IMPORTANT SAFETY QUESTION - RE: Swapping Flash Hider for Muzzle Break

[TheGDog]

I put the AR's barrel in the vice. I covered the barrel with a MtnBike inner tube doubled-over.
I was leary of applying too much force with vice itself, was exerting lots of force with wrench to try to remove the BushMaster's stock A2 Flash Hider. Big problem was that it kept wanting to rotate the barrel within the fold of rubber protecting it.

Eventually to get it to grip enough to where I was *finally* able to break-free the Flash-Hider, it required that I tap the vices tightening bar with a 1# sledge just to get it a few more degrees than I would be able to do with my hands alone.

Putting on this Yankee Hill Machinery CA-compliant "Muzzle-Break"... I was experiencing the same trouble trying to get it all the way on and aligned when installed. My attempts to yank harder on the Wrench would cause the barrel to rotate inside the double-inner-tube protection.



QUESTION 1: As long as I had this problem of fighting the barrel rotating within the rubber when clamped in the vice... it *should* be impossible for me to have exerted enough pressure with the vice to have done any sort of "crushing" to happen to the bore within the barrel, correct?

QUESTION 2: Using this method, being overly cautious to make sure the barrel was mounted aligned with the vices load-bearing surfaces... there should be little chance of me being able to cause any kind of warpage to the barrel, correct?

This was my first time executing this operation, hence the reason I want to be cautious and ask others before I go and shoot the rifle to confirm everything is functional and as it should be.

 

[Aeon]

Barrel blocks are made of wood. Get a block of oak. Drill hole smaller than barrel. Cut block in half clamp barrel in vice as tight as needed.

The flash hider was probably pinned on so the threads were chewed on in removal. Worth running a die over the threads. Also a offset brake will make bullets fly funny. You might be fine or you might not be. Did you get crush washers so you can time your brake?

 

[Bowman]

I am not a gun smith. And would have to tread carefully on this one.
Barrel are are soft. Any time when trying to apply UN equal force it is bad.
It will distort a barrel. It doesn't take much. To make it go out of round.
With out doing research it's tough to make a comment.
But common sense dictates a go gauge needs to Be run through the barrel rifling. This procedure will check for size and will allow a bullet go through without interference.
have a gun smith check it
for damage is a safe bet.


It could be the flash hider was a press fit or locktite on. Depending on the grade of locktite it can be permanent.

 

[TheGDog]

It came with a replacement crush washer. Unfortunately, upon struggling with the @#$% stapled small packaging it flew open and got lost in a hard-to-get to area, so I did the sinful thing of re-using the prior crush washer. Not like I wanted to, but the plan was to take the AR out hunting this weekend for Bobcat.

Naw, the threads looked beautiful, now, in thinking about it... and remembering what I noticed on the crown, (now that you tell me they sometimes use Loctite) I remember I noticed something was on the crown. Hint of blue to it, so probably Blue Loctite, which... would explain why it was stubborn as hell. Alrighty Then! I didn't know what to make of it at the time. But I figured it was something similar to loctite. I had tried scraping it off with fingernail but it didn't wanna come off, so I figured it was something perhaps like Loctite, but perhaps more viscous.

Hrmm. Was more than likely going to take the AR for this weekend to do a set for Bobcat to try to fill this tag.

Dang it...SIGH... I guess to error on the side of caution... I'll have to take the Bolt .223 instead, until I've had time to check the AR.

GRrr... the AR has the 50mm scope on it specifically for low-light predator situation. Meh... what can you do.


P.S. Aeon.. can you expand more upon what you said about " -->time<-- the brake" ??

 

[Bowman]

The block should be bored out to fit the tapered od of the barrel.
The split in two. Wood is very forgiving. It won't damage the barrel. Plastic block could work as well. Its What i have done on similar projects
make the hole the same size or slightly smaller.
It will hold the barrel with equal pressure at the circumference.
The block most be softer than the barrel.
About the locktite. It may have been stud and bearing grade
Which is a bitch to take a part.
I use a grade that is for light
Hold to prevent coming loose from vibration. Color can be blue or red. It can damage aluminum threads taking a part. But steel
Is safe.

