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Colt M4 Commando - Keep the factory 11.5 or DD MK18 upper?

sw99

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Full Member
Minuteman
May 17, 2004
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Weld CO
The factory 11.5 upper works great, no complaints. I have been toying with the idea of getting the DD MK18 upper.Seems like the MK18 gets rave reviews and I can get one at a great price. I would be selling my factory 11.5 to fund the MK18. Is there really any big advantage of swapping to the MK18? Looking for reliability, accuracy and longevity.
 
No reason to switch over unless you love the RIS rail. You will lose some performance going from a 11.5 to 10.5 and the 11.5 should theoreticaly be more reliable/smoother than the 10.5

If it were me, I would shave/dremel/smooth the FSB into a low profile gasblock and put the FF rail of your choice on there. Will save a bunch of money, and can keep that quality colt barrel and gas system. Don't buy into all the CHF or other marketing bullshit. Your going to spend $10K in ammo before you shoot that colt barrel out or erode the gas port to the point of reliability issues. Rock and roll with what you have.

EDIT to add: Do you plan to supress this or run this as a suppresed gun primarily?
 
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No reason to switch over unless you love the RIS rail. You will lose some performance going from a 11.5 to 10.5 and the 11.5 should theoreticaly be more reliable/smoother than the 10.5

Losing one inch of barrel on an already short setup will do very little for you in the reliability department. If anything you might lose 15-20 fps on factory ammo.
Smoother? No such thing….. in an SBR. Smoothest AR15 I have ever ran was the WAR SPORT LVOA in a 14.5" setup. That thing was so flat shooting that it was shocking, very impressive technology.
Keep in mind these SBR's are for CQB and not really optimized for the longer shots, they fill a specific role. As long as you are 150 yards and in, you will not see a difference in 1" of barrel.

I have run a 10.5" SBR for 9 years now with no failures and have made solid hits out to 400 yards with an Aimpoint T1 and 3x magnifier. I run it both suppressed and not suppressed with zero issues.
It is a Noveske upper with their Switchblock. If you do want to run it both suppressed and not I highly suggest looking at a gas block that you can switch modes on. Once you drop below a 14.5" barrel its all small details. 7.5", 8.5", 9, 10.5". and 12" barrels are pretty much role specific or novelty items.
 
Losing one inch of barrel on an already short setup will do very little for you in the reliability department. If anything you might lose 15-20 fps on factory ammo.
Smoother? No such thing….. in an SBR. Smoothest AR15 I have ever ran was the WAR SPORT LVOA in a 14.5" setup. That thing was so flat shooting that it was shocking, very impressive technology.
Keep in mind these SBR's are for CQB and not really optimized for the longer shots, they fill a specific role. As long as you are 150 yards and in, you will not see a difference in 1" of barrel.

I have run a 10.5" SBR for 9 years now with no failures and have made solid hits out to 400 yards with an Aimpoint T1 and 3x magnifier. I run it both suppressed and not suppressed with zero issues.
It is a Noveske upper with their Switchblock. If you do want to run it both suppressed and not I highly suggest looking at a gas block that you can switch modes on. Once you drop below a 14.5" barrel its all small details. 7.5", 8.5", 9, 10.5". and 12" barrels are pretty much role specific or novelty items.
Will you just stop with your bullshit? Your wrong once again so give it up. You lose about 100fps going from 11.5 to 10.5 and a reduced dwell time. It is without a doubt smoother as there is more weight and is the best compromise between velocity and barrel length with a shorty. Do you need me to post ballistic tables or draw a picture for you to understand? If you want t follow me around from thread to thread at least have your info right.
 
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I am not really concerned with the slight loss in accuracy and FPS. I have a couple AR10's for reaching out if needed. I like the longer free float rails but it's not a requirement. It would be nice to have a flip up front sight but on the same token, I am used to running a fixed with my EoTech.

Any idea what an M4 Commando upper is going for these days? If I can offset the cost quite a bit it may be worth it to me.
 
The 11.5 will allow you to run a longer rail of you want the space. Your upper with bcg would sell for a nice penny to the right buyer. Keep in mind you would still be about $4-500 away after selling it to buy a new mk18 upper. That money could be used to get a better rail than the ris and a nice set of buis to go with your eotech. If it was my money, I would put a 10" BCM KMR rail on your colt and a set of magpul pro buis. I would keep the colt but if you need the clone them jus do it. Just understand the performance and handling differences between them.
 
I like the MK18 myself so i kinda did a build around it that i stuck on a new pistol lower to wait for the SBR paper work to come back. I got a DD 9.5 lite MK18 rail and went with the Bravo Company Hammer forged chrome lined 11.5 barrel. a Seekins upper and Raptor charging handle. I will be using a Micro T1 on it and a Surefire Socom RC suppressor. Do you guys think i need to switch out the low profile gas block for a switch style gas block ? I also went with the Bravo company BCG it's being micro slicked at Custom Gun Coating company now.
 
