Muzzle Device Question

[Hansel&Grendel]

I built a 6.5G 11.5" Criterion barrel (NFA) and mounted a linear comp on it along with a Vortex Razor-E 1-6x. It's relatively tame but could be tamer.

I recently mounted a Precision Armaments EFAB on an 11" AR Pistol 7.62x39 that initially also had a linear comp. The recoil reduction with the EFAB is notable and the flash signature is now very nominal. To my surprise, side concussion with the EFAB is very tolerable, and actually negligible much like the linear comp. No complaints from shooters on either side at an indoor range.

On a 6.5G Criterion 16" barrel, I mounted a VG6 Precision Gamma "65" Muzzle Brake - 5/8x24, but specific to a 6.5 caliber.

Is there a disadvantage with mounting an EFAB on the 11.5" 6.5G? The thread pattern is the same (5/8x24) but it's not a "65" brake like the VG6.

Thanks, Hans.

[A5BLASTER]

No shouldn't be.

I run a m4-72 severe duty on my 20 inch howa and have put it on my pistol grendel as well.

Worked great for keeping the gun steady but my god the concussion felt like it would cause my nose to start bleeding and my eyes pop out my head.

I don't suggest the m4-72 for a pistol but the efab should work.

[grayfox]

What caliber is the Efab? if it is 308 (7.62) then there is maybe a 3% reduction in effectiveness. If it is less than 6.5 cal then of course NONONONONO!!!!!
Upsizing by a caliber or so does not affect the reduction because the gas flow through the opening is a super-super-sonic "choked" flow... so less reduction than you would figure.


always wear ear protection with any rifle shot...

[grayfox]

A5 that was my conclusion on the M4-72 also... even for a 20" it was just too much for me. kinda like a "prop wash" effect... I've settled on the VG6 65 gamma, works great, armorally had them for about 51 bucks... it's the best little brake I've found so far.

[Hansel&Grendel]

GrayFox, the Precision Armament EFAB is indeed .308/7.62 with a 5/8-24 thread pattern. If the end result is essentially the same as with the AR Pistol 7.62x39 linear comp upgrade to an EFAB, albeit with only a small reduction in effectiveness (~3%) with a 6.5G, then it will be well worth it.

Thanks, gentlemen.

[grayfox]

Ok. Now about that 3%, I was referring to muzzle benefit from the efab on a 308 rifle vs its benefit on a 6.5, this does not compare or factor in any performance by a different brake or compensator. It's not a comparison to the linear comp... in fact the reduction (on a 6.5) could be much greater than the reduction from that comp (on that 6.5).
If you look at the PRS blog tests or ttag's, then you'll see that different manufacturer's and even different device designs from the same mfr will have different reductions in recoil and/or muzzle rise. brakes tend to do a lot more for you than comp's.

[A5BLASTER]

A5 that was my conclusion on the M4-72 also... even for a 20" it was just too much for me. kinda like a "prop wash" effect... I've settled on the VG6 65 gamma, works great, armorally had them for about 51 bucks... it's the best little brake I've found so far.

Yea that's why it stays on my howa 20 inch now. I put it on the pistol just to see how good it would help control the short gun.

Worked great bit good god. Put it back on the bolt grendel.

Never really was a problem on the 20 inch ar and doesn't seem too be as bad on the howa.

The howa is a lil longer then the 20 inch ar was.

All my ar grendels just have a2 birdcage on them now and that's how I'm going to keep them.

[Hansel&Grendel]

Ok. Now about that 3%, I was referring to muzzle benefit from the efab on a 308 rifle vs its benefit on a 6.5, this does not compare or factor in any performance by a different brake or compensator. It's not a comparison to the linear comp... in fact the reduction (on a 6.5) could be much greater than the reduction from that comp (on that 6.5).
If you look at the PRS blog tests or ttag's, then you'll see that different manufacturer's and even different device designs from the same mfr will have different reductions in recoil and/or muzzle rise. brakes tend to do a lot more for you than comp's.

GrayFox, I understood what you meant by the 3% difference, i.e., between the .308 and 6.5. I worded my prior response poorly. Linear comps have their purpose, but the EFAB largely accomplishes the same thing but with less recoil and muzzle rise along with virtually no flash. Thanks again!

[pacificpt]

I have been using the KAK Blast Converter on 5.56 and 300 Black with good results. I have just put one on my 6.5 Grendel build, but I have not been able to put rounds through it yet. I anticipate the same good results with the 6.5.