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New Mini and muzzle brake has too many holes

1K views 4 replies 5 participants last post by  cajungeo 
#1 ·
Howdy everybody. For the last couple of months I've been trying to decide if I wanted to buy a Mini 14 and my biggest concern was it's lack of accurracy. After spending considerable time reading these posts I learned that, while not a tack driver, the Mini 14 can be "persuaded" to shoot close to MOA so I bought one. I got a NIB Ranch Rifle in stainless steel with a synthetic stock (196 series) and I absolutely love it. The first thing I did was clean it really good then mount a scope and shoot for groups. I was getting 1.337" to 2.0" at fifty yards with Wal-Mart's Winchester 45 grain Varmint Value Pack.

Following the advice of the forum members I re-torgued the gas block screwsto 24 inch pounds and feeler gauged them. My groups were worse and I noticed black soot on the bottom of the barrel at the gas block. I tightened the screws a little at a time and gauged them to make sure I was keeping everything even until I no longer got the soot seepage. My groups improved to 3" or so but still not where they were.

Next I installed a John Masen Muzzle Brake which fit nicely although a little loose. A couple of shims will fix that. After a thorough cleaning my best group with the brake started out real good for the first three shots - under one inch (0.929") - but the next shot in that group went two inches to the right and the fifth and final shot hit closer to the first three shots but only about half way. Not as good as it was before I messed with it. I'm not concerned though as I still have to have it glass bedded and the trigger worked on and possibly even a cryogenic treatment.

The rifle shot better than I expected when it was new so it stands to reason it will be an excellent shooter after all the mods, I just have to get that gas block set right.

Now, about that nuzzle brake. There are two rows of three holes on top but two of the six holes are blocked by the barrel which only leaves four holes for the gas. While muzzle jump is reduced it's still there big time. Is my muzzle brake the way it's supposed to be and are the four open holes enough to do the job?

Thank's for any help you can give me and I'm sure I'll have more questions before I'm through. Hopefully some day I will be able to contribute something that will be of use to someone just as the stuff I've read from y'all has helped me.

Jim
 
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#2 ·
That Masen brake will not help muzzle jump much, no matter how many holes.

For a brake to work, the exit hole for the bullet should be just barely bigger than the diameter of the bullet, thus forcing the gases up thru holes in top.

If you don't want to mess with bedding, you can shim receiver with thin metal strips, that's what I did. Cryo will help stringing but not cold barrel accuracy, at least that's what happened for me.
 
#3 ·
Originally posted by R E TIRED@Apr 18 2005, 05:04 PM
Following the advice of the forum members I re-torgued the gas block screwsto 24 inch pounds and feeler gauged them. My groups were worse and I noticed black soot on the bottom of the barrel at the gas block.
Exact same results that I got when I first retorqued the gas block on my Mini 30. I believe that it's more important for the gas port to line up with the slide than it is to have the same side-to-side gap on the gas block. The top piece is, after all, just a clamp.

I redid mine to line up better with the slide, which meant the gap on one side is slightly narrower than on the other side. I also made sure the front-to-back gap (instead of the side-to-side gap) is the same to reduce gas weepage. After retorquing in that way, my groups are one inch at 25 yards with Cheetah ammo. I haven't shot at a paper target yet at 100 yards, but the other day at a local forest I was hitting orange clays at 75 yards and 3"-4" bits of debris at 100.
 
#4 ·
:eek: Hey R E Tired;I don't know if you are aware of the situation of "breaking in" a new mini,if you are'nt-this is the typical stuff,all of the moving parts need to "lap"themselves in to fit and create less drag/metel to metal wear.Also the barrel such as it is needs to have some of the rough spots smoothed down (in the bore)and unless you slug the barrel and hand lap with the correct abrasive compound,you can look forward to shooting somewhere between 200-500 rounds to get things to fitting and funtioning properly.Kinda like breaking in a new gasoline engine.I think that alot of people believe that it is going to shoot good within the first 2 boxes of ammo-just ain't so.These guns have too many variables and moving parts.Just be sure to use a good lubricant like teflon oil and on the barrel slide /oprod assy use some white lithium grease(sparingly).Get some spare mags and go waste ammo-more fun to break in a new mini that way! :lol: <_< :sniper:
 
#5 ·
Welcome to the forum RETired. That is normal on the John Mason double muzzle brake for the first 2 holes to be obstructed.

You are going about it correct. 1 mod at a time to see what works for you and what doesn't so you can undo any that don't.

When gapping/torqueing the gas block it is important to make sure the inner surface that mates to the barrel lays flat. Torque screws the same amount in a crisscross patern to 24-36 in-lbs.

Note the gap may not be even fwd/aft, but equal left/right.

Bedding, and a trigger job will get rid of the dissapointing fliers.
 
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