For a 10.5 in gun you need to understand that it's gong to be over gassed. This is to ensure reliability with the short gas system and fast dwell time. The reason the hk416 was deveolped was to A have a reliable short barrel AR (at the time shorties were not reliable like they are now) and B to cut down on gas in the shooters face from a massively over gassed system once the can is on. Adjustable gas blocks are always a good thing but they may limit rails and cans depending on your setup. Better to overgas than undergas. Make sure there is enough clearance for your sure firebreak and can.
 
10.5" guns are something that probably should have gone away after the experiences with the Model 607, and XM177E1.

I've had nothing but very reliable performance from 11.5" guns over the years, dating back from the 1990's to the present, to include high volume sessions in extreme cold. I've also seen a lot of 10.5" guns have issues with early unlocking, case head separation, hard on extractors, hard on gas rings, and they just aren't the optimum barrel length and gas system length combo. SF and NAVSPECWAR have re-visited the same lessons-learned from the mid-1960's, which should never have had to happen.

11.5" guns get way better velocity than most people think as well. I have zero problem with them in the green, and they hit hard at 300m with 5.56 NATO. Run 70gr TSX through them and prepare to commence to slaying.

I personally would not opt for a 10.5" gun over an 11.5". It's going backwards in the knowledge base we have on the Commado variants. Since you live in CO, you will be dealing with much lower average temps than someone in the South, so dwell time + ambient temperature become issues you really need to pay attention to more.
 
Will you just stop with your bullshit? Your wrong once again so give it up. You lose about 100fps going from 11.5 to 10.5 and a reduced dwell time. It is without a doubt smoother as there is more weight and is the best compromise between velocity and barrel length with a shorty. Do you need me to post ballistic tables or draw a picture for you to understand? If you want t follow me around from thread to thread at least have your info right.

You don't need to get so bent out of shape. But the fact remains, you are WRONG. 100 fps in 1" of barrel!? PLEASE show me some proof as I have already done this quite a few times. I have data from 16" down to a 7.5" barrel. Why? Because I own all of them in between and have ran thousands of rounds thru all of them.
You need to stop pretending like you are the know it all center of information and accept the fact that sometimes you are going to be proven wrong. Call any ammo manufacturer or AR15 manufacturer and ask them about your supposed theory. They will tell you it's wrong. One inch of barrel will not make any difference except for bullet velocity. You can change your "dwell time" by changing out the buffer and spring for heavier weights. That counteracts any issue with over gassing due to the shorter burn rate of a SBR setup.
 
You don't need to get so bent out of shape. But the fact remains, you are WRONG. 100 fps in 1" of barrel!? PLEASE show me some proof as I have already done this quite a few times. I have data from 16" down to a 7.5" barrel. Why? Because I own all of them in between and have ran thousands of rounds thru all of them.
You need to stop pretending like you are the know it all center of information and accept the fact that sometimes you are going to be proven wrong. Call any ammo manufacturer or AR15 manufacturer and ask them about your supposed theory. They will tell you it's wrong. One inch of barrel will not make any difference except for bullet velocity. You can change your "dwell time" by changing out the buffer and spring for heavier weights. That counteracts any issue with over gassing due to the shorter burn rate of a SBR setup.



Some interesting data for the 10.5" vs 11.5" barrel selection process. - AR15.Com Archive
10.5 vs 11.5
BBTI - Ballistics by the Inch :: .223 Rifle Results

"We didn't do a full run with the Black Hills in all the guns. But it averaged ~2550 FPS in one 5 shot string in the 11.5" and ~2350 in the 10.3". In my 18" SPR it averaged ~ 2750 (and shoots well under a 1/2 MOA at 100 yards; that's the gun I usually shoot it in)"

"For a long time the 11.5 was considered a more reliable barrel length, plus it had the additional velocity for fragmentation. The main reason the 10.5 stuck around was because of the military using it. Now, things have changed a bit, and the 10.5s are pretty squared away. Paul from BCM has mentioned in the past that the 11.5, with its extra inch of barrel past the gas-port, retains a 40% longer dwell time than the 10.5". I think you start to really see this become important as weapons get dirty, temperatures change, weaker ammo is used, or other things come into play."

"Yes, the 10.5" is more violent, so it ends up being higher wear and tear. The 10.5" barrels are brutal on cans"


Your not the only one who has run various barrel lengths. I have for years and thousands of other users have as well. There is a reason both KAC and BCM sell 11.5 inch SBR uppers/guns and not 10.5. The reliability and 40% greater dwell time is more than enough justification. The additional velocity extending the fragmentation range is just icing on the cake.

I suggest you read more and post less. YOU ARE WRONG. The fact you want to be a smart ass about it and try and call me out makes you look like a moron. I don't know it all, but I sure as hell know more than you do, as evidenced by this post alone. 5.56/223 ballistics is not linear, you may want to invest in a chrono.


And in case your inclined, here is some light reading:
223 ballistics & effectiveness - pt1 of 2 - 223 / 5.56 / 9mm reload central database
Wound Ballistics: Basics and Applications - Beat Kneubuehl - Google Books
 
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You don't need to get so bent out of shape. But the fact remains, you are WRONG. 100 fps in 1" of barrel!? PLEASE show me some proof as I have already done this quite a few times. I have data from 16" down to a 7.5" barrel. Why? Because I own all of them in between and have ran thousands of rounds thru all of them.
You need to stop pretending like you are the know it all center of information and accept the fact that sometimes you are going to be proven wrong. Call any ammo manufacturer or AR15 manufacturer and ask them about your supposed theory. They will tell you it's wrong. One inch of barrel will not make any difference except for bullet velocity. You can change your "dwell time" by changing out the buffer and spring for heavier weights. That counteracts any issue with over gassing due to the shorter burn rate of a SBR setup.


