• Watch Out for Scammers!

    We've now added a color code for all accounts. Orange accounts are new members, Blue are full members, and Green are Supporters. If you get a message about a sale from an orange account, make sure you pay attention before sending any money!

  • Site updates coming next Wednesday at 8am CT!

    The site will be down for routine maintenance on Wednesday 6/5 starting at 8am CT. If you have any questions, please PM alexj-12!

6.5 creedmoor SPR Build

LVMED

Sergeant
Full Member
Minuteman
Apr 22, 2013
189
2
Well I finally got all the parts together and got out to the range after loading up some test rounds last night. Nothing extraordinary but a few loads look like promising places to start.

Build was done using a :

Mega Maten Receiver set
JP Rifles 22'' 6.5 creedmoor barrel and high pressure bolt
WMD Bolt carrier
SLR adjustable gas block
PRI 15" SPR handguard and SPR top rail
Slash's Xtra Heavy buffer and spring
Sopmod stock with Sapr attachment
Geissele SD3G trigger (I love single stage triggers)
Kahles 6-24x56

Hopefully I can get her tuned for this weekend in case I feel like running it at this weekend's match in place of my DTA.

w15x0y.jpg

2ywfpdx.jpg

124hl45.jpg

2wptqhs.jpg

2qbg9ip.jpg

28vqd1f.jpg

2djo29u.jpg
 
Nice, one question though. Why the heavy buffer and adjustable gas block. In my mind they do the same thing, just from different perspectives. Heavy buffer delays unlocking and slows bolt carrier. Gas block limits amount of gas going to bolt, thereby delaying unlocking and and slowing carrier. Am i looking at that wrong, seems like u would have to let more gas through the adj gas block to counter the heavier buffer. If that's a switchblock for normal or suppresor setting then i'll be quiet lol.
 
I am looking to build a similar 6,5 ?? Upper for my armalite. I have a .308 upper already and I think it will round out the set for multiple purposes while maintaining ammo options.

Cool setup!! Nice equipment and good shooting.

One thing you might consider is to drag that thing through a precision class or two.
 
Nice, one question though. Why the heavy buffer and adjustable gas block. In my mind they do the same thing, just from different perspectives. Heavy buffer delays unlocking and slows bolt carrier. Gas block limits amount of gas going to bolt, thereby delaying unlocking and and slowing carrier. Am i looking at that wrong, seems like u would have to let more gas through the adj gas block to counter the heavier buffer. If that's a switchblock for normal or suppresor setting then i'll be quiet lol.
They are complementary. The adjustable gas block will only do so much so adding mass or spring rate to the carrier allows further tuning of the bolt timing. This seems to be especially important on ARs using the slow burn rate powders that the Creedmore likes.
 
Nice build.
What are your loads so far?

Sent from my SAMSUNG-SM-N900A using Tapatalk
 
sharps nitro, i don't follow ur logic. How do they complement each other? U actually have to open the gas up to help cycle the heavier carrier mass( heavy buffer). When i built my ar10 in 6.5 creed it was unlocking early and showed pressure signs at lower then expected charges. I talked to John Hollinger and Geoff corn about it. They both said it was overgassed, the solution was adj gas block OR heavy buffer. Both of these sharp men preferred to lower gas volume with adj gas block as opposed to putting a bandaid on it with a heavy buffer. The heavy buffer adds recipricating mass which is less then great for fast follow up shots. I ran 45.5 gr h4350 under a 123 amax in mine at 2940.
 
sharps nitro, i don't follow ur logic. How do they complement each other? U actually have to open the gas up to help cycle the heavier carrier mass( heavy buffer). When i built my ar10 in 6.5 creed it was unlocking early and showed pressure signs at lower then expected charges. I talked to John Hollinger and Geoff corn about it. They both said it was overgassed, the solution was adj gas block OR heavy buffer. Both of these sharp men preferred to lower gas volume with adj gas block as opposed to putting a bandaid on it with a heavy buffer. The heavy buffer adds recipricating mass which is less then great for fast follow up shots. I ran 45.5 gr h4350 under a 123 amax in mine at 2940.


Nice, one question though. Why the heavy buffer and adjustable gas block. In my mind they do the same thing, just from different perspectives. Heavy buffer delays unlocking and slows bolt carrier. Gas block limits amount of gas going to bolt, thereby delaying unlocking and and slowing carrier. Am i looking at that wrong, seems like u would have to let more gas through the adj gas block to counter the heavier buffer. If that's a switchblock for normal or suppresor setting then i'll be quiet lol.

