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Discussion Starter · #1 ·
I have an AK74 style muzzlebreak from bushmaster installed. It has two set screws on the bottom and a pin that goes through the front sight.

I took my mini out shooting today and I noticed the pin is starting the shear off. I double and triple checked to see if there is any interference, and I couldn't see any.

This has happened to me before and I mistakenly thought it was a faulty pin. In fact my sight is scratched on the bottom from the set screws.

Anyone have any ideas? I have only put 30 rounds through it with this pin. I'm kinda sketched out about this and I am hoping it is an easy fix.....
 

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Discussion Starter · #3 ·
Hi Bushwack,

I thought that might be the problem, BUT after close inspection, I really don't think so. I looked for any evidence of wear or scratches and I can find none. Also, I have the same POI with or with out the break on. If the bullet was hitting, wouldn't my POI be all screwed up?

It's too bad this is happening. That break REALLY works great at reducing muzzle climb....hmmm....

I'm going to give bushmaster a call tomorrow...
 

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Bubba,

It seems like there would be lead/copper residue on the rear facing surfaces of the brake if the bullet was shaving an edge. Probably on one side.

Alotta whoopin' and hollerin' down the firing line would be another indication. :D

How's accuracy with the new brake? Gettin' a few fliers? A close fitting rod down the muzzle should show if there's a gross misalignment of the brake.

Yote
 

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Discussion Starter · #5 ·
Hi Yote,

I haven't really had a chance to check for accuracy yet. This is the second time I've taken it out since the winter (and bedding the stock, adding a buffer, etc.). From what I've seen so far though, the accuracy looks very promising. I was able to hit a soup can from a free standing position at about 80 yards :)

As far as the cleaning rod is concerned, I never noticed any binding. It seems as though the brake clears just fine. That's why this is puzzling me. Could the pin be too weak?
 

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bubba---Is this pin a roll/spring pin or is it just a solid pin that holds your sight on? I ask because a roll pin is just tough as hell & will take a great deal of abuse. I can't imagine anyway a muzzle brake could damage one outside of using the thing as a pry bar & even that would surprise me.

Good luck
Bushwack
 

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Discussion Starter · #7 ·
Hi Bushwack,

I think it's a roll pin. It's not like the stock one that comes with the mini, though. In a section view, it looks like a "c". Maybe today I'll post some pictures.
 

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If it's not the bullet hitting the brake, then it's the gasses hitting the "deflector" surface. I would not be surprised if forces the brake experiences resembles hitting it with a hammer. Those gassess come out of the barrel all of a sudden and pack quite a punch. The recoil-reduction action must be great in that type of a brake. I had it on my AK-74 in the army and it was shooting so sweet compared to AK-47, but since I never had a chance to shoot without it, I can't really compare.

I would recommend attaching the brake as good as possible and leaving it there. How about using a better pin and drilling identations in the sight sleeve for the bottom set screws to act as pins?

Alternatively, you can probably increase the diameter of the hole just a bit, which will reduce the efficiency of the brake somewhat as well as the forces acting on the brake.

V.
 

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I would think if the bullet was hitting the brake it would cause the bullet to keyhole. Shoot at some paper targets to check it out.
 

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Discussion Starter · #11 ·
Thanks for the info guys :)

I just got off the phone with Bushmaster and they are sending me some more pins. I double-checked the brake and the bullet is NOT touching. I did put my cleaning rod through the barrel to check clearances from the brake and everthing is OK.

I am going to take some of your advice, Voruzon. I don't have access to alot of the tools needed, but I am going to try to indent the sleeve where the set screws are. I didn't torque them down that hard before. I am going tighten them more this time and use red locktite. I also might try a small bit of epoxy.

As far as the performance of the AK74 brake is concerned, it is excellent. I was amazed on how much it reduced recoil and muzzle climb. Actually, the muzzle does not rise at all. I just feel a gentle push directly backwards:)
 

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Hey bubba, someone else in this forum had the same problem with that brake. The fix was to drill start the sight where the set screws are susposed to seat. Then they loctited the screws threads, they didn't have anymore problems.


Welcome to the forum Yote. You gave the same advice I would have about using a cleaning rod to check for clearence. Thanks
 

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bubba052698: As far as the performance of the AK74 brake is concerned, it is excellent. I was amazed on how much it reduced recoil and muzzle climb. Actually, the muzzle does not rise at all. I just feel a gentle push directly backwards:)

I know it is, I just never had a chance to see how ot shoots without the brake. I should have tried when I had a chance.

It's is even better it in full auto. The 5.45x39 bullet is rather weak since it does not fragment, but with AK-74 in full-auto one can put 3 rounds in a head-sized target at 30 yards to compensate for low lethality.

With AK-47 if I tried to shot 6 rounds full-auto, the last one would go into zenith. :)
I am not a heavy guy.

Please, post the info on that muzzle brake when you work it out. I am seriously considering discarding the JM brake and getting one like yours - or affixing a lead weight ontho the end of the barrel.
I have nothing against JM brake (that I got for $13.39) as a quick barrel-end weight and possibly flip reducer, but it is not a brake by any stretch of imagination. Not that a Mini really needs one.

V.
 

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Voruzon, a muzzle brake does reduce recoil, but it also reduces bullet velocity some. I have seen figures of aprox 4%. If you are a frag guy, you need the velocity to fragment your FMJ. The bullet will still frag, but the range may be reduced a little. Just something to think about.
 

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Discussion Starter · #15 ·
Voruzon,

When I get the break back on and throw some rounds, I'll fill you in. I was able to shoot my gun without the break a day before I shot it with the break on. I know the mini doesn't kick a whole hell of a lot, but the different was drastic.

Since the break is so effective, maybe that's why I sheared the pin. A tech at bushmaster said the force created by the gases on the break is quite large, kinda like hitting it with a hammer.
 

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Discussion Starter · #16 ·
oh, and on a note about lethality......

My friend has a calico m900 9mm assault rifle with a 100 round clip. Even though it is semi, I can easily pop off 5 rounds a second with virtually no kick or muzzle climb. My friend's opinion on the 9mm is "it maybe weak compared to a 308, but I can put 10 rounds in a 6 inch circle at 50 yards before you can say "holy sh-t!!" :)
 
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