In the real world its closer to 50~60 FPS for 1" of barrel @ that length.

The Effects Of Reducing The Barrel Length On Velocity And Accuracy In The 223 Remington



When I had a transferable M16-A1 I also had a shorty upper ( 10" ) and a standard carbine upper. The 10" ran fine with a standard bird cage or the XM177E2 "moderator" and I could not feel any "smoothness" difference from the 16" carbine and the 10". The shorter barrel had a brutal muzzle blast and it went by-by for A2 trim and configuration.

Adding an inch of barrel on the 10" making it 11" is similar to adding a foot on an ore boat and saying "it handles a lot better".
Maybe in your head or on paper.
 
In the real world its closer to 50~60 FPS for 1" of barrel @ that length.

The Effects Of Reducing The Barrel Length On Velocity And Accuracy In The 223 Remington



When I had a transferable M16-A1 I also had a shorty upper ( 10" ) and a standard carbine upper. The 10" ran fine with a standard bird cage or the XM177E2 "moderator" and I could not feel any "smoothness" difference from the 16" carbine and the 10". The shorter barrel had a brutal muzzle blast and it went by-by for A2 trim and configuration.

Adding an inch of barrel on the 10" making it 11" is similar to adding a foot on an ore boat and saying "it handles a lot better".
Maybe in your head or on paper.

Not for nothing, but you cherry picked a chart using 52 gr bullets (not close to issue) and who knows what powder, molly coated bullets and FGMM Primers.... while being from 2001. I already posted the chrono readings for various factory loads you would expect to shoot. That is the main reason most people who can run the 75/77 gr pills in them because you can't rely on fragmentation and hope for expansion and energy transfer into the target.
 
Interesting discussion. I have had an XM177E2 HB (an early 90's Bushmaster, when they were a fairly new company and before the black gun craze) for quite some time now. It has (IIRC) a 10.5" barrel with the stupid long 5.5" flash hider. Not too sure on the velocities debate here, but never really ran into any reliability issues, save when I was running some reloads using 4198 with 55gr FMJ's; no bueno (fine in a 20" rifle length gas system, but short stroked in the shorty).

Never noticed excessive wear on the brass though, maybe I got lucky? No pigtail, nothing other than milspec (to the MK1 eyeball) parts...

I will say, yes, it is a loud somvabitch...
 
Not for nothing, but you cherry picked a chart using 52 gr bullets (not close to issue) and who knows what powder, molly coated bullets and FGMM Primers.... while being from 2001. I already posted the chrono readings for various factory loads you would expect to shoot. That is the main reason most people who can run the 75/77 gr pills in them because you can't rely on fragmentation and hope for expansion and energy transfer into the target.

You are calling out someone for the gr weight bullet they chose to look at testing when you don't even supply information (speeds, deviation, failure rate) for the 77gr load that is carried in those Navy HK416's. I will get some data on that this coming Monday actually.

I have a chrono, a nice one as a matter of fact. I also carry a Magnetto in the truck if you want to borrow it..... they rarely lie to me.

Here is a Noveske 10.5" SBR that has seen well over 12k rounds. No failures. It's cleaned every 1k rounds.

2mq7myp.jpg


Here is a picture of the Noveske Switchblock. I high recommend it when going from suppressed to unsuppressed shooting:

5eftsh.jpg


The rails are 9.75" long. Compared to the 12" rails that are the most popular choice for 16" and 14.5" guns.... that is plenty of rail space for essential items.
 
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You are calling out someone for the gr weight bullet they chose to look at testing when you don't even supply information (speeds, deviation, failure rate) for the 77gr load that is carried in those Navy HK416's. I will get some data on that this coming Monday actually.

I have a chrono, a nice one as a matter of fact. I also carry a Magnetto in the truck if you want to borrow it..... they rarely lie to me.

SNIP

COOL STORY BRO. Looks like the asperger's brigade is in full force tonight. What in the blue fuck are you even talking about now. Speed = MV. Deviation is not a factor of barrel length, but quality of ammo and failure has zero to do with what we are talking about.

All the MV's for common ammo is listed. Oh cool you have a noveske, no one else has one of those or has ever ran a switchblock. Do you rub it on your balls at night and fondle your precious. Noveskes typically use a poly barrel that will have a higher avg MZ than a typical cut/button/chf grooved barrel.

Are you going bring forth any new information or arguments, or just bore us with your mundane shit all night? Just another dipshit who thinks his 1 gun is representative of every gun ever made. Don't even use big words like deviation, as you lack the mental capacity to comprehend it.

Rain man, is that you?
 
COOL STORY BRO. Looks like the asperger's brigade is in full force tonight. What in the blue fuck are you even talking about now. Speed = MV. Deviation is not a factor of barrel length, but quality of ammo and failure has zero to do with what we are talking about.

