Live and Learn, muzzlebrakes...

A

alinwa

oft dis'd member
Well, I just learned something, don't make an "expansion chamber" in a muzzlebrake without you port it.

LOL :)

I spent all afternoon yesterday making an adapter so that I could screw my 5/8-32tpi brakes to a 5/8-28tpi muzzle thread. The resultant adapter had an open "chamber" or 5/8 diameter section about 3/8 long right in front of the muzzle before entering the brake.

The entire apparatus is now somewhere downrange of my bench, NOT in the first 50yds....and the rifle ripped out the back restraint on the sled and launched clear. I caught it before it hit the ground.

Ohh well, as they say on my real job, "if you ain't screwing up you ain't trying hard enough"

Back to the old drawing board

al
 
Do you think it just 'grabbed' more air than the threads could handle...?
 
Al

You do understand that a brake also needs a hole in the end? Preferrably, one bigger than the bullet.

;) ;)
 
Nope, it took in 50,000 psi and couldn't bleed it fast enough thru the little exit hole. It blew up like a friggin' balloon.

al
 
If you are just testing, I would imagine that a radical increase in the adapter's diameter might get you by. I am glad that you weren't hurt. what was the OD?
 
Boyd,

about .750 but threaded on the outside too (I made a multi-purpose adapter) so less than a tenth inch thick and part of it was un-contained. My guess is that it swelled enough that the threads just slipped over, the threaded portion of the barrel was undamaged. These muzzle brakes take SUCH a smack on big guns!

al
 
WOW....... I would say you`re a lucky man.....Thank God......
HHHHhhhmmmmm...... reminds me of the time I made one outa delrin ( for weight ).....first shot.... my buddy ran out 35 yds. and brought it back to me..... 2 pieces....
I make mine patterned off a Vais.....they work good.... if you`re careful......I load 20 rnds. for b-4 and after testing......have`nt had one deter accuaracy yet.... but won`t be surprised when I do....
bill larson
 
alinwa said:
Nope, it took in 50,000 psi and couldn't bleed it fast enough thru the little exit hole. It blew up like a friggin' balloon.

al
Click to expand...

Unless your rifle barrel is 6" long the pressure at the end of the barrel was not 50 000 psi, more like 3000 - 5000 psi. Just make one without an expansion chamber.
 
PEI Rob said:
Unless your rifle barrel is 6" long the pressure at the end of the barrel was not 50 000 psi, more like 3000 - 5000 psi. Just make one without an expansion chamber.
Click to expand...


OK ;) not 50,000psi but I'm going to say it's still over 15,000 since this is a 338 pushing a 300 with 100 grains of powder. From a 26" barrel.

Yeahh there's no problem with properly designed brakes. I've used 7 different designs on this platform alone, I just got a little too wonky with this setup trying to do too much at once. Heck, muzzle flip could have contributed, I had a lock-ring, 1.4" of threads, the adapter collar, another adapter collar and then the brake screwed onto that. Talk about a Reuben Goldbergian setup...... I'll just have to bite the bullet and re-thread my muzzles each time. "Problem" is that I've got a box of brakes from various mfgrs, 6 different threads, and I test the various brakes head to head on three platforms. A 308, a 7MM Mag and a big 338. I've got a perty good hannle on brake effectiveness at this point, this was one of my last "confirmation" tests before switching everything over to Harrell brakes. (OOOps, I just said a good thing about a product, by NAME....)

There were no safety issues. I bungee the rifle down to the sled, stand behind it with safety glasses on and pull a rope to fire it. Even if it blew up I'm 6ft away. But this wasn't a "blowup event." Not even the first muzzle brake I've blown downrange.

!!

:)

al
 
Quickload will tell you what the pressue is at the muzzle.

Build your own brakes and get what you want.


Brakes below work great. No sled involved. Bored out internally for an expansion chamber. The expansion area aids in directing gasses out the holes, reduction in recoil compared to a brake with no expansion chamber.

Brake on a 338 Lapua. 308 on the right

ry%3D400


Brake on a 408 Cheyenne . Used in prone position, no holes on bottom.

ry%3D400
 
Last edited by a moderator:
Problem is.... I'm making these brakes "tunable," screw adjustable to function like an overhang "muzzle device."

al
 
alinwa said:
OK ;)

Yeahh there's no problem with properly designed brakes. I've used 7 different designs on this platform alone, I just got a little too wonky with this setup trying to do too much at once. Heck, muzzle flip could have contributed, I had a lock-ring, 1.4" of threads, the adapter collar, another adapter collar and then the brake screwed onto that. Talk about a Reuben Goldbergian setup...... I'll just have to bite the bullet and re-thread my muzzles each time. "Problem" is that I've got a box of brakes from various mfgrs, 6 different threads, and I test the various brakes head to head on three platforms. A 308, a 7MM Mag and a big 338. I've got a perty good hannle on brake effectiveness at this point, this was one of my last "confirmation" tests before switching everything over to Harrell brakes. (OOOps, I just said a good thing about a product, by NAME....)

al
Click to expand...