My choice to use both a heavy buffer and an adjustable gas block can be summed up by F=m x a. Using both in conjunction with each other gives me optimal efficiency in regards to the impulse or Force (felt recoil) and the velocity at which the bolt is traveling when the gas hits the key (A). By using an xtra heavy bolt I am slowing the the acceleration of the bolt and carrier as the gas pushes on the key. By using the adjustable gas block I am controlling the amount of gas that hits the carrier group thus reducing the energy it travels with. This makes the force or recoil less than if I were to only use just the gas block or buffer by themselves. I also have a supressor in jail which will eventually find it's way onto the weapon, so I kinda need both for proper function.

Nice build.
What are your loads so far?

Sent from my SAMSUNG-SM-N900A using Tapatalk

Looks like I will be rolling with 38grs of Varget under 123gr SMKs and 43.5 grs of H4350 under 123gr SMKS both traveling right around 2850 fps
 
Last edited:
Nice build LVMED! Very nice set up all around.

6brshooter, you should start another thread on the adj GB/heavy buffer issue to avoid hijacking the thread. Outside of the threaded brake LV has on his rig insinuating he's shooting both suppressed and non (or at least planning on it in the future) there is a LOT more going on with any given rifle to merely assume less reciprocating mass = all that is good in the world. So much more that I'll just leave it there, but note that the cyclic rate/gas pressure/buffer/spring/carrier/gas length issue - regardless of caliber - is probably the number 1 most misunderstood aspect of a rifle, how it runs and what the perceived benefits of such components would be to the shooter in the context of what his individual goals and preferences are.

Anyway, carry on. Sweet rig LVMED...
 
My choice to use both a heavy buffer and an adjustable gas block can be summed up by F=m x a. Using both in conjunction with each other gives me optimal efficiency in regards to the impulse or Force (felt recoil) and the velocity at which the bolt is traveling when the gas hits the key (A). By using an xtra heavy bolt I am slowing the the acceleration of the bolt and carrier as the gas pushes on the key. By using the adjustable gas block I am controlling the amount of gas that hits the carrier group thus reducing the energy it travels with. This makes the force or recoil less than if I were to only use just the gas block or buffer by themselves. I also have a supressor in jail which will eventually find it's way onto the weapon, so I kinda need both for proper function.



Looks like I will be rolling with 38grs of Varget under 123gr SMKs and 43.5 grs of H4350 under 123gr SMKS both traveling right around 2850 fps

Very nice setup but i'd like to comment on the heavy buffer.

I have 2 AR308s and an AR15 with adjustable gasblocks that I run suppressed and unsuppressed so I have a good general idea of how they work. Heavy buffers/springs are designed for overly gased AR's to slow the cyclic rate/dwell time of the rifle. Generally you want to use the least amount of gas possible to reliably cycle the rifle. Since you're using an adjustable you are kind of defeating it's purpose with a heavy buffer/spring because you need to use more gas for the rifle to cycle with the heavier buffer/spring. If you notice that's why JP uses lightened bolt carriers and lightened buffers(except their newer buffer system) with their adjustable gas blocks. The less amount of mass moving at a slower speed(minimal amount of gas needed) will translate to less felt recoil.
 
Last edited:
I would ditch the heavy buffer and go for a lighter setup that will also drop your felt recoil. Use the gas block to adjust the rifle.
 
Not trying to hijack, just wanting to understand/learn something. I don't have suppresors in Il so i wouldn't know about their cyclinhg issues. Inked and Kys are on my same wavelength, they put it better then me actually. Irregardless, OP very nice rifle. Good day gents
 
I would ditch the heavy buffer and go for a lighter setup that will also drop your felt recoil. Use the gas block to adjust the rifle.

Very nice setup but i'd like to comment on the heavy buffer.

I have 2 AR308s and an AR15 with adjustable gasblocks that I run suppressed and unsuppressed so I have a good general idea of how they work. Heavy buffers/springs are designed for overly gased AR's to slow the cyclic rate/dwell time of the rifle. Generally you want to use the least amount of gas possible to reliably cycle the rifle. Since you're using an adjustable you are kind of defeating it's purpose with a heavy buffer/spring because you need to use more gas for the rifle to cycle with the heavier buffer/spring. If you notice that's why JP uses lightened bolt carriers and lightened buffers(except their newer buffer system) with their adjustable gas blocks. The less amount of mass moving at a slower speed(minimal amount of gas needed) will translate to less felt recoil.

Makes sense. I'll pick up a regular DPMS buffer to try out. I am a chemist by training so if I f&*ked up the physics I apologize lol.
 