All the MV's for common ammo is listed. Oh cool you have a noveske, no one else has one of those or has ever ran a switchblock. Do you rub it on your balls at night and fondle your precious. Noveskes typically use a poly barrel that will have a higher avg MZ than a typical cut/button/chf grooved barrel.

Are you going bring forth any new information or arguments, or just bore us with your mundane shit all night? Just another dipshit who thinks his 1 gun is representative of every gun ever made. Don't even use big words like deviation, as you lack the mental capacity to comprehend it.

Rain man, is that you?

Can't you comprehend or do you always just outright attack the people you don't agree with? It's extremely juvenile and makes you look weak minded.

We are talking barrel lengths. No one here said anything about barrel specs. If I were you I would go back and read exactly what was stated and that was barrel length. Not twist style, barrel material, how sharp the rifling machine was, the guy didn't pull the machine out at the right time or whatever non pertaining fact you might throw out there next.

Let me break this down for you one more time, to bad we don't have crayon font on here, you would really excel at that point:

1) Speed = 2600 fps, 2700 fps, 2800 fps, 3000 fps. Do you see how that is working?

2) Deviation in the loads = what was the spread in the ammunition shot? 3 fps, 5 fps, 6, fps, 10 fps, 20 fps...... the ammo in the testing is every bit as scrutinized as the weapon. It is in fact the part that puts the holes in the target.

3) Failure rate during that ammunitions use = blown primers? To hot (over gas)? Does it fit the chamber spec? etc. etc.

This is really not that complicated, yet you want to play this game like you are Captain Obvious of the USS Turd Bowl. Let's go back to what you claim: that one inch of barrel makes an overall system "better" then its shorter counter part..... that is absurdity at its best. Copy and paste all the articles you can google because plenty more people have been out there disproving this myth. If shorter is less reliable, harsher recoil, and prone to failures why did the Navy have Crane develop an upper that was 10.5" long? And why did they stick with an HK416 in a 10.3" barrel instead of 11.5"?


Toecutter, is that you??

tumblr_ly1uckZm7y1r8byiqo2_1280.jpg
 
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Can't you comprehend or do you always just outright attack the people you don't agree with? It's extremely juvenile and makes you look weak minded.

We are talking barrel lengths. No one here said anything about barrel specs. If I were you I would go back and read exactly what was stated and that was barrel length. Not twist style, barrel material, how sharp the rifling machine was, the guy didn't pull the machine out at the right time or whatever non pertaining fact you might throw out there next.

Let me break this down for you one more time, to bad we don't have crayon font on here, you would really excel at that point:

1) Speed = 2600 fps, 2700 fps, 2800 fps, 3000 fps. Do you see how that is working?

2) Deviation in the loads = what was the spread in the ammunition shot? 3 fps, 5 fps, 6, fps, 10 fps, 20 fps...... the ammo in the testing is every bit as scrutinized as the weapon. It is in fact the part that puts the holes in the target.

3) Failure rate during that ammunitions use = blown primers? To hot (over gas)? Does it fit the chamber spec? etc. etc.

This is really not that complicated, yet you want to play this game like you are Captain Obvious of the USS Turd Bowl. Let's go back to what you claim: that one inch of barrel makes an overall system "better" then its shorter counter part..... that is absurdity at its best. Copy and paste all the articles you can google because plenty more people have been out there disproving this myth. If shorter is less reliable, harsher recoil, and prone to failures why did the Navy have Crane develop an upper that was 10.5" long? And why did they stick with an HK416 in a 10.3" barrel instead of 11.5"?

Lets cut to the chase, the only reason you even commented in here is to try and sling shit at me. You have been doing it in every thread I post in, so grow the fuck up.

I don't need a ballistics lesson from you, so save the condescending bullshit for someone who cares. You are grasping at straws and despite the fact that I can continue to pick apart every word you type, its getting tiring. At this point, its really not worth my time anymore dealing with your bullshit. Your whole post is so full of irrelevant and off base bullshit, it does not even dignify a proper response. Most of these stupid ass questions you are asking have already been answered, but you are too fucking dense to absorb what has already been posted. Why retype it? It would be wasted on you anyway, Rain man.
 
Lets cut to the chase, the only reason you even commented in here is to try and sling shit at me. You have been doing it in every thread I post in, so grow the fuck up.

I don't need a ballistics lesson from you, so save the condescending bullshit for someone who cares. You are grasping at straws and despite the fact that I can continue to pick apart every word you type, its getting tiring. At this point, its really not worth my time anymore dealing with your bullshit. Your whole post is so full of irrelevant and off base bullshit, it does not even dignify a proper response. Most of these stupid ass questions you are asking have already been answered, but you are too fucking dense to absorb what has already been posted. Why retype it? It would be wasted on you anyway, Rain man.

Don't flatter yourself, no one follows you anywhere on this forum. I'm sure they run the opposite direction because they are worried if they do not agree with you that you will haul off and insult them. Since that seems to be your SOP.

