PRS gen3 AR15 6.5 Grendel

[Tgting chief]

I have a custom built 6.5 Grendel and when I attached my new PRS GEN3 I ran into an issue. The vented mounting screw has nothing to receive it. It is supposed to be hand tightened but to what? Could use some help. Thanks

 

[bobke]

Do you have the correct length buffer tube-should be rifle length?

 

[hlee]

If mounted on a rifle receiver extension, that screw threads into the back of the extension. If mounted on a carbine extension, that screw is not needed, as the stock is held on via the compression of the clamp in the front.

 

[Tgting chief]

The extension is for a carbine. The old M16 had a nut welded to the end of the extension that you used to secured the rifle stock. I should have remembered. Thanks to all for the reminder!

 

[Tgting chief]

Allow me a follow up question... My buffer assembly/extension is for a carbine. My barrel is 20”. Will I have a problem cycling my bolt?

 

[Memberberries]

There's an easy way to find out, but you'll have to shoot it.

 

[6.5SH]

Allow me a follow up question... My buffer assembly/extension is for a carbine. My barrel is 20”. Will I have a problem cycling my bolt?

Purely depends on gas system length and port size. As long as it is ejecting at 3-4 O'clock it is fine. If ejecting forward of that try a heavier buffer.

As to any dents on case mouths it is a timing issue because of the short case length Vs 5.56. A piece of heavy duty loop side velcro on the brass deflector will minimize it, but the proper fix is to trim a coil or so off the ejector spring.

 

[hlee]

Carbine Extension ==> Carbine Spring + Carbine Buffer
Rifle Extension ==> Rifle Spring + Rifle Buffer

The bolt carrier is going to reciprocate the same length, regardless of how long the extension is. The buffer dictates where it stops- not the gas system length. If you put a rifle buffer in a carbine extension, the BCG cannot go far enough back to cycle the action. If you put a carbine buffer in a rifle extension, the BCG can go so far back that it chews up the rear end of the lower. Just make sure you are using the correct buffer length for your receiver extension and you should be fine. It is possible that you may need to play with the buffer weights, or add an adjustable gas block and fiddle with that, but you will at least have the right parts (physically) for the system to operate correctly.