ak muzzle device bullet impacted?

Dr Prepper · May 21, 2017

A friend wanted advice on what may be causing this. I don't think he noticed it when it happened. I know the AK's threads are fairly well known for not being concentric to bore. But is there anything else that could cause this? Trying to get a precision rod, drill blank, or reamer blank to gently slide into bore to see if the device is off centerline..
BTW what's the bore dimensions? The grooves are .311" dia. right? Or at least the bullets are .311 dia. Are the lands .308" dia. Then?
It didn't appear that the final chamber or bore hole was impacted though could this just be caused by gas errosion?
Thanks for any help.

308 · May 21, 2017

This is not unusual with a 74 style brake on a 47 rifle. The break probably did not get snugged aginst the FSB due to timing and you end up with a baffle strike.

I learned this the hard way when a friend was shooting mine and I ended up with a piece of shrapnel hitting my face as I stood rear and left of him. I got hit twice before realizing what happened.

We tossed the brake and went back to the slant brake.

Member 5605 · May 21, 2017

Clearly it's a strike and we know how it happens. There isn't much you can do beyond either reaming out the brake, ensuring that it's snugged onto the barrel and or tossing it and going with what's suggested above.

tac · May 21, 2017

AK-74 = 5.45mm diameter bullet.

AK-47 = 7.62mm diameter bullet.

Yup, that'll do it just fine...

tac

308 · May 21, 2017

The AK74 brake has 24mm threads and screws onto the FSB so there are not any alignment issues. It's the 74 'style' brakes like the one above that can be a problem since the fit sloppy in most cases.

ditchtiger · May 21, 2017

It's a pain to do but make a shim for the brake so that when it bottoms out it is clocked to the detent plunger. Involves sanding a washer down to needed thickness. Trial and error until thinned down enough. no flopping around when done correctly.