I came into this thread to answer a question by another member. What got me into AR15's and other various semi auto rifles was the NFA allure of SBR's, machine guns, AOWs, SBS and other setups. I have been using them for a while now and have compiled enough knowledge to know my statements here are factual.
I also have several close friends that are in the special forces community and I also count on their experiences and knowledge to back up what I have seen first hand.

You do whatever makes you sleep better at night. I for one know that I do not need to come on here and barrage people with name calling and other dimwitted insults. You keep on thinking you are right on everything! :rolleyes:
 
Sounds like I will personally gain nothing from going to the MK18. I think I'm leaning towards keeping this and just shooting it. It looks like I already have a solid platform. I appreciate the feedback, thoughts and info on velocities and such....
 
Sounds like I will personally gain nothing from going to the MK18. I think I'm leaning towards keeping this and just shooting it. It looks like I already have a solid platform. I appreciate the feedback, thoughts and info on velocities and such....

For what you have, you made the right choice. There will be no major change in reliability or performance given they are so close in BBL length. I would enjoy what you have and as it wears out considering upgrading your barrel and rails at that point. Save some money by doing the work yourself, its easy with the appropriate tools.
 
just get the 7.5" awesome sauce(still makes holes not ninji star keyslots at 100 yards last i checked) cuz the chicks dig it and it fits in a gymbag better, and get over your juvenile arguments fellas, geez.
 
just get the 7.5" awesome sauce(still makes holes not ninji star keyslots at 100 yards last i checked) cuz the chicks dig it and it fits in a gymbag better, and get over your juvenile arguments fellas, geez.

yea ok... working on your post count?
 
<a href="http://photobucket.com/images/retard" target="_blank"><img src="http://i708.photobucket.com/albums/ww88/IBALLTAZER/retarted.jpg" border="0" alt="retard photo: RETARD retarted.jpg"/></a>
 
Its a shame no one here knows DICK about rifles or basic ballistics
This is just stupid
Go get the new BCM 5.5" upper with the micro length gas tube, since you already have a long SBR upper.
You paid for short so get the shortest one possible.
 
Don't flatter yourself, no one follows you anywhere on this forum. I'm sure they run the opposite direction because they are worried if they do not agree with you that you will haul off and insult them. Since that seems to be your SOP.

I came into this thread to answer a question by another member. What got me into AR15's and other various semi auto rifles was the NFA allure of SBR's, machine guns, AOWs, SBS and other setups. I have been using them for a while now and have compiled enough knowledge to know my statements here are factual.
I also have several close friends that are in the special forces community and I also count on their experiences and knowledge to back up what I have seen first hand.

You do whatever makes you sleep better at night. I for one know that I do not need to come on here and barrage people with name calling and other dimwitted insults. You keep on thinking you are right on everything! :rolleyes:
This is directed to Cal50, the poor aspergers paitent as well:

Yet you follow me into every thread? Interesting. Truth is, you don't know shit. Your small sample and experince and not indicative of reality. People MUCH more experienced and smarter than the both of us have already figured this out and lay out the tangible difference. So you are either an idiot, or you are just arguing for the sake of arguing. You are giving shitty advice that is fundamentally WRONG while trying to be a jackass to people who are trying to help. So give it a rest. I already showed you multiple examples of why you are WRONG. You ask for a table, and I post it, then you discount it like anything else that doesn’t fit you narrative.

I sleep fantastic at night. As long as morons like you give out factually incorrect information and poor advice, I will call you out. If you want to be a dick about it and get into a pissing match, then the only person to blame is yourself. If you are too sensitive to be corrected when you are wrong, then look into another hobby like knitting or quilt making. I hear they don't like confrontation.

For what you have, you made the right choice. There will be no major change in reliability or performance given they are so close in BBL length. I would enjoy what you have and as it wears out considering upgrading your barrel and rails at that point. Save some money by doing the work yourself, its easy with the appropriate tools.


Oh so now it’s no MAJOR changes? I thought it was 60 FPS or less? So you two continue to post false and incorrect information that is PROVEN to be wrong, and then blow it off and won't admit you are wrong. The fact that there is a substantial change in reliability AND performance is the whole point of these posts. Next you’re going to tell me gas port erosion is the same with a 10.5 and 11.5 in barrel. Give it a break.
 
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This is directed to Cal50, the poor aspergers paitent as well:

Yet you follow me into every thread? Interesting. Truth is, you don't know shit. Your small sample and experince and not indicative of reality. People MUCH more experienced and smarter than the both of us have already figured this out and lay out the tangible difference. So you are either an idiot, or you are just arguing for the sake of arguing. You are giving shitty advice that is fundamentally WRONG while trying to be a jackass to people who are trying to help. So give it a rest. I already showed you multiple examples of why you are WRONG. You ask for a table, and I post it, then you discount it like anything else that doesn’t fit you narrative.

I sleep fantastic at night. As long as morons like you give out factually incorrect information and poor advice, I will call you out. If you want to be a dick about it and get into a pissing match, then the only person to blame is yourself. If you are too sensitive to be corrected when you are wrong, then look into another hobby like knitting or quilt making. I hear they don't like confrontation.




