Muzzle Brake is canted/not straight

[Bossman-x]

I have an M&P 15 5.56 AR and removed the stock flash hider. I replaced it with a muzzle brake and timed it using a crush washer. It's perfectly lined up, but when look from the sides, it looks like it points downward ever so slightly. I'm pretty Anal and everything looks wrong to me, but I had a few people look at it and say that it does cant downward. I have a few questions:

1. Is there "some" play for a muzzle brake (y comp bushmaster 3 hole... not the mini it's about 3.25" long I think)? I can easily pass a cleaning rod through smoothly and see light through and through (I know not te most scientific). I had a few people say it must be perfect and some people say that you won't notice a difference in accuracy. I'm afraid the bullet will "glance" off the top of the muzzle and cause inaccuracy. Obviously won't know until I try, but I'm afraid of any safety issues.

2. Is there anything I can do other than having a gunsmith look at it to ensure that its at least safe to shoot. I can see if its accurate at the range.

3. if its cant'd a bit even when the crush washer isn't on, does that mean my threads on my barrel are bad or my muzzle brake threads are off? Should I care if its a little off.

I know its hard to give an answer without looking at it, but any advice on what techniques or cool things I can try to verify/test for at least safety.

 

[Thedub88]

I held up a straight edge up to your pic and it looked ok to me. Try it your self and see

 

[Floppy_D]

Backlight the bore, scoot back a bit and look at it again, shouldn't be too hard to see. If you threaded it on and didn't sense any wobble, should be fine. I'd be more suspect of that UTG rail being bent up.

 

[Waywatcher]

Yep, try using some straight edges. Compare the brake to the barrel.

They're cheap if you don't have 'em.

 

[Bossman-x]

Yeah, the UTG thing was all I could afford this time. The straight edge thingy (dumb question, but..) As the Muzzle Brake is larger in diameter than the barrel, I assume all I would do is lay it on top of the brake and have the length of it run over the top of the barrel and see if the gap is EQUAL from one end to the other? If there is a slight difference, what amount of difference should I care about regarding safety. I just want to shoot the damn thing and just see, but I also don't want to cause any damage to it or myself. What do you guys think?

 

[rcmodel]

If a well fitted cleaning rod in the bore passes through the hole without touching, it is straight.

Shoot it.

At the worst, accuracy will suffer if it's off a little but not enough to measure or see with the cleaning rod.

rc

 

[Bossman-x]

Yeah, the cleaning rod I have is a 1 piece long bore rod and it goes through fine, but how do you determine it its touching? Any special techniques or ends you recommend? I was thinking of getting a laser "bullet" bore sight and chamber it and see if the light come out without glare but I don't need one and had to spend the $25 bucks for something I don't use anyway.

 

[Chawbaccer]

If it really were bored crooked, you could unscrew it half a turn and it should be pointing down then.

 

[rcmodel]

Just shoot it.

After a few shoots any bullet contact will be marked with a brass streak on one side inside the hole.

Then look at the muzzle end and see if the powder fouling is consistently the same all the way around the hole.
If it is, you're good.

rc

 

[Bossman-x]

yeah, that sounds like what I'll do. I suspect it will hit the top of the brake on the way out, but if I can sight in with good accuracy at 50-100 yards then I'll be happy with it. I'm just the kind a person who will be constantly bothered by something I know is slightly off, even if there are no real measurable affects.

 

[rcmodel]

if I can sight in with good accuracy at 50-100 yards

If the bullets are actually hitting the hole in the comp, you will get NO Accuracy.
That would start them tumbling and 50-100 yard accuracy would probably be off the paper.

If the bullet is not hitting the hole, but just coming somewhat closer on one side then another?
It may shoot O.K., but I would not expect bench-rest quality groups as it will probably induce a slight bullet wobble that will take some distance to stabilize again.

rc

 

[Bossman-x]

Ok, I took it to the range and sighted in at 25 yards. before I put the muzzle brake on, I had it sighted at 25 yards with 1" groups. With the brake on, I had to adjust quite a bit to my eotech, I was hitting low about 7 inches with the brake. I was worried because that close being almost off the paper by just putting the brake on makes me think that it was hitting the brake as I suspected, but I see NO brass wear or unusual marks on the brake. I flashed a light on all sides and see nothing indicating it hitting the brake on the way out. Is this normal to zero in at 25 yards then be off my 7 inches by changing the brake OR do you think I still might be grazing the top of my brake. here is the big question. If my groups are all within 1 inch of each other does that say anything about my concerns of my canted brake or does 1 inch groups at 25 yards pretty much say that my brake is perfectly fine. One other thing worth mentioning is that maybe my big adjustment was the fact that I took my eotech off and put it back on... albeit perhaps a 1 T-Rail off.. couldn't remember. Anyway, anyone that can shed light on this would be great. I'm a newbie to AR's, but I can't get enough of them now.

 

[rcmodel]

If you took the EO off and put it back on in the same slot, it could & will most certainly change your zero a little.
Even moreso if you put it in a different slot.

The comp doing what comps are supposed to do = prevent recoil driving the rifle up before the bullet gets out of the barrel could also account for it shooting lower.

I don't think you have a problem.

rc

 

[Waywatcher]

7" at 25 yards is pretty darn extreme change in POI.

Lay a long straight edge on the muzzle brake while installed.
Lay another second straight edge on the barrel.

Are the straight edges parallel?

The straight edges will allow you to extend the line and will make any difference show up.

rcmodel is probably correct, but I would still throw some straight edges on there for some peace-of-mind, myself.

 

[Bossman-x]

Ok, I did the straight edge thing and they are slightly off. The question, is it off enough to cause any impact on accuracy? The only thing I can say is that at 25 yards (which is all I have access to at the moment), I shot about 300 rounds and I can get all rounds within 1 inch on the bench. Would that constitute no bearing on accuracy with the slight cant of the muzzle brake. It's definately not hitting the brake, but was wondering if it wasn't completely straight that it would cause inaccuracy from muzzle blast. 1 inch groups from 25 yards is fine with me, but wonder if at 100 yards that will turn into 3 or 4 inch groups on the bench. I could swear that before I put the brake on I was hitting multiple shots in the same hole and 1/2 inch groups at 25, but maybe I was lucky that day. What do you think?

 

[Waywatcher]

Try reinstalling the original flash suppressor and see if it is canted.

If it is not, then the muzzle brake is wonky and should be replaced.

 

[Zak Smith]

Could be the shoulder on the barrel, threads, or the crush washer.