AR Sponsor
Posted: 7/7/2005 10:39:29 PM EDT
| im going to college in a manufacturing program and i just got the go ahead to make my own muzzle break. I cant bring in the barrel because of campus rules and im not going to pay a gunsmith to thread it. What does the diameter of the hole the bullet passes through supposed to be? .223" ? Bigger than .223? I am thinking of making it in a style very similar to the Y-COMP. |
|
In this link to Brownells, they describe the Ops Inc four port brake in some detail and state that the bore of the brake is 0.030" larger than the bullet diameter. Link |
|
thanks for link. now is there a way to thread barrel without a lathe? In the shop and in my textbooks ive seen tools that look like a thread tap but external rather an internal... Or what ive i thread the muzzle brake to fit on the non threaded barrel and just screwed it on there nice and tight? |
Unless your barrel muzzle is already at 0.498", for 1/2"X28TPI, you need a lathe to turn it down to that diameter, then you can use a thread guide in the bore to squarely start your threading die. |
If that's your present barrel OD and your required threads major diameter, thread away.  You might end up with an "odd" looking muzzle brake, but aren't they all "odd" looking anyway???? 
|
I wouldn't trust a threading die to start straight enough without a guide like Mongo described. You won't be able to find a SAE or metric thread that is .698-.700 (17.72mm) on the major diameter. I'd just machine the bore where it slides over the barrel .001 to .002 less than muzzle diameter, heat it up and press it on. You won't need to worry about indexing your ports either if you press it on. If you do manage to thread it you can put your crush/peel washer in front of the muzzle where the barrel butts up against the inside of the brake. Your brake design will work, you don't need holes on top. Machine the brake .002 less than the barrel, throw the barrel in the freezer, heat up the brake and press it on  .
|
I would guess if it is not mechanically held on by pins, thread, etc., it will eventually shoot off. Hell, even the pinned on Colt brakes were shooting themselves off due to poor quality pins being used on the brakes. |
I doubt it would go downrange but if you were really worried you could pin it so that the pin just catches the barrel similar to a front sight base. If you machine it to a .002 press fit it should stay put. If you throw the barrel in the freezer for a few hours or pack it in dry ice and heat the brake for 5 minutes with a propane torch it should be able to be driven on with a hard plastic or leather mallet. Better yet use a big plastic dead blow. Once the temperatures equalize it will be solid. I'd stand the barrel straight up when pounding and slide a hardwood dowl in the upper so that the force of the beating is not placed on the upper receiver. It should really go on with little effort. It's worth a try since you would not permanantly modify your barrel. Another solution would be to silver solder it on. My solution is not perfect but given your lack of a lathe to put the barrel in it's the best I can come up with. Sometimes you have to think outside the box. |
|
I don't know about your campus' rules, but can you not dissassemble your upper and bring just the barrel in to thread? I know I could get away with that, as long as I didn't bring an actual "firearm" on campus. I could have pushed my luck and brought the entire upper, but an action block and barrel wrench run what, $40 or thereabouts? (forgot what I paid for mine) Its not too terribly hard to take one apart and put it back together again. |
I would just eyeball it. It might help to slide a 12" length of 1/2" rod through your ports in the brake to line it up 90 degrees from the front sight post. |
AR Sponsor