Oh so now it’s no MAJOR changes? I thought it was 60 FPS or less? So you two continue to post false and incorrect information that is PROVEN to be wrong, and then blow it off and won't admit you are wrong. The fact that there is a substantial change in reliability AND performance is the whole point of these posts. Next you’re going to tell me gas port erosion is the same with a 10.5 and 11.5 in barrel. Give it a break.


You are so close minded and basic that I am shocked you can breathe on your own. How old are those "charts"? They don't show the few key types of ammo that are in use now with these short uppers! The only one I see that is widely used is LC Green Tip.

I am saying it and will continue to say it thru experience with the weapon systems. ONE INCH OF BARREL does not matter in performance, dwell time, gas port erosion, crown erosions, throat erosion, or whatever bullshit erosion you can think of next!

What I also find ironic is the fact that you can copy and paste like a champ but not one time have you said anything about proving these theories on your own. 40-50 fps is all you will lose in one inch of barrel on an SBR once you drop below a 14.5" barrel. Add a suppressor and that changes again. A tuned gas system, changes again. See the pattern here? Then you consider the different types of barrel materials and rifling styles. A lot of factors but when it comes down to commonalities of barrel length to performance ratio…. your claims of 100 fps per inch, smoother cycling, lower dwell times, and all sorts of other rampant bullshit are quite funny. So you are the one spreading false information! Ive spent a lot of time behind a rifle and chrono trying different types of ammo so I could record what I found and have a nice data table for the types of ammo I keep on hand. I know my results are factual and proven, yours are supposedly correct because they came from the internet? Oh ok……. man you are a smart guy, congrats on your achievement. Did you get a blister from the keyboard and mouse?

I will also tell you how your chart is flawed….

Let's look at the XM193 test numbers:

1) They have their control barrel (20") putting down an average of 3165 +/- 40 fps. So that is a pretty decent ammo for this testing being that its light, fast, and for AR15 ammo the speed deviation is not terrible. A 5 shot string never even gets the barrel warm.
2) Now you drop down to a 14.5" Barrel length and it's doing 3002, so if that 40 fps deviation happened you are talking a difference of 123 fps over 5.5" of barrel. A far cry from your alleged 100 fps per inch of barrel. That equates to 22.3 fps per inch of barrel, add the 40 fps thats 62 fps per inch.
3) The 11.5" barrel is averaging 2958 over a 5 shot string. So the difference from 14.5" to 11.5" is 44 fps. Still pretty far off from what you claimed @ 100 fps. Add the 40 fps deviation and you are at 84 fps.
4) Now, from 11.5 to 10.3 they are saying a 280 fps loss in 1.2" of barrel. Add the deviation to that and it is 324 fps! Why is that? How can you go from losing 20-30 fps of barrel from 20" to 11.5"? You can't! There is no way you can have a loss of 280 fps in one inch of barrel! And there is NO WAY IN HELL you can lose 324 fps in one inch of barrel if that ammo did not fluctuate in speeds at all. That defies the laws of physics.

I have done this same exact test a few times now. In fact we just did it a week ago with the new Hyper Clean Ammo that everyone is starting to use. We've done it with Corbon, PMC, Lake City, Federal, Eagle, Independence, simmunitions, and a plastic projo that is used in military training exercises. We build a chrono spread sheet with multiple types of ammunition to have a database and we passed what we did on to people that could use it as well. We also did the test with several different types of suppressors and manufacturers of rifles to see if there was a large difference.
 
Personally I'm not a fan of the RIS II system and decided to stick with the standard MK18 Mod 0/CQBR set up. I think the RIS II adds weight (if not real weight, perceived weight). If you don't plan on running a NV system with laser or you don't use magpul's AFG, I've found that the RIS II is just an expensive cosmetic upgrade.

This is all of course just my opinion and yours may very based on your experiences.
 
You are so close minded and basic that I am shocked you can breathe on your own. How old are those "charts"? They don't show the few key types of ammo that are in use now with these short uppers! The only one I see that is widely used is LC Green Tip.

I am saying it and will continue to say it thru experience with the weapon systems. ONE INCH OF BARREL does not matter in performance, dwell time, gas port erosion, crown erosions, throat erosion, or whatever bullshit erosion you can think of next!

What I also find ironic is the fact that you can copy and paste like a champ but not one time have you said anything about proving these theories on your own. 40-50 fps is all you will lose in one inch of barrel on an SBR once you drop below a 14.5" barrel. Add a suppressor and that changes again. A tuned gas system, changes again. See the pattern here? Then you consider the different types of barrel materials and rifling styles. A lot of factors but when it comes down to commonalities of barrel length to performance ratio…. your claims of 100 fps per inch, smoother cycling, lower dwell times, and all sorts of other rampant bullshit are quite funny. So you are the one spreading false information! Ive spent a lot of time behind a rifle and chrono trying different types of ammo so I could record what I found and have a nice data table for the types of ammo I keep on hand. I know my results are factual and proven, yours are supposedly correct because they came from the internet? Oh ok……. man you are a smart guy, congrats on your achievement. Did you get a blister from the keyboard and mouse?

I will also tell you how your chart is flawed….

