AR15 Handguard, Barrel, Suppressor Compatibility

[Mr. Whisper]

I am planning to build a 300blk upper. I want to use a 7.25" handguard with a 1.3" inner diameter, and mount a Specwar 762 with the rear of the can as close to the handguard as possible (within .25"). What barrel length will allow me to do this? Would I have enough barrel protruding from the handguard to mount the Specwar with an 8" barrel? If I didn't could I use a spacer/shim?

[MJF1911]

8" should be fine, you're going to have .4" of threads. You are going to want a little room to turn the locking ring on the Specwar.

[T-Rex]

Are you able to find a gas block to fit inside of a handguard with an ID of 1.3"?

Also, just because a company calls it a 7.25" handguard, doesn't mean the actual dimension is 7.25".

Have you tried to put one together on ar15builder?

[Mr. Whisper]

finding a gas block isn't going to be an issue because it has a channel along the top. The handguard is listed as a 7" but on the spec. sheet is says that it is actually 7.25" OAL, and I cant find an 8" barrel, or a 7.25" handguard on ar15builder.com

[Mr. Whisper]

8" should be fine, you're going to have .4" of threads. You are going to want a little room to turn the locking ring on the Specwar.

So once installed, an 8" barrel will protrude from the upper receiver 7.65" right? And the Specwar 762 suppressor only covers about half of the threads from what I have heard, is that true?

[MJF1911]

Here is a pic of my 762 Specwar mounted to give you an idea of how much you'll have sticking out.



I have an ALG Defense handguard on my 300BLK and it is 1.3" in diameter with the top channel so a Syrac Ord gas block fits fine.

[Mr. Whisper]

Thankyou. So do you think that the rear of the can will run into the 7.25" handguard with an 8" barrel, or do I need a longer barrel?

[MJF1911]

I think it'll be on the tight side but should work. You'll have about a half inch between the end of the handguard and the back of the can.

[JeffWard]

I think it'll be on the tight side but should work. You'll have about a half inch between the end of the handguard and the back of the can.

That's plenty.

I run my Omega Direct Thread on my 10.5" 5.56 barrel, with a 9.75" hand-guard (actual length). The can sits 1/4" from the guard.

As long as your barrel is 3/4" longer than your guard, you're GTG, even Direct Thread.

JW

[Mr. Whisper]

OK. Thank you so much for all the help.