Specialty Pistols
Muzzle brake to barrel

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June 29, 2016, 02:44 PM
johned
Muzzle brake to barrel
I have a Benchmark Bull with one of their brakes mounted. They did it when the barrel was made. Excellent performer, by the way. My issue is that this brake is threaded "TIGHT" and holds the index perfectly. It is the only brake I have owned that does so and I am installing three brakes soon and Benchmark isn't involved. I want to turn down the barrels to fit my new brakes "TIGHT" like my Benchmark items. The thread dimension on my new brakes is 14 X 1. What dimension should the end of the barrel be that I will cut the threads into? All the barrels I have looked at have comparatively loose fitting brakes that will need to be fixed and indexed somehow.

Looking for a measurement something like 14.1 or 14.02 or what will work. Better would be the dimension of the brakes I have "plus 5%" or some such.
June 29, 2016, 05:42 PM
rickiesrevenge
Can you post a picture of the brake they did for you? I'm having a hard time understanding how the threads are holding the brake in its indexed position.

Aaron
June 30, 2016, 01:15 PM
40xmike
Holding the pitch diameter close, not the thread major will determine the "tightness" of the thread. Who is building brakes with metric threads?

-Mike
July 01, 2016, 12:42 AM
johned
Rickie,

Go to Benchmark Brakes and mine is the last one on their list and is named tactical round- large. Has 4 holes in the sides. Not apparent is that the holes are oriented/biased to the top. That gives the brake some muzzle "flip" suppression as well as recoil suppression.

The indexing and locking is achieved by their having made the threaded hole in the brake under-size so it squeezes the threaded barrel. OR the barrel was threaded oversize to get the same interference fit. It is very tight and difficult to turn. Like it has lock-tite on it but it doesn't. Easy to do when you are making the brake or barrel. I have the brakes and I know their dimension but I need to know what size to make the barrels in terms of the brake attachment point diameter.
July 01, 2016, 01:19 AM
johned
40,

Please excuse my ignorance. I don't know what pitch major and that other thing are.

I have a CZ 58 Assault Rifle in 7.62 X 39. It is metric. On it I installed a CNC Warrior muzzle brake and flip suppressor model SLOVAK BRAKE. It is standard issue with the gun for the Czechoslovakian army. Or was. It is the absolute best brake and suppressor I have ever fired and two Smiths agree and friends. There is absolutely no flip and if I load one round so the bolt holds open there seems to be absolutely no vertical movement of the muzzle. The AK round has very little recoil in the CZ 58 anyway and with this brake there is only a tiny bit. An all round winner combination. And the prize is that the thing comes finished in black and is hardened and costs......$30. I have a 7/barrel coming for my Striker in AK and I want to fit this brake to that barrel. I also want to try the brake on my 6BR and my 308. CNC Warrior sells thread adapters to change the 14 mm to in sizes common for domestic brakes.

I will refinish the outlet of the brake to match the 6mm.

Given that this brake has flip suppression it also must be properly indexed. And that index must be lockable. What I have been doing is shortening the brake threaded portion to get the threads to bottom out at proper index. I can still do that but I wanted to do it like Benchmark, if possible.

That CNC Warrior brake can be ordered in a lot of different thread pitches and sizes. For 30 dollars you might want to give it a try. The AK uses 14 X 1 LH and the CZ uses 14 X 1 RH.

CNC is USA made and top quality.

John
July 02, 2016, 04:16 PM
LoneStar
CNC's site does not list a "Slovak" brake.


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“The 30-06 is the world's most over-rated big game cartridge" - Elmer Keith
July 02, 2016, 05:54 PM
rickiesrevenge
How are you threading the barrels for the brakes you're putting on?
July 03, 2016, 02:21 AM
johned
Lone Star,

That brake was designed by CZ for their model 58 assault rifle. On that gun and using common Wolf 7.62 X 39 AK-47 ammo the performance is unbelievable. With a single cart in the mag the 58 will "hold open on last shot" unlike the AK. If the bolt is restrained, as it is in hold open then the gun has zero flip and very little recoil. They did a outstanding job. They, CZ, call it the Slovak Brake and they equip their domestic army rifles with it instead of a flash suppressor.

Everybody that carries that brake calls it The Slovak Brake. Maybe a copyright issue has come up but doubt it. On the CZ site they sell for $45 and on all the accessories sites it goes for $35 to $70 and they are identical and most are made by CNC Warrior. CNC is a superb manufacturer of a lot of stuff and it all has good reports.

I have threaded a 243 and a 308 and a 7.62 X 39 for my Striker. I will eval the brake on all of them. As cheap as it is i can afford to modify the brakes for the each caliber. Looks to be a fun project and lots of brakes are spendy.
July 03, 2016, 02:27 AM
johned
Rickie,

I have a bore centering guide for the die. both I ordered on line for small change. Today I threaded two barrels for the first time on a lathe. Had a ton of material to remove from a full bull but still didn't take a discouraging amt of time. For one barrel I didn't have a bore guide for that cal so we used the lathe to hold the sie and manually turned the lathe to thread the muzzle. The mic says it is perfectly centered and the mounted brake is true to the bore axis. Gun is out being Smithed so I won't get to eval them(barrels) for a couple weeks at least.
July 03, 2016, 02:39 AM
johned
Answering my own question:

The threaded muzzle on my CZ 58's is .539 inches. That fits the CNC brake loosely. To get the brake firmly fixed I have to run it up onto the front site and tight. i index the brake by sanding a small amt from the rear of the brake till it is indexed when the brake is tight against the site.