Let's look at the XM193 test numbers:

1) They have their control barrel (20") putting down an average of 3165 +/- 40 fps. So that is a pretty decent ammo for this testing being that its light, fast, and for AR15 ammo the speed deviation is not terrible. A 5 shot string never even gets the barrel warm.
2) Now you drop down to a 14.5" Barrel length and it's doing 3002, so if that 40 fps deviation happened you are talking a difference of 123 fps over 5.5" of barrel. A far cry from your alleged 100 fps per inch of barrel. That equates to 22.3 fps per inch of barrel, add the 40 fps thats 62 fps per inch.
3) The 11.5" barrel is averaging 2958 over a 5 shot string. So the difference from 14.5" to 11.5" is 44 fps. Still pretty far off from what you claimed @ 100 fps. Add the 40 fps deviation and you are at 84 fps.
4) Now, from 11.5 to 10.3 they are saying a 280 fps loss in 1.2" of barrel. Add the deviation to that and it is 324 fps! Why is that? How can you go from losing 20-30 fps of barrel from 20" to 11.5"? You can't! There is no way you can have a loss of 280 fps in one inch of barrel! And there is NO WAY IN HELL you can lose 324 fps in one inch of barrel if that ammo did not fluctuate in speeds at all. That defies the laws of physics.

I have done this same exact test a few times now. In fact we just did it a week ago with the new Hyper Clean Ammo that everyone is starting to use. We've done it with Corbon, PMC, Lake City, Federal, Eagle, Independence, simmunitions, and a plastic projo that is used in military training exercises. We build a chrono spread sheet with multiple types of ammunition to have a database and we passed what we did on to people that could use it as well. We also did the test with several different types of suppressors and manufacturers of rifles to see if there was a large difference.



Once again you are smoking crack. What the blue fuck are you talking about this time?

1. WHERE is anyone mentioning a 20" barrel? What XM193 test numbers?
2. PMC Bronze 55gr 223, Radway Green 5.56, M855, XM193 and 75GR BH are all pretty representative rounds most shooters will encounter.
3. Just about every highly respected opinion in industry and the boards disagrees with you. You are just pulling shit out of your ass and backtracking, because you know you are WRONG.
4. Using a Noveske or other Poly rifled barrel as an example is not intellectually honest as we all know poly barrels tend to shoot faster than traditional barrels. Big fucking deal. Does not change wear, dwell or the fact that most Can companies won’t warranty a gun with less than 11.5" barrel. Want to take a guess why?
5. You still fail to understand that that FPS gain/loss is not linear.
6. You suck cock at math. Go take a remedial algebra class at your local community college. Follow that up with Statistics for Dummies.
7. This new Hyper clean Ammo that everyone is starting to use? Please tell us more about how everyone us using it.
8. The Ammo examples I posted are what your average shooter are going to run into. 55 and 62Gr are by far the most common rounds any of us will find on the shelf. When SOST (Mk318) and other wonder rounds are even availible for purchase let me know. The fact that there were created to bridge the gap running shorter guns with ballistic deficenies just bolsters my point.



Feel free to post your database. Post your control measures and equipment. Then show us your multiple samples of tests between 10.3/5 and 11.5 Barrels from quality manufactures and run 20K through each gun. After that, you can report the MRBF, accuracy testing, and bore/gas port wear. I am sure BCM, KAC and the rest of the industry would love to be proved wrong by some guy who can't do simple math.
 
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Personally I'm not a fan of the RIS II system and decided to stick with the standard MK18 Mod 0/CQBR set up. I think the RIS II adds weight (if not real weight, perceived weight). If you don't plan on running a NV system with laser or you don't use magpul's AFG, I've found that the RIS II is just an expensive cosmetic upgrade.

This is all of course just my opinion and yours may very based on your experiences.

The RIS is heavy, but a modern FF rail will save weight over the stock handguard setup and will allow you to FF the barrel. I am not a huge fan of the RIS either, its outdated and there are much more modern alterntives on the market now.
 
OP, if I may side step the drama, here is my experience:

I am civi, I shoot (and more importantly want to be able to shoot) any ammo I have on hand - from cheap under powered 55 grn Wolf .223, to hot home rolled 77s.

I have a 6933 and a 10.5" LMT. The 10.5" thing was a trend b/c it was purportedly what the Pros from Dover rolled with. Some day I will get off my ass and write the BATFE that I am ammending the length to 12.5", as *I* don't consider my 10.5" to be reliable enough across a broad spectrum of ammo.

Unlike the 11.5, the 10.5 required a buffer change to get it close to running with most ammo. That said, if I feed it 55 grn Wolf it will fail to extract, eventually rip a rim, and require a cleaning rod to get the case out. Now 62 grn Wolf will run fine, or 55 with a can, but not 55 and no can.

That 1" or even 2" is still short enough to be very short but IMHO adds a lot of reliability across the ammo spectrum.
 
Adding my limited experiences into the mix, I have a 10.5" Noveske Switchblock upper on my M16A1 lower, and it runs like a clock. I mostly shoot unsuppressed as the break is more effective at controlling muzzle climb than my Surefire MINI. I have experienced zero issues, mostly shoot full auto, and haven't cleaned the gun in at least 800 rounds. The brass shows zero signs of pressure or timing issues.

