last bit of performance out of your rifle:
- First is the one that you probably didn't want to hear, adjustable gas system.
By either modifying your gas block to be one, or purchasing one, you can do a lot more fine tuning.
If you are like me though, you are likely a bit wary of introducing anything that has the potential to fail and induce problems.
Adjustable gas systems that use threaded valves can and do move over time in such a harsh environment.</div></div>Initially I was just trying to address the light vs. heavy BCG question.
Your input and description of a "Perfect Tuning" is excelent.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: uscbigdawg</div><div class="ubbcode-body">On the 308, I'm running a 308 rifle length buffer and the Tubb flat wire spring (which is freakin' sweet btw). Benny lightened up the buffer too. Since you're running a suppressed rifle, I think you'd be looking at the Noveske Switchblock.
Rich
</div></div>The Switch Block is a great solution, but it does not allow for the fine tuning for competition that is being discussed here.
For a "Fighting Rifle", the Switch Block is much more appropriate since it is less prone to error / failure than a regular adjustable block.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308MAUS3R</div><div class="ubbcode-body">You are largely correct, but you are missing a large portion of the equation: adjustable gas blocks.</div></div>I mentioned adjustable gas systems in my second post.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dr. Phil</div><div class="ubbcode-body">There are a few things that you can do to tweak your setup to stretch every last bit of performance out of your rifle:
- First is the one that you probably didn't want to hear, adjustable gas system.
By either modifying your gas block to be one, or purchasing one, you can do a lot more fine tuning.
If you are like me though, you are likely a bit wary of introducing anything that has the potential to fail and induce problems.
Adjustable gas systems that use threaded valves can and do move over time in such a harsh environment.</div></div>Initially I was just trying to address the light vs. heavy BCG question.
Your input and description of a "Perfect Tuning" is excelent.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: uscbigdawg</div><div class="ubbcode-body">On the 308, I'm running a 308 rifle length buffer and the Tubb flat wire spring (which is freakin' sweet btw). Benny lightened up the buffer too. Since you're running a suppressed rifle, I think you'd be looking at the Noveske Switchblock.
Rich
</div></div>The Switch Block is a great solution, but it does not allow for the fine tuning for competition that is being discussed here.
For a "Fighting Rifle", the Switch Block is much more appropriate since it is less prone to error / failure than a regular adjustable block.
Re: Low Mass or Lightweight Bolt Carriers
If I were setting up a rifle for a low mass carrier/buffer system, I'd either have an adjustable gas block, or I'd drill the gas port small and work my way up until functining was reliable.
If I were setting up a rifle for a low mass carrier/buffer system, I'd either have an adjustable gas block, or I'd drill the gas port small and work my way up until functining was reliable.
Re: Low Mass or Lightweight Bolt Carriers
Sorry for going MIA on this thread. I must have lost notifications or something. Anyway, reliability, while not life threatening, is KEY to 3Gun competition. It doesn't matter how fast your rifle runs or how good you are if your rifle malfunctions. That is why I ended up with the configuration of 3Gun upper that I did-- it was designed to withstand an "ITRC super high round count" event without any reliability or accuracy issues (after I had witnessed a bunch of problems on other rifles and shot my JP CTR-02 with original LMOS in the 2004 ITRC).
Also, with regard to setting up the system to "just move back enough to strip the next round", I strong recommend against that. The longer the mass is in motion the longer the rifle will be moving. Tavlis' point about reliability in that regime is also spot on.
regards
Zak
Sorry for going MIA on this thread. I must have lost notifications or something. Anyway, reliability, while not life threatening, is KEY to 3Gun competition. It doesn't matter how fast your rifle runs or how good you are if your rifle malfunctions. That is why I ended up with the configuration of 3Gun upper that I did-- it was designed to withstand an "ITRC super high round count" event without any reliability or accuracy issues (after I had witnessed a bunch of problems on other rifles and shot my JP CTR-02 with original LMOS in the 2004 ITRC).
Also, with regard to setting up the system to "just move back enough to strip the next round", I strong recommend against that. The longer the mass is in motion the longer the rifle will be moving. Tavlis' point about reliability in that regime is also spot on.
regards
Zak
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