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View Full Version : How hard is it to re-bore a muzzle brake?


k1dude
05-08-2011, 2:14 PM
There's a real scarcity of muzzle brake's and flash hiders available for the 6.5 Grendel. What's available is also somewhat expensive. So looking around I came across these Shrewd Muzzle Brakes for $59 at Brownell's:

http://spinstage.http.internapcdn.net/Spinstage/userdocs/products/p_860101228_1.jpg

The problem is the Shrewd's all come bored for a .22. You have to ream them to your desired bore size. I've seen people online that have found local gunsmiths to re-bore to the correct size for around $10. But I've checked around and everyone wants about $50 where I live. That basically doubles the amount of the brake and puts it right back up to the same cost as the few expensive brakes that are available.

So my question is, how hard is it to re-bore the brake myself? I'd think it wouldn't be that hard in my drill press. Am I wrong?

RugerNo1
05-08-2011, 2:24 PM
Do you have the right fixtures and dial indicator to dial in the brake so that any boring you do would be concentric with the existing bore of the brake? Without being able to bore out while being concentric all you would do is ruin the peice...

The proper way to do this would be with a metal lathe.

The Director
05-08-2011, 2:32 PM
I would think any machine shop could do this for next to nothing. $10 sounds about right. Not rocket science.

dieselpower
05-08-2011, 2:33 PM
Ok, hold up...is this made to take the sidewall pressure from a 6.8? It may turn into a 2" pipe bomb the first time its fired. The metal isn't the issue, its the way the metal was formed that does....

kendog4570
05-08-2011, 2:49 PM
I would think any machine shop could do this for next to nothing. $10 sounds about right. Not rocket science.



:popcorn:

Fjold
05-08-2011, 3:10 PM
Ok, hold up...is this made to take the sidewall pressure from a 6.8? It may turn into a 2" pipe bomb the first time its fired. The metal isn't the issue, its the way the metal was formed that does....

The 6.5 Grendel is only loaded to 50,000 PSI The 5.56 Nato is loaded to 62,000+ PSI.

dieselpower
05-08-2011, 3:40 PM
The 6.5 Grendel is only loaded to 50,000 PSI The 5.56 Nato is loaded to 62,000+ PSI.

My bad.. I read the OP as in these were for .22s not sized at .22 and had to be up-sized. Just read up on them, I get it now.

G-forceJunkie
05-08-2011, 4:21 PM
Its not rocket science, but requires accuracy. You cannot just chuck it up in a lathe jaw...the bore may not be be concentric to the outside. The threads may not be concentric to the bore. To do this right ($$$) one would indicate the brake in the lathe to be concentric with the threads. Then the bore opened up with a boring bar, not a reamer. If I was doing it, I would probably do this by chucking up a piece of bar stock, the turning and single point threading the end so the brake screwed on. Then I know without a doubt the threads on my fixture are running true with the lathe. Then I would screw the brake on, bore it to proper diameter, and square up and crown the exit of the brake. This would probably take 1-1.5 hours so $50 sounds like a fair price, if its is being done correctly. Now if you want me to do 50 brakes at the same time, its going be a whole lot cheaper because the setup and tooling cost get spread out over 50 pcs instead of one. You will never be able to do this job, accurately, in a drill press. I would think any machine shop could do this for next to nothing. $10 sounds about right. Not rocket science.

kendog4570
05-08-2011, 7:00 PM
Its not rocket science, but requires accuracy. You cannot just chuck it up in a lathe jaw...the bore may not be be concentric to the outside. The threads may not be concentric to the bore. To do this right ($$$) one would indicate the brake in the lathe to be concentric with the threads. Then the bore opened up with a boring bar, not a reamer. If I was doing it, I would probably do this by chucking up a piece of bar stock, the turning and single point threading the end so the brake screwed on. Then I know without a doubt the threads on my fixture are running true with the lathe. Then I would screw the brake on, bore it to proper diameter, and square up and crown the exit of the brake. This would probably take 1-1.5 hours so $50 sounds like a fair price, if its is being done correctly. Now if you want me to do 50 brakes at the same time, its going be a whole lot cheaper because the setup and tooling cost get spread out over 50 pcs instead of one. You will never be able to do this job, accurately, in a drill press.



At $50 per 1-1/2 hours, you are losing your a**.
To the OP, you will pay X, to get to Z. Thats why the brake from Brownells is cheaper. There are still a few steps to go. Not too many ways around it.

killshot44
05-08-2011, 7:32 PM
:popcorn:

:smilielol5:

CSACANNONEER
05-08-2011, 7:37 PM
Are the threads for 6.5 barrels and .223/5.56 barrels the same? I just thought I read something about being different for safety reasons.

hammerhands32
05-08-2011, 7:59 PM
Are the threads for 6.5 barrels and .223/5.56 barrels the same? I just thought I read something about being different for safety reasons.


The barrels from Alexander Arms have both 9/16 by 24 and 3/4 by 28, depending on the barrel. I looked around and ended up paying the $100 from AA because it was that or a custom build.
I didn't appreciate the $14.00 in shipping and handling for just a muzzle brake being shipped via standard mail.

k1dude
05-08-2011, 8:30 PM
The barrels from Alexander Arms have both 9/16 by 24 and 3/4 by 28, depending on the barrel. I looked around and ended up paying the $100 from AA because it was that or a custom build.
I didn't appreciate the $14.00 in shipping and handling for just a muzzle brake being shipped via standard mail.

That's how I felt. I was just going to get the A2 flash hider for $15 until I found out the shipping from AA was $14. So then I started my search for a 9/16"-24 flash hider or muzzle brake and found out very little was available.

It basically came down to:

1. VLTOR VC:6.5 flash hider for $52 + $8 S&H = $60

2. AR Stoner Heli-Port muzzle brake (really a flash hider) for $65 + $4 S&H = $69

3. Shrewd for $60 + $5 S&H + $50 re-bore = $115

4. WCI Muzzle Brake for $99 + $14 S&H = $113

So maybe the $29 for an A2 flash hider isn't that bad of a price considering the options. I just don't like being ripped-off by paying $14 to ship a tiny $15 flash hider.