My experiences tend to be that the biggest differences in reliability tend to be in the quality of the manufacturer of the upper. I had read about the dramatic differences between a 10.5" and 11.5" upper, but went with the 10.5" Noveske because I wanted a switch block direct impingement shorty upper.

I have no regrets, and am sure I would have had no regrets with a quality 11.5" upper either.
 
This is directed to Cal50, the poor aspergers paitent as well:

Yet you follow me into every thread? Interesting. Truth is, you don't know shit. Your small sample and experince and not indicative of reality. People MUCH more experienced and smarter than the both of us have already figured this out and lay out the tangible difference. So you are either an idiot, or you are just arguing for the sake of arguing. You are giving shitty advice that is fundamentally WRONG while trying to be a jackass to people who are trying to help. So give it a rest. I already showed you multiple examples of why you are WRONG. You ask for a table, and I post it, then you discount it like anything else that doesn’t fit you narrative.

I sleep fantastic at night. As long as morons like you give out factually incorrect information and poor advice, I will call you out. If you want to be a dick about it and get into a pissing match, then the only person to blame is yourself. If you are too sensitive to be corrected when you are wrong, then look into another hobby like knitting or quilt making. I hear they don't like confrontation.




Oh so now it’s no MAJOR changes? I thought it was 60 FPS or less? So you two continue to post false and incorrect information that is PROVEN to be wrong, and then blow it off and won't admit you are wrong. The fact that there is a substantial change in reliability AND performance is the whole point of these posts. Next you’re going to tell me gas port erosion is the same with a 10.5 and 11.5 in barrel. Give it a break.



Don't flatter yourself.
You are similar to an asshole passed on the highway except now I know the car you drive with the vanity plate "Turdcutter".
You really are a legend in your own mind.


Like I said before you are living proof anal sex works so continue on.
 
Don't flatter yourself.
You are similar to an asshole passed on the highway except now I know the car you drive with the vanity plate "Turdcutter".
You really are a legend in your own mind.


Like I said before you are living proof anal sex works so continue on.

All this talk of anal sex, your poor little asshole must be raw and stretched out.
 
Thanks a bunch folks. I am considering shaving my front sight to run a free float tube and just enjoy the barrel I already have. Lots of good points to be considered were addressed here so thanks again!
 
Once again you are smoking crack. What the blue fuck are you talking about this time?

1. WHERE is anyone mentioning a 20" barrel? What XM193 test numbers?
2. PMC Bronze 55gr 223, Radway Green 5.56, M855, XM193 and 75GR BH are all pretty representative rounds most shooters will encounter.
3. Just about every highly respected opinion in industry and the boards disagrees with you. You are just pulling shit out of your ass and backtracking, because you know you are WRONG.
4. Using a Noveske or other Poly rifled barrel as an example is not intellectually honest as we all know poly barrels tend to shoot faster than traditional barrels. Big fucking deal. Does not change wear, dwell or the fact that most Can companies won’t warranty a gun with less than 11.5" barrel. Want to take a guess why?
5. You still fail to understand that that FPS gain/loss is not linear.
6. You suck cock at math. Go take a remedial algebra class at your local community college. Follow that up with Statistics for Dummies.
7. This new Hyper clean Ammo that everyone is starting to use? Please tell us more about how everyone us using it.
8. The Ammo examples I posted are what your average shooter are going to run into. 55 and 62Gr are by far the most common rounds any of us will find on the shelf. When SOST (Mk318) and other wonder rounds are even availible for purchase let me know. The fact that there were created to bridge the gap running shorter guns with ballistic deficenies just bolsters my point.



Feel free to post your database. Post your control measures and equipment. Then show us your multiple samples of tests between 10.3/5 and 11.5 Barrels from quality manufactures and run 20K through each gun. After that, you can report the MRBF, accuracy testing, and bore/gas port wear. I am sure BCM, KAC and the rest of the industry would love to be proved wrong by some guy who can't do simple math.

Since you don't bother to read your own posts, this is worthless to keep explaining it over and over. You provided velocities in your post of XM193. I was using it as an example. The 20" barrel numbers came from their website!
Just about every ammo you listed has similar velocities as long as bullet weight is identical. They don't change much.....
I suck at math? Now that is funny considering I work with numbers all day and you work with crayons and graph paper. I gave examples of FPS change over YOUR SCALE! You might head back to community college and take a reading comprehension course, or basic English would help. Again, all you do is fling insults, if you can't keep up just admit it.

Hyper Clean is an up and coming ammunition maker, if you left the basement once in awhile you might see these new ammo manufacturers starting to gain popularity because its readily available and runs extremely well across the board.
 
Holy necro, Batman... how did you even find this (agged) thread...?
 
Perhaps someone just wanted to watch a CobraCutter rerun.
 
No shit? That's cool that y'all were WOGS together. I remember that day all too well. I was the very last motherfucker to finish that day.

Davy Jones looked at me & he says "I'm not sure if you have too many friends or a lack thereof." My response was looking over my shoulder & saying "I'm starting to wonder that myself." If this any indication of my day, I finished w/ seven olives & seven cherries in my mouth. But, we had steak & lobster that night & I ate like a king.
 
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