I was interested in an AR-308 build or a 6.5 Creedmoor AR and got some horror stories elsewhere about builds giving people lots of trouble. The issues were specifically with not cycling. Most of the trouble would come from mixing parts from different manufacturers, which I've come to understand now being risky because there isn't such a distinct specification for other calibers like there is for an AR-15. But I heard that about complete Aero Precision rifles that weren't cycling right. I don't see people complaining about this with builds on, say, YouTube. Whatever company is being featured in a video had some hand in it beforehand so I can't necessarily just go on that. On here, I would have expected to see a sticky about it or otherwise seen some people complaining about it. But it's pretty quiet here. So did I get outdated information? Did all the companies get their act together? Or did I just get some strange information in the first place? Were people just going wild with bullet grains?

Either buy a complete rifle from a reputable manufacturer or build from DPMS patterned parts.  It really is not too difficult to get it right, but you may have to tweak it to get it to run just right.

Seen and heard many horror stories.  The common theme was mix matching parts to save money.

BIL picked up franken-build 6.5 Creedmore.  I have no idea who did the barrel, upper, lower or LPK, but he had nothing but problems and not sure if he ever did really get them sorted out.


I'm a Armalite B pattern guy.  

Had failures to fire because the ammo was shit.  Had failures to cycle while tuning the gas for a can.

This.   Also, interestingly enough, 6.5CM runs in semi-auto quite reliably, FWIW.

I've built one from parts and bought one assembled (LR308) but except for the barrel it's been rebuilt with different parts. I would always suggest that for large frame AR's that if you're building one you go with the same manufacturer for both upper and lower. Other than that the primary thing that will probably require some tuning is your gas system. That would include the everything from the gas port in the barrel to the bolt.

The LR308 was way over gassed until I changed out the gas block to an an adjustable one and got it tuned for the ammo I use.  The other one (Aero  Precision U+L) has all different other parts. The only issue I had to deal with was a failure to extract and that was traced to a missing inner extractor spring - which the manufacturer happily supplied me with.

I think you need to expect to do a little tweaking or troubleshooting if you build your own. If that's not something you want to deal with buy a complete rifle.

My 6.5 parts gun on M5 receivers has not had any issues. Select quality parts and have somebody competent put it together, and it's a breeze to make a rifle that's every bit as good as what the manufacturers are offering as complete packages, and it will be tailored to your requirements.

I've used all Aero parts (except for Faxon barrel on one and SLR AGB on the other) to build two of them and the reliability has been excellent once I got the gas dialed in.  As others have said, just stick with the same manufacturer of parts and pay attention to what you are doing.  I'd much rather build than buy and cost has nothing to do with it.  Good luck!

LR .308 runs perfectly with a 16" rifle gas barrel
and standard gas block.

Ejects 3-4 o'clock with no hiccup using cheap off the shelf ammo.
I did have my SLR adjustable GB installed. I first wanted to know
how that setup would do in that config. Works great.

I used Aero receivers and their parts kits. No issues at all.

Add: Aero is DPMS pattern and their LPK and UPK should be
used. They have threaded pins and their bolt hold.

This has been my experience as well.  I have about 1800 rounds through my factory DPMS, and I do not recall any gun-related failures.  There were two instances where I chambered a round and then had to extract said round because of range cease fires and left the bullet stuck in the lands, but that was my reloading issue, not a feed or extraction issue with the gun.  I've used both factory DPMS and Midway AR Stoner mags exclusively, for what that's worth.  

The only other gun I have that appoaches that level of reliability is a home-built 5.56 AR using a BCM 11.5" tube.  I don't recall any failures with it, but it has probably less than a quarter of the number of rounds down the pipe as my Creedmoor.