Completed AR10 Builds (6.5 Creedmoor)

[3800fps]

I don't understand, you legod not fancy parts together and it shoots boringly well… what exactly are you disappointed in?

I'm not disappointed in how this build turned out per se….it's more about "what am I going to do with a 10# semi auto platform" in a specialty caliber…I'm never taking it hunting, I don't compete…I literally have 2 dozen or more bolt action rifles all of which I glassbedded and tweaked loads for…. I don't know the exact number of AR15s but 5-7 sounds close…My point is I have plenty of guns.

This AR10 creed seemed like a good idea at the time…I thought I'd be more enthusiastic about it than I am…I'm probably just spoiled.

 

[ARlife4me]

I'm not disappointed in how this build turned out per se….it's more about "what am I going to do with a 10# semi auto platform" in a specialty caliber…I'm never taking it hunting, I don't compete…I literally have 2 dozen or more bolt action rifles all of which I glassbedded and tweaked loads for…. I don't know the exact number of AR15s but 5-7 sounds close…My point is I have plenty of guns.

This AR10 creed seemed like a good idea at the time…I thought I'd be more enthusiastic about it than I am…I'm probably just spoiled.

I understand for sure! The creed is a good round, but go with the 260rem and you'll love it! I initially bought the creed because I like the 26cals, then later found the 260rem. With the magpul m118 mags (I've heard the gen2's also have the same) getting coal to 2.830" has an advantage.

 

[bamban]

Where can you get a dingleberry hone this size? The cheese grader sound does make me think "cheap" so yes it's just a pet peve.

Brake cylinder hone works great for the purpose.

 

[ARlife4me]

Brake cylinder hone works great for the purpose.

The master cylinder or the wheel cylinder, yes.

 

[bamban]

The master cylinder or the wheel cylinder, yes.

I use it to hone the buffer tube after I bore it to accommodate the AR15 BCG anti-tilt sleeve mod.

 

[Carl Gustaf]

Sprinco

Sprinco AR tuning page

When an H3 buffer is routinely on sale for $30ish, it's probably easier and cheaper, weight is but just factor. The correct length is just as important. You want 5/16" - 3/8" between the bolt catch and bolt face when it is in the rear most position.

Test it with your spring removed and your upper off.

Once I was convinced to tune using a spring and buffer, I never purchased another adjustable gas block. Much smoother and less finicky. I was told reducing the one thing that cycles the bolt was crazy, hard to adjust the gas block in a SHTF scenario. I just took it and applied it to every rifle I built. I also open up the gas port if required, just a few .001"s at a time, but I have only had to do a couple.

I just threw together a 6.5 and it is terrible...
Pops primers.
Ruins brass.
I have no idea what to do?
Bear creek upper/ Palmetto state multi lower.

 

[Darryle]

Wrong bolt, wrong load data

It's slamming the brass back into the chamber I bet, up the buffer weight, minimum of an H3, buy the correct next heavier buffer spring

you need a small firing pin bolt of good quality

This is all a wild *** guess unless you list exact components of the build, brands of preferably, length of gas system and ammo being used.

 

[rpol98]

I just threw together a 6.5 and it is terrible...
Pops primers.
Ruins brass.
I have no idea what to do?
Bear creek upper/ Palmetto state multi lower.

I'm guessing you don't have a HP bolt with the skinny firing pin, highly recommended for 6.5CM, not as much for 308 (but doesn't hurt for 308). Is this with factory ammo?

barrel length? gas system length?

and further guessing, that you're using a default 3oz (or 3.8oz) buffer (if carbine buffer tube). That's a little light for AR-308 usage, if that's the case. Hopefully you got the buffer tube depth, buffer length compatibility squared away, able to lock the bolt back behind the bolt catch.

A heavier buffer would probably benefit you, and an adjustable gas block also. I'm kinda surprised that the BCA upper works with the PSA lower, due to the known misalignment of the bore axis, upper vs lower. PSA went their own way, compared to the rest of the LR-308 market. You're probably getting some impacting of the bolt carrier at the entry to the buffer tube? or scuffing at the front of the buffer tube? Unless BCA uses the PSA bore axis height, but I thought BCA used the DPMS-pattern LR-308 bore axis height.

 

[3800fps]

I just threw together a 6.5 and it is terrible...
Pops primers.
Ruins brass.
I have no idea what to do?
Bear creek upper/ Palmetto state multi lower.

Without hands on your gun none of us can say for sure what the specific issues are…but Bear Creek is a huge red flag to me…

Any lower is basically just swinging a hammer at the firing pin so the Palmetto stuff should be ok (if you can tighten the upper to the lower)Aero lowers have an adjustable screw tightener built in…gotta have a heavier buffer and spring for the heavier BCG.

I hear and read lots of complaints about Bear Creek products …I have an AR 15 heavy stainless barrel they made…cannot be made to shoot under 2moa…it's now part of a wind chime I'm working on.
Contact Bear Creek cuz blown primers sounds like a headspace/ chamber spec issue.
Like others mentioned the cheaper BCG and bolt head itself may not be up to 6.5 CM snuff.