How do you find time to work and still play this hard...?
 
It's been winter, I can only pour concrete in the daylight. And I can shoot 24-7 since the range is 0 minutes away :)

al
 
Al, would you mind posting the pros and cons of some of these brakes and why you chose to use one brand?

Quickload will tell you what the pressue is at the muzzle.
Click to expand...
Well now I'm curious, can anyone here do this and post it?

Cheers
 
Hi alinwa. I am trying to make a brake with a tuner for my 6-284 for long range Praire Dogging. Any way you could do a photo or rough drawing so I don't have the same problem. This will be my first lathe project. Don't need any excitement!!! Thanks, Don
 
OK, alinwa muzzle brake theory 101.....

Rule #1- "A muzzle brake is a sheet of plywood held up in the wind."

Rule #2- "The wind is the propellant gas, AFTER THE BULLET IS GONE the leftover gas provides the wind."

Rule #3- "The more efficient a cartridge is the less excess wind it produces."

Rule #4- "The bigger the sheet of plywood the more wind it catches."


So there you have it, You stick up a sheet of plywood to catch the gun.......Of course the "sheet of plywood" is the impact area of the brake and the "wind" you use is the muzzle blast. So, for big recoil you need to put up big impact plates to catch the gun. The single most effective design is the "clamshell" design which has huge impact area but it's impractical for tuning because you have to keep it oriented correctly. Designing it for orienting it flat while making small adjustments makes for a lot of moving parts and it takes such a huge hit from the gases that it's hard to keep it from shooting loose even when you wrench tighten it.

Also effective are designs like the Benny Cooley http://www.brownells.com/.aspx/pid=27074/Product/AR-15-M16-BENNIE-COOLEY-TACTICAL-COMPENSATOR or the Holland Quick Discharge and Radial http://www.brownells.com/.aspx/pid=6905/Product/QUICK-DISCHARGE-BRAKE as well as a whole slew of custom jobbies. You need two things, big impact plates and big enough holes to get the used gas out of the way. A BIG clamshell like this http://www.micordefense.com/ will stop a truck. (The clamshell is in the top pic, NOT the little thingies being advertised on the page.)

Generally speaking ALL of the big wide side-discharge brakes are non-tunable IMO except for liddle guns which don't really need them anyway. I can make a tunable side-discharge setup for even say a 300WSM, it's cool for spotting shots, but step it up to the 338 and above and the forces are just too great to be practical.

IMO :)

And they're BIG.

So I figgered out the impact area of the big Harrell.

Hokey Smokes Bullwinkle! It's bigger! It doesn't bleed off quite as well but with some small modifications.......

Anyway, I've got it working just as effectively as the side-discharge brakes of equal size. And with no modifications a'tall you'd be hard pressed to feel a difference on your shoulder.

Nope, it's not as effective as the big clamshells but it rivals the Holland and Benny Cooley styles for size and it's within 10% of the 1.75" wide by 1" tall clamshell. And to make it tunable you just screw a collar on behind it. Downside is that you have to fit a plate to the bottom to eliminate down-blast and convert it to down-force, BUT I can do this without compromising the integrity of the threaded joints.

So, in short, cylindrical muzzle brakes are dead easy. If you can do basic machining you can fit a brake in minutes. You can also make your own brakes although making one as good, and as cheap as Harrell's sells them is impossible for the backyard machinist. (Also, the Harrell's make them RIGHT, they absolutely maximize the impact area.... Only a select few of the other round ones are as effective.) Side discharge brakes are also fairly easy altho timing them while getting them TIGHT is a little hard and getting them to tune kinda' sucks.

Installed conventionally and correctly you will NEVER blow one off.

I blow them off because I'm an idiot, I run the ragged edge while testing. I also believe that you can't really be a GOOD truck driver until you've rolled a truck or two....

Well, I gotta' go. I've got concrete to pour in the morning.....


opinionsby





al
 
al
I think its great that you have big enough shoulders to admit a set back. With out set back, or failure you cant ever possibly succeed to the fullest potential. There are a couple guys that lurk around here who would never admit to such a mishap. There pride is bigger than there ass!!! Now you know what needs to be done, and i really believe your on to something with that tunable muzzle brake. Matter of fact that very topic has been on my mind most of the week. I may ask to give you a phone call this weekend if your not to busy. Havent talked with you in a while anyway. Lee
 
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