So you picked up a PA10 or PAC Tac10 and are trying to figure out what parts are compatible?

Lower Parts

Magazine Release Button

The magazine release on these lowers are standard AR-15 magazine releases, threading is 10/32. Extended magazine releases seem to wiggle a bit in my PA10 lower, but they work just fine.

Magazine Catch

The magazine catch is reported to not be the same as the AR-15, the PSA LPK’s mag catch has the same threading as AR-15 LPKs (10/32)

Bolt Catch

The bolt catch is Armalite pattern

Takedown Pins

The pivot pin is Armalite pattern

The rear takedown pin is proprietary. The diameter is the same as DPMS & Armalite’s pin, however the length is the same as AR-15 rear pins

Grips

Grip is a standard AR-15 grip as well, however during assembly keep in mind that the rear takedown pin detent is not in the usual place behind the buffer tube end plate. The PA10 places the rear takedown pin detent just above the pistol grip, this doesn’t require any special fitting as the spring doesn’t go into the pistol grip like the safety selector detent does. Just keep an eye on this spring as you tighten up your pistol grip to the lower. You may have a gap depending on the grip you choose but fortunately the ERGO Grip Spacer can be utilized to take up the gap.

Magazines

The PSA AR-10 utilizes SR-25 pattern magazines, Magpul’s PMAG LR/SR Magazines work great.

Trigger Guard

The trigger guard is integrated into the lower receiver…

Trigger

The trigger is AR-15 compatible, however note that the SSA-E has fitment issues and should be avoided unless you want to modify your hammer to make it fit

Buffer Tube

The buffer tube that PSA ships with their kits is proprietary (it’s longer then standard), however you can swap it out with standard AR-15 buffer tubes. If you want to replace the stock you can, it’s a mil-spec diameter buffer tube. PSA has stated that standard rifle length tubes work fine, but they recommend using the proper 308 rifle length buffer and spring in conjunction with the rifle tube. Checkout our PA10 Buffer tube/stock write up for more information

Stock

The stock that PSA ships with their kits is easy to swap out with standard AR-15 stocks. If you want to go with a fixed stock you can, Checkout our PA10 Buffer tube/stock write up for more information on fixed stocks

Upper Parts

Barrel

The barrel is DPMS style

UPDATE: Some folks have using non-PSA barrels have had problems with rounds ejecting correctly. PSA doesn’t support any non-PSA barrels with their BCG. Buyer beware here, some folks have been just fine running different barrels and others have not.

Dust Cover

Dust cover is DPMS style

Charging Handle

The charging handle is DPMS style and can be replaced by similar .308 charging handles, known compatible are BCM AR308 charging handles.

Barrel Nut

The barrel nut is standard DPMS style

BCG

The bolt carrier group is similar to DPMS…however if you run a standard DPMS BCG the forward assist on the PA-10 does not work as they lack the serrations. There are a few folks making DPMS style BCG’s with the forward assist serrations.

Handguard

Handguards that use a delta ring will fit fine, however rails that require the barrel nut to be replaced are a no go. The PSA AR10 uppers have different heights for the barrel nut and rail then standard, handguards that are “DPMS low” are compatible as well. Midwest Industries DPMS .308 .150″ Low Handguards are compatible for example. GRG makes a couple of very affordable options as well in 15″ or 16.5″

Check out our PA10 hand guard write up for more information

Gas Block

The gas block is simply a .750 diameter gas block. Check out our PA10 gas block write up for more information