View Full Version : AR build question

09-09-2010, 6:30 PM
So, I got a couple of lowers and want to configure one a little unique and have run into a problem... maybe.

I like the looks of the Rock River Arms walnut stock set with the Carbine front grip. So what I envisioned is a 20 inch stainless barrel, a low profile gas block, muzzle brake and flattop receiver.

I can not seem to locate a 20 inch barrel that will take a CAR front grip. I just am not sure I like the Rifle length front grip.

Here is a link to the furniture I am looking at: (the middle one in the pic)

Any ideas where I can find a 20" barrel in stainless which could accommodate this CAR frontgrip?

09-09-2010, 6:45 PM
Not sure if you caught it, but it mentions that you have to have a gas block that has the traditional handguard cap, those wooden grips aren't free floating.

Now I've never seen a 20" barrel with a carbine length gas system, but I have a feeling that you would into some pretty bad issues with over gassing due to the very long dwell time from when the bullet passes the gas port to the time it exits the muzzle. However I don't see some custom barrel makers couldn't make one for you, although they would probably be hesitant due to the issues inherrant in that set-up. Maybe give Hart or shilen a call and ask.

09-09-2010, 7:04 PM
Wow. Thanks for the info. This is my first build and the dwell time is not something I even considered would be a problem. Hmmm... Maybe I could go with an 18" barrel and a long brake to give the overall length I am after. Maybe I shoul just go with the long rifle front grip.

Since it is not free float, how do I know which handguard cap to get? Seems they are differend sizes. I would assume this is due to the barrel diameter and OA diameter of the front grip. Unfortunately the RockRiver picture and docs do not give me the specs for the parts.

This is so confusing and I refuse to just "settle". You know what I mean? I have not heard of Hart or Shilen, so off to do some research!

Thanks for the tip!

09-09-2010, 7:07 PM
I have not heard of Hart or Shilen

Hart won MANY benchrest championships, shillen is pretty famous...

Maybe just get a barrel blank?

09-10-2010, 9:31 AM
Ironwood designs in San Jose made the first wood AR furniture.

I would rather support him than a copy cat.

If you give him a call, he will tell you exactly what you need.

I would stick to a rifle length gas system if you want a 20" barrel.

I've always felt that carbine length hand guards look too short even on a carbine. On a 20" barrel it would look super short. Also more space to grab the handguard is always better than less.