Not really. Why then does David Tubb make a carrier weight system? Or why would the SCAR17's recoil be so mild with its massive reciprocating mass? Why would PWS make an enhanced DI AR15 carrier that's nearly equivalent to a standard M16 with CWS installed? Because it increases felt recoil? I simply, but respectfully, disagree that using the lightest buffer available is best in all cases or that it correlates to softer/less/smoother recoil regardless of caliber or the rifle's specific characteristics.

I see the benefit of lightweight carrier and buffer combos along with an adj GB being geared towards speeding up cyclic rate (albeit doing so with the least amount of recoil possible) for fast follow up shots in your 3 gun set ups rather than smoothing out the recoil impulse. I'm not saying to use the heaviest buffer available, but I wouldn't consider using a 6.5oz buffer - that's only an ounce heavier than a standard Armalite carbine buffer - a real big deal. IMO, It'll actually give you more margin of error with respect to how smooth it will shoot with different loads and switching back and forth from suppressed to non etc.

I prefer my bolt stay locked in chamber as long as possible for a few reasons. Brass is in FAR better shape, and gas is utilized pushing the projectile. A heavy buffer (or heavier than std weight for whatever platform & caliber) will noticeably increase lock time. How heavy you go would depend on gas port location, size, and how much barrel length you have forward of the port. Those aspects, along with your carrier weight and it's length of travel will ultimately dictate how heavy your buffer needs to be. If you're running a std 7" buffer tube it's difficult to not only decrease the velocity your carrier is moving rearward, but more so to time the cycling of the gun appropriately and ensure the gun itself it absorbing as much of the energy transfer from the recoil as possible. A heavy buffer certainly helps absorb more of that energy than would a lighter buffer - and becomes a huge plus when shooting suppressed.

Just because you're using more gas to push more weight doesn't mean there's anymore recoil. Redirecting gas is important, but the adj GB isn't a black hole where gas just disappears. It's going somewhere. If you're using more gas to push a heavier reciprocating mass you would then have less exiting the muzzle implying you'd have a reduction in muzzle blast and, hence, less muzzle rise.

The point should be to use any and every tool at your disposal to use the gas created from 'X' grains of powder pushing 'Y' bullet at 'Z' velocity in the most efficient way possible while BALANCING where and how much gas you need to use for various operating mechanisms to function as close to perfect as possible.

The process of balancing gas dispersion in a consistent, repeatable fashion can vary dramatically depending on powders being used (volume, burn rate, etc), application specific variables (hunting vs comps - bullets being used, minimum velocity thresholds related to terminal performance, etc), suppressed/non-suppressed, along with an individual's preferences related to how he/she prefers a rifle to shoot that might change how one distributes gas to effectively manage things like recoil impulse, cyclic rate, and reliability across that spectrum of ever changing variables. A heavy(ier) buffer - in conjunction with an adj GB - have always been crucial to getting my rigs right where I want them.
 
Last edited:
Not really. Why then does David Tubb make a carrier weight system? Or why would the SCAR17's recoil be so mild with its massive reciprocating mass? Why would PWS make an enhanced DI AR15 carrier that's nearly equivalent to a standard M16 with CWS installed? Because it increases felt recoil? I simply, but respectfully, disagree that using the lightest buffer available is best in all cases or that it correlates to softer/less/smoother recoil regardless of caliber or the rifle's specific characteristics.

I see the benefit of lightweight carrier and buffer combos along with an adj GB being geared towards speeding up cyclic rate (albeit doing so with the least amount of recoil possible) for fast follow up shots in your 3 gun set ups rather than smoothing out the recoil impulse. I'm not saying to use the heaviest buffer available, but I wouldn't consider using a 6.5oz buffer - that's only an ounce heavier than a standard Armalite carbine buffer - a real big deal. IMO, It'll actually give you more margin of error with respect to how smooth it will shoot with different loads and switching back and forth from suppressed to non etc.

I prefer my bolt stay locked in chamber as long as possible for a few reasons. Brass is in FAR better shape, and gas is utilized pushing the projectile. A heavy buffer (or heavier than std weight for whatever platform & caliber) will noticeably increase lock time. How heavy you go would depend on gas port location, size, and how much barrel length you have forward of the port. Those aspects, along with your carrier weight and it's length of travel will ultimately dictate how heavy your buffer needs to be. If you're running a std 7" buffer tube it's difficult to not only decrease the velocity your carrier is moving rearward, but more so to time the cycling of the gun appropriately and ensure the gun itself it absorbing as much of the energy transfer from the recoil as possible. A heavy buffer certainly helps absorb more of that energy than would a lighter buffer - and becomes a huge plus when shooting suppressed.