The brake that Benchmark instaled on my 6mm bull is indexed but it stays put because the threads are very tight and a wrench is needed to rotate the brake.

I cut my new barrels to .543 or 4 thousandths larger than the OEM barrels. It was difficult to initially start the die but maybe it was as difficult as it should be. What I do know is that the brakes fit tighter than any OEM and I like that. They are not quite tight enough to let them sit for anything but evals. i will sand them and index them proper. i will take some film of their performance at the range. Need a month or so to do it and learn the process. At least.
July 03, 2016, 09:18 AM
Hoggin
all of us would cut the threads with a lathe....die nuts are for repairing threads bonk
July 05, 2016, 02:07 PM
johned
Hoggin,

And "all of us" would be correct in doing so. Problem is I have access to three lathes and none of them will do METRIC. Everybody around here that has a metric capable lathe that I know wanted $100 to cut the barrels and mount the brake. I dearly wish I had that metric lathe as I could have made an equal fit to Benchmark and indexed the brake with a wrench. But that would have cost me $390 to brake three barrels and I now have only the cost of the brakes invested as the Smith and I traded some labor. The MOST important thing is that I got to have my nose fully engaged in the operations and totally enjoyed my hour in the shop as a hands-on spectator.

Not sure I am in full agreement that a die is "only" for chasing threads. I own thread chasers and they are not dies. Now if you are speaking about Smiths then "probably" as they are known to me to be rather anal, as they should be in this racket with our consequences, and run things at the outer limit of quality.

But your comment is well made and timed as any clarification or alternative in this arena is welcomed by me. Thank you.

John
July 05, 2016, 02:27 PM
johned
Here they call it the "Knurled Compensator" and it is on page one.

Not clear from the pic is that there is a large hole at the end of the compensater for recoil suppression and two rows of three smaller holes in the top for flip suppression. Top holes are run at 10 and 2 o'clock posits for flash avoidance.

Among brake discussions there is a term that means that the brake has a series of "chambers" internal that have a relief recoil hole associated with them. Much more difficult to machine, I imagine. The Slovak has a single chamber inside with the 8 holes drilled into it and the bullet bore hole for 9. I guess they got the locations right based on results.

John
July 10, 2016, 10:38 AM
bowhntr/convert
Hey johned Im sure you dont know but the guy you just talked to named Hoggin is one of the best along with some other folks on here that are very highly rated gunsmiths that deal almost in pistols only ! Very good at muzzle brakes so check out his web site before you make like he doesnt know what hes talking about !!! thumbup
July 10, 2016, 12:23 PM
MClark
Could you drill out the metric threads in the brake and rethread to "standard"?
As I am sure you know the threads must be cut very straight to not get bullet strikes, cutting threads with a die this can be an issue.

Mark
August 21, 2016, 06:28 PM
johned
BOW, Re-read my posts. I thanked him for his comments and his post clearly said he is a Gunsmith. I am not confused about my being a rank amateur compared to Hog or most others but my humility is for my confession alone. I know this is a "flat" medium but I believe I have been clearly humble and not talked down to any Smiths or anyone else.

All of my barrels that have brakes installed have factory installed muz threads. I don't think I am too far out on a limb to assume that these threads are machine cut, as Hog says the/any Gunsmith would insist on doing. The brakes are made by CNC Warrior, a truly professional manufacturer. The brakes wobble badly till they bottom out on the front sight that is mounted to the barrel just short of the muzzle end. The manufacturer has installed a locking pin to insure the correct timing of any brake/flash hider or whatever. If that locking pin is utilized to time.orient that brake the brake rattles a bit. I am trying to defeat this interplay6 as I am convinced that anything rattling around on a barrel detracts from accuracy. Assault rifles are a 4 MOA accurate firearm and with that expectation I guess a lot of corners can be cut but I am looking for better performance because I can.

Nice to talk to all of you and I am certainly benefiting. Thanks.

John
August 21, 2016, 06:37 PM
johned
M Clark,

Yes I am aware that bullet strikes against the brake are DANGEROUS. And the closer the bullet fits the hole in the front of the brake the better that brake can be made to work. There must be vocabulary words for all that.

I have many guns that have that 14 X 1 threading. Part of the beauty of this brake is the rock bottom price. The other is that the thing performs so very well on the 7.62 X 39 round. The last advantage is that CNC has "hardened" the piece to match the CZ guns that are intended to receive it so drilling and cutting new threads is more a chore.

Your cautions was well made and the questions were certainly logical and I thank you for all that.