 

[Carl Gustaf]

Thanks for your input. Ordered these and hope they will fix the problem.

 

[Bullitthead]

Not all barrel mfgs are equal when it comes to gas system lengths. Aero Precision is the only 1 so far that is 100% good from the git go on standard rifle length gas. I have a cbi (criterion?) that has rifle length, but pops primers (I'll need to do some more adjusting). That barrel is a tac driver for sure! Proof barrels in SS and CF with +2 aren't near as good with function (needs more tuning). I have Faxon, 2A and 1 more brand (I'll get back to you) that's not near as good as the 1st 2. With AP I run standard weight buffer, spring and non-adjustable gb and it runs flawless! What I don't like is the 4.5-5# barrels, but now offer fluted that might save 6-8oz. Gas port size is very important as AP has it nailed! All of these have been tested with Hornady 120 a-max factory ammo. I also have 260rem barrels from PR also that has the same issue, but I'm working it out. Most have agb and vary on gas system length (standard to +2 rifle). Fixes will be a heavier buffer and maybe a stronger spring for better function. I also don't have or run any suppressors.

Mine was stamping primers. I had to get a JP high pressure bolt to stop it.

 

[Darryle]

Thanks for your input. Ordered these and hope they will fix the problem.

Carl, take this as constructive and not to heart.

My first large frame AR experience was about like yours, many years ago.

There are just no rules to the large frame AR patterns, hence @3800fps comment. Everyone just does what everyone wants with a few basic guidelines.

You have a multitude of issues, cycling is just one, a gas block and silent spring isn't going to correct blown primers, it might, but I bet it doesn't.

You have a cyclic issue, the bolt is coming out of battery way to soon, and the torn up brass is just one part of the evidence, blown primers are another.

You are probably experiencing failure to lock back and failure to pick up the next round occasionally, further evidence.

An H3 buffer is $35ish most places plus shipping, a Sprinco "Red" heavy recoil spring is $23ish plus shipping from Sprinco. No adjustable gas block needed. You have full gas and can still control your cyclic rate. If those improve the performance but do not 100% correct it, you are headed in the right direction.

Diagnosing these issues with large frame ARs is not easy without having your hands on it, mainly because of the loose rules regarding specs of every part.

We'll walk you through it, it may take time and money, but in the end, you will have a 100% reliable weapon.

A little tip, only change one thing at a time and document everything with data and pictures. It will help the members here help you more efficiently.

Once it's running, the smile on your face after the first mag dump will erase all of the headaches.

You would be better served with a thread of your own, instead of you and the members trying to help don't have to wade thru this thread.

 

[ARlife4me]

Without hands on your gun none of us can say for sure what the specific issues are…but Bear Creek is a huge red flag to me…

Any lower is basically just swinging a hammer at the firing pin so the Palmetto stuff should be ok (if you can tighten the upper to the lower)Aero lowers have an adjustable screw tightener built in…gotta have a heavier buffer and spring for the heavier BCG.

I hear and read lots of complaints about Bear Creek products …I have an AR 15 heavy stainless barrel they made…cannot be made to shoot under 2moa…it's now part of a wind chime I'm working on.
Contact Bear Creek cuz blown primers sounds like a headspace/ chamber spec issue.
Like others mentioned the cheaper BCG and bolt head itself may not be up to 6.5 CM snuff.

I used to think the same thing, but it's not entirely true about headspace and chambers being that issue. I've found out that gas port size is the bigger issue! I know this by having several different manufacturers and gas system lengths in 6.5creed, 243win and 260rem. AP has been the only mfg with port size with standard rifle length system without an agb, standard recoil spring and buffer weight to run 100% without 0 issues from the start. Most of their barrels state port size and not all of their barrel lengths (same cartridge) are the same size. With the +2 gas it has taken a heavier buffer in PR barrels. It's not needed to have a 5+ oz buffer for 6.5creed, but might be required to function properly.

 

[3800fps]

I used to think the same thing, but it's not entirely true about headspace and chambers being that issue. I've found out that gas port size is the bigger issue! I know this by having several different manufacturers and gas system lengths in 6.5creed, 243win and 260rem. AP has been the only mfg with port size with standard rifle length system without an agb, standard recoil spring and buffer weight to run 100% without 0 issues from the start. Most of their barrels state port size and not all of their barrel lengths (same cartridge) are the same size. With the +2 gas it has taken a heavier buffer in PR barrels. It's not needed to have a 5+ oz buffer for 6.5creed, but might be required to function properly.

I am by no means an expert on gas gun function and tuning…but like Darryle stated "there's no rules" and 2 distinct 308 patterns…

I chose the Aero enhanced upper for the true free float feature and matched to an Aero lower, BCG, and gas block…guessed on the buffer weight and expected to have to buy an adjustable gas block.

I got lucky every thing flows and the Brownells barrel (looks like a Faxon) and gas port size worked out perfectly.

Chasing down Carl Gustaf's issues might get a little costly buying things twice but it'll get fixed.