Just because you're using more gas to push more weight doesn't mean there's anymore recoil. Redirecting gas is important, but the adj GB isn't a black hole where gas just disappears. It's going somewhere. If you're using more gas to push a heavier reciprocating mass you would then have less exiting the muzzle implying you'd have a reduction in muzzle blast and, hence, less muzzle rise.

The point should be to use any and every tool at your disposal to use the gas created from 'X' grains of powder pushing 'Y' bullet at 'Z' velocity in the most efficient way possible while BALANCING where and how much gas you need to use for various operating mechanisms to function as close to perfect as possible.

The process of balancing gas dispersion in a consistent, repeatable fashion can vary dramatically depending on powders being used (volume, burn rate, etc), application specific variables (hunting vs comps - bullets being used, minimum velocity thresholds related to terminal performance, etc), suppressed/non-suppressed, along with an individual's preferences related to how he/she prefers a rifle to shoot that might change how one distributes gas to effectively manage things like recoil impulse, cyclic rate, and reliability across that spectrum of ever changing variables. A heavy(ier) buffer - in conjunction with an adj GB - have always been crucial to getting my rigs right where I want them.

Lighter parts(bolt carrier, buffer, etc) will increase cyclic rate when compared to normal or weighted parts if the amount of gas feed to the bolt carrier is the same in all cases. The benefit of using lighter parts with an adjustable gas block is that it takes less gas to cycle the rifle with the lighter parts but will not decrease what you refer to as "lock time" or increase the velocity of these moving parts because the gas can be adjusted to the minimum amount needed to cycle the rifle. So if you are moving more weight rearward at the same velocity the end result will be more recoil(perceived or not) . You can not accurately compare a PWS gas piston system and the SCAR to a DI system because they do not operate the same.
 
Last edited:
Makes sense. I'll pick up a regular DPMS buffer to try out. I am a chemist by training so if I f&*ked up the physics I apologize lol.

That would be my advice. Just try the stock buffer and spring and set the gas block to it's lowest setting. Decide for yourself which you like better... All 3 of my gas blocks are SLR and I adjust mine by loading a single cartridge and closing it a click(quarter turn) at a time per shot to see if it engages the bolt catch until it no longer does then opening it back up a click(quarter turn)or you can start with the gas block closed and do one shot per click until the bolt locks back. Just remember to feed the individual rounds from the magazine. This will be load dependent of course as different loads produce different pressures(example your bolt may lock open on a 140gr handload but not on a 120gr factory load)..
 
Last edited:
The gas that doesn't go through the adj gas block goes out the loud end of the rifle. As i mentioned my creedmoor showed ejector marks on lower pressure loads. Talked to white oak and corn about it, both said it was early unlocking(overgassed) and layed out my two options: adj gas or heavy buffer. Both guys preferred cutting gas down to alleviate this. I adjusted open the gas until it just locked bolt back on empty mag+1/8 turn more. I could then get another 75-100 fps without ejector swipes. I could close the gas all the way to where the bolt just bumped back an inch or so. Scar has a very good brake, ask scar owners how they love that heavy bolt with optic breakage.
 
Right. Like I said, the less gas you have pushing your BCG through a cycle the more you have exiting through the end of your barrel. Shooting suppressed, I very much prefer using a heavier carrier and heavier buffer using a proportionately equal amount of gas to move that heavier weight thereby decreasing the gas pressure exiting the muzzle (which is this example has a can on it). Doing so significantly increases the attenuation and overall performance of the can. Additionally, it lengthens the duration of the recoil impulse, more energy is absorbed by the heavier/longer parts assisting in the operation of cycling the action, and balances the entire life cycle of a single recoil impulse over a larger percentage of the rifle. That results in a "smoother" or "softer" - or however you want to describe it - perceived recoil (all other factors held constant).

I don't need to talk to White Oak or anyone else. I get it. If someone posed a question asking should I do A or B, rather than A AND B, I suppose I would also suggest an adj GB.

I have owned a 16" SCAR17, sold the upper for a 13.5" which I am currently waiting on. I do also understand that people have had issues with optics breakage. I have no hard data what mounts were being used, what specific optics were breaking, etc. I have had no such issue with mine.

......and commence derail...
 
Just an addendum, I got the DPMS carbine buffer and played with it but in the end I prefer the heavier buffer. All that aside 38gr of Varget is definitely the load I will be moving forward with.
97880p.jpg

30w9ixi.jpg
 
Nice shooting. Might some of our homeboys buy a heavy buffer to compare in their rigs with adj gas? Time will tell I guess.

?