Compensator

[Booyah]

I am thinking about buildind a Compensator for my AR.   I cant find any one that has one to fit my barrel.  It has a 1/2" x36 pitch barrel thread and it is a 7.62x39 chamber.   Does anyone know what the bore size should be.  Rock River Arms said that .055 over the bullet size was the standard.

[Nobade]

You are sure it is 36 TPI? Standard for an AR is 1/2X28. As for bore, got .030" over bullet diameter and make sure it's cut straight. (And you can't see the brake from the chamber end through the bore).

[Booyah]

1/2 x 36 pitch is what the threads are on my barrel.  Thats why I am having a hard time finding a compenssator.    7.62 x 39 barrels dont use the same thread as a 223     Barrel chambered in 308 are a 5/8 thread.   Bushmaster told me that a 1/2 x 36 pitch is what they put on 9mm barrel but Bushmaster told me that they didnt make compensators with this thread.    I made one and I am taking it to the range today to see how it works.  I will post once I get to try it out.

[slimjlm]

Check these out if yours doesn't work as well as you'd like, the bore is for 9mm (0.054" over your bore), so will be about twice recommended, but will probably still work fine. 

http://www.practicalpage.com/index.php?act=viewProd&productId=47
http://www.brownells.com/.aspx/pid=27072/Product/AR_15_M16_SPACE_COMP

Hope yours works though, it's always better to build it yourself!!

[Booyah]

All the Compensators that I found with the 1/2 x 36 threads are for 9MM which is oversize for the 7.62x39     I made mine and took it to the range to see how it works and I am very pleased,  I have basicly no muzzle rise at all.     Hope the picture load.

[Bugflipper]

http://riflegear.com/showproduct.aspx?ProductID=214&SEName=stag-arms-compensator-68mm
There were quite a few on google  1/2x36 compensator as a search. A lot of them were $60-90 just put a cheap one up.

[Booyah]

Thanks Bug,
but the one you showed me want work either.  It has the correct thread but it is for a 6.8 bullet which is smaller than the 7.62   so I cant use it.   And all the other Compensators that I found with the correct thread or either to small caliber or to large of caliber.  It seems that the 1/2x36 is standard for 9mm  which has to much clearance over the 7.62 bullet.  Everyone that is for the 7.62 seems to have a 5/8 thread which I could put on a adapter but I would rather have it lockup on the barrel for a better fit.   

[Bugflipper]

Couldn't you enlarge the hole to the size they told you? Looks like it would already be centered perfectly for a pilot hole, worse case you could take it to a machinist. But most likely could find a bit  to ream it to the proper tolerance.

BTW how effective are these? I would be interested in swapping out some flash hiders if they work well for recoil and muzzle rise.
Thanks

[Booyah]

Yes you probably could open the hole size up, unless they have hardend the part, and it would be rather easy to do.  Specialy being the worst case have a machinest do it.   And it is helpful since I am a machinest and I own a machine shop.   

From reveiws that I have read, most of the Compensators that only have the Vertical slots ( Like the Stag Arms) and ones that are made with the big holes or cut outs only on the sides dont work as well as one made with ports on the top.   Thats from reviews I have read, not from actual experience.  I have a one rifle that has a factory Compensator and it has holes completly around the barrel and it works great. It is on a 7STW and the recoil is tamed down to about what a 243 would be but is extremely loud.   I have a 44 Mag pistol that is Magna Ported and the way it is made , there are 4 very small slots cut on the top of the barrel, none on the sides. The 44 Mag is comparable to a 357, so it helps some.    Looking at the target that I posted, that 5 shot group was made at 100 yards with me pulling the trigger as fast as I could holding the crosshair on the center.   The muzzle didnt rise any and recoil from the 7.62x39 was next to nothing.

[Bugflipper]

I apologize Booyah, it's hard to read on those little phones. You already made a nice one. Good job. I am going to have to read up on them a bit.
I really want one for an hk91. I shoot it prone and it can be a little slow to get back on target.
Thanks

[gunnut69]

First let's get this out right from the start, I hate compensators... but they do work. They simply redirect the energy of the muzzle flash in a direction so that it's 'jet effect' can soak up some of the recoil energy... The more gas at the muzzle and the higher the muzzle pressure is the better they work.. So a .40 S&W will work beter with a brake the a .45 acp. A 7mmSTW would be a great candidate as this is a huge case and burns large amouts of powder at rifle velocities which results in a high muzzle pressure(slow burning powders don't you know...).  And I suppose that's also the rub as they say.. All that redirected gas creates a tremendous pressure wave front.. that is, a very loud moise.. That is to say, the louder they are the better thay work.. They work but hearing protection is a must.. I would rather a 'lead sled' at the range and no brake..  P.S. Pitol brakes such as the MagnaPort seem to work as wel as they do by redirecting the gas up thus limiting the violent muzzle rise common to heavy pistol calibers..using less gas but restricting the direction(s) it is directed..