I'm planning to build an AR10 for precision/long range shooting. I'm undecided on .308 vs 6.5 Creedmore. I have my Victor .308 for short distance. I've read there are two forms for AR10s. Any advice on a build? Barrel length, gas systems, etc? I'm entirely unfamiliar with doing this. I'm looking at a heavy stainless 24" barrel but open to other ideas. I know precisely nothing about gas systems.
AR10 build
- Thread starter benstt
- Start date
TEXASforLIFE
SAINT
Aero Precision! Can't go wrong with their 6.5CM. Their gas port is perfect even with standard rifle length system. The barrel at 24" is going too be about 5.5 to 6 lbs. That's if you can get 1? The 18" and 22" I have are excellent! I tested them with Hornady 123 max and sst. Both cycled perfect. I even have 2 Proof Research barrels with +2 length gas system ( steel 22" and 24" CF) and AP beats them. I will say if you can find a CBI barrel in 6.5 the accuracy is great also ( first 2 rounds almost in the same hole at 100 yards).
TEXASforLIFE
SAINT
BTW, when I called Hornady they asked me about the ammo and I told them it was incredible. This was 4 years ago.
Armalite's more popular SR style mags work in DPMS receivers which takes the the LR style.
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Aero is probably the most easy LR-308 to source parts for. The Aero M5 uses a DPMS rear cut receiver and has the DPMS style barrel nut threads which makes it really easy to find parts for.
Most AR-308 receiver sets a few proprietary parts that aren't compatible with other receiver sets such as the take down and pivot pins.
You can find complete Aero M5 upper receivers on Optics planet for in the $500-$600 range to make the project a little bit easier. If you prefer to build a upper you will need a reaction rod for .308 or 6.5 Creedmoor that will cost you at least an additional $120.
For another option you can checkout Diamondback arms website for receiver sets and all the parts to build a complete rifle. Diamondback uses an ArmaLite style slant cut at the back of the receiver but they use a DPMS style barrel nut thread.
TEXASforLIFE
SAINT
In 308win I have a CBI barrel 22" m118 chamber that's real good. The only ammo I shot in it was 147fmj white box.
To clear up some confusion with my post the ArmaLite AR-10a uses a SR-25 style Pmags.Armalite's more popular SR style mags work in DPMS receivers which takes the the LR style.
The SR-25 rifle is made by Knights Armament.
TEXASforLIFE
SAINT
If you're tuning ammo then get an adjustable gas block. Most heavy/bull barrels will have a .936" or .875" journal depending on taper. There are few makers that make longer than 24" depending on what you want to spend? I would say stay away from CF barrels all though they're some good manufacturers out there. Barltein (?) Could make a twist gain that produces higher velocities due too slower twist starting point. Say you need a 10/1 to stabilize then you could get a 11.25/1 start or a 9/1 to a 7.5/1 in a 6.5mm. A pmag gen3 (m118) gives you a 2.830" coal and is beneficial for 260rem over 6.5cm for heavier/longer bullets. I get more velocity in my 22" 260rem than in the 24" 6.5cm. You have more case capacity in the 260 when seated longer. You could get a 7mm08 also if a fan? From Barltlein it's goin to be $1,000 for a SS barrel or more?
bigx5murf
Elite
I've built 2 AR10s using PSA parts, one in 308 one in 6.5CM. Try sticking to one supplier for as much stuff as possible, to avoid incompatibilities. There's also little things that although compatible, don't look right, like many beaver tail pistol grips won't be flush with lower. Also some lowers/uppers from different manufacturers are functionally compatible, but the fit leaves massive ledges. Buffer tubes are often longer as well, so AR15 stocks will have a gap when collapsed. There's also 2 heights for hand guards, but I think the low shelf is mostly being phased out. Definitely get adjustable gas blocks, especially if you're going to suppress. I originally built my 308 without one, and the recoil was violent, and would sometimes double feed when suppressed.
I haven't been shooting my 6.5CM as ammo costs are still kinda high. 308 didn't inflate much during covid shortage, while 6.5CM reached a ridiculous $3/round.
I haven't been shooting my 6.5CM as ammo costs are still kinda high. 308 didn't inflate much during covid shortage, while 6.5CM reached a ridiculous $3/round.