Looking for large frame build advice

[RHutch]

I’m currently collecting parts to build a 16” 308 AR and need direction on a couple items.

This is my first all-in AR build (I’ve built a couple 556 lowers but never an upper)and I’ve read and read here and other lesser sites trying to educate myself.
Had an SP10 in 308 which was a fine rifle but a bit long suppressed and too heavy to enjoy hunting with.
Hoping to come in at 8 to 8.5 lbs. rifle only before optics. will be suppressed, used primarily for hunting and banging steel occasionally.

Here are the parts I have or en route at the moment:
Zev large frame billet receiver set
Zev 14.6” handguard
Criterion 10T 16” rifle gas with headspaced JP bolt
SA adjustable gas block with appropriate rifle length gas tube
LaRue MBT trigger

Questions are,
What RE, buffer and spring do I need?
Do I need to get a JP carrier since I have a JP bolt?

Any other tips to get me to the finish line, in meeting my build goal?

Thanks All

 

[wade2big]

If you want an adjustable stock:
Purchase a VLTOR RE-A5 receiver extension.
H3 carbine buffer
Any .308 rifle length recoil spring.

Done.

 

[PusherX11]

Great set of parts to start.

No you do not need a JP carrier for your JP bolt. To keep weight down the JP low mass carrier is fought to beat.

I personally run the silent capture spring form JP in all my gas guns. The gen 2 308 you can change out the weights for tungsten for a heavier buffer, also they have a spring kit.

 

[wade2big]

Many rifle length gassed .308 barrels require a longer gas tube than a standard AR15 rifle length gas tube. Been there done that. You may have to find a 15.5” gastube which is about 5/16” longer than an AR15 gastube. If you make this mistake your rifle won’t cycle.

 

[RHutch]

Good call on the gas tube as I’ve read that. I’ll double check the length when it lands. Ordered as an add-on directly from Criterion with the barrel and bolt.

 

[UpSideDown]

8-8.5lb is a standard weight for an AR-10 without glass, that’s not really a lightweight build but it’s easy to do. In large frame guns the easiest place to lose weight is the barrel, BCG, receivers, handguard and stock. Lightweight receivers are almost impossible to find right now. Handguards from 2A Arms or Smoke Composites are very light. A LMOS bcg from JP knocks 4 ounces off regular weight; a titanium bcg knocks 7 ounces off.

 

[RHutch]

Those Smoke hand guards look interesting. Looking into that as an option.
While I’m not trying to make an ultralight rifle, knock off a few ounces here and there add up….both in weight reduction and increased cost dammit.

 

[UpSideDown]

An advantage to a carbon handguard is that you aren’t touching metal when you’re hunting and it’s cold. But yeah when you’re spending about $50/ounce of weight loss on a gun, I think that unless you’re building one from the ground up instead of replacing parts you already have, it’s better to just spend some time in the gym and deal with a 10lb gun.

 

[RHutch]

10lbs isn’t a problem. Many of my bolt guns weight that.
13 - 14lbs is what I’d like to avoid.

 

[UpSideDown]

Any AR-10 with a general lean towards keeping weight down will be about 10lb with a scope.

 

[Jsp556]

The 16” rg criterion barrel uses a standard ar15 rifle length gas tube.