a couple questions about ar muzzle devices

[reed1285]

ok, so first question. I bought a YHM phantom muzzle brake a few months ago to install on one of my ar15's. Well I was going to install it tonight because im getting tired of looking at it sitting on my gun safe. I searched around, and looked at a few youtube videos on how to do this, because I just wanted to make sure my assumption of just unscrewing the old one off, then screwing the new one on (with a new crush washer of course) was right. Well in the few vids I watched on youtube, they all talked about "indexing" the muzzle brake. How do I do this for my YHM phantom? The ones I watch all dealt with the battlecomp brake, which has a mark on the brake to help with indexing. I looked on mine and couldnt find any marks to help with indexing it. Do you only have to index certain ones? Or should they all be indexed? I also searched google specifically for a YHM phantom brake install, with no luck. I know to some this may be a mundane task, but its the first one I will be doing, so help will be appreciated.

 

Second question. The brake i specified above is going on my 16" barrel ar. I have another ar with a 14.7" (palmetto) upper, with a permanently pinned a2 flash hider on it. All this searching and talking about muzzle devices got me to thinking. If I take the upper off the rifle, would it be legal for me to take the flash hider off of it, replace it with one of my choice, take it to a gunsmith to have it pinned, then put it back on the rifle?

Again, I understand that without that pinned flash hider on there, I would technically have an SBR upper. Thats why I would not put it back on the rifle until the new flash hider was pinned. And yes i realize removing a pinned flash hider would be a pain in the a$$. Im just wanting to know if doing it like that would be legal.

 

Someone help me out with these 2 questions. Thanks in advance.

[c.a.willard]

Id recommend with the 14 1/2 barrel just taking to a gunsmith and having them romove it  then install and permanently pin the new one.  Mainly just due to the PITA nature of removing the pin but it also helps to avoid any NFA legal issues.

 

Most muzzle brakes need to be indexed somewhat but not necessarily precisly.  Not sure wich YHM you have but most have 5 ports for the flash/muzzle blast.  Allign it so that the center port is at the 12 oclock position.

Edited January 14, 2013 by c.a.willard

[RWF]

put the solid part of the brake on the bottom. think what would happen shooting prone. with the holes pointed at the ground

[alwaysonjohn]

With the battle comp the logo or the side without the holes needs to be pointed down. Indexing basically means tightening till the brake gets aligned perfectly. Some brakes and flash hides don't get aligned as they continue the design and ports throughout the brakes where the battle comp places no ports on the bottom claiming this helps with muzzle rise since all the gas goes up or left or right pushing the muzzle back in place after shooting

[alwaysonjohn]

As for pinning or unpinning you do need a gunsmith with the right tools. Don't do it yourself and screw up your barrel or you'll have a heck of a time finding a barrel any time soon. If you can't find a gunsmith that can permanently pin a muzzle device then ship it off to Adco.

[reed1285]

With the battle comp the logo or the side without the holes needs to be pointed down. Indexing basically means tightening till the brake gets aligned perfectly. Some brakes and flash hides don't get aligned as they continue the design and ports throughout the brakes where the battle comp places no ports on the bottom claiming this helps with muzzle rise since all the gas goes up or left or right pushing the muzzle back in place after shooting

So does that mean, since my phantom muzzle brake has evenly spaced ports all around it, that it does not need to be indexed?

[alwaysonjohn]

Post pictures of it. If it has little holes over all the sides then it doesn't need to be indexed. If it has large holes on only two sides then it is normally indexed so the two sides with holes point left and right.

[peejman]

Basically, you do not want any holes pointed straight down.  It'll throw up dust when near the ground.  You do want as many holes as possible pointing up.  That helps reduce muzzle rise. 

 

Swapping out a "permanently attached" muzzle device without the proper tools and skills is a recipe for disaster.  I you've never done one, get help.