 

[TheGDog]

Blue vs Red - Long story shorter... Red is sorta mostly for things that are never gonna have to come back off. Red can require Heat to help remove.

Most stuff is just Blue.

I rode a KX500... Hehe... I'm very familiar with Blue Loctite.

I just would have never dreamed it would be used in an application on a firearm muzzle is all.

 

[Bowman]

Sometimes a light tap with a. No Mar mallet can break loose the threads.
Suggestion take a lead bullet and
See if it will freely pass thru the barrel with no binding. If it sticks or binds there is most likely an
Issue. A barrel is basically a shaft
With a precision hole with grooves.
Very tight tolerance. Stuff like this is verified with a go and no go gauge. Diameters are very precise.
If it goes the barrel is not under size. If the no go does not go
It is not over size.
So the bullet and the rifling
Are at a precise fit.
I may be wrong about the bullet
Pushing freely thru so it may be
A slight press. So check the specs
On bullet diameter and the barrel
Rifling.

 

[Bowman]

Blue or red can be inter changeable. It depends on the mfg or the specs.
Some grades are heat resistant
And are made to run in elevated
Temperature conditions.
There are many different applications. I have used them in
Aircraft applications.

 

[Aeon]

This got a bit sideways,

Go-no go gauges are used to check head space the distance from the bolt face to the shoulder of the cartridge. Has nothing to do with bore of a barrel.

The tool used to check a bore for deviation is a air gauge and beyond the diy at home user. Don't even know a smith that has one.

To time a brake is to set so when tight the ports face the correct way, typically to the side. The crush washer or washers allow you do just that.

Thread locker is not strange don't worry about it. I like to take mine off so anti seize is better lol

If you really think you crushed your barrel take it to a smith. Don't go shoving anything down your bore.

 

[Bowman]

Yes an air gauge can be used, I not talking about head space.
What I said is Done often to check
Precision holes.
Lead will not damage the barrel.
Air gauge is for high volume production parts.
A deltronic precision ground pin
Size to just .0005 under the minimum tolerance of the bore. It's common
For low volume. It cost about $20.
And is certified to the Bureau of standards. This a common and simple
Method.
Air gauge can cost $$$$$$.

If it passes freely thru the bore it
Good. If it does not no Bueno.
I have Inspect parts many times
This way.
A bore Gage is is used when it's
Short easy access and it's the best.
Any precision machine shop will
Have them.
The area of concern will be where
It was clamped at.
I started out as apprentice Machinist
In a gear shop, that did precision grinding holding tolerance's of .0001
In inches.

 

[TheGDog]

Welp... took a chance when I got back to my truck after hunting today.

Besides "eyes and ears", I held my AR on the other side of my rifle case to squeeze off a test round first. Then when it went thru no problem, I tested to see if it's the new muzzlebreak had thrown off accuracy.

It was night, so I just pointed a spotlight at this can (all these EFFing people that can't take their trash out with them!!! ARGH!!) at maybe 25yds and tried my best freehand to just hit it in the middle. (Which is a difficult feat when you're feet are that damn sore and you're spent and shaky!)

Not like I zoomed in or anything, it was still just set on 3x, but I'll take it! "Dem Hart Boyz are shooters! Yessir!"

 

[Bowman]

Good deal, what type of round?

 

[TheGDog]

Uh... that one was a Hornady Superformance GMX 55gr

 

[Bowman]

I was doing a little research.
And I was incorrect about the size.
For example 308 Winchester = .308 at diameter of the lands.
.300 @ the inner diameter.
.008 difference. ..004 per side.
Not including the tolerance.
Bullet diameter = .308.
Interference with the minor diameter of the bore.
That's a pretty good press.

 

[Bowman]

Uh... that one was a Hornady Superformance GMX 55gr

.223 round

 

[SteveHazard]

AR vise blocks are cheap for next time. I have one I would of sent you, it sucks, but worked.