Apparently I have been doing it all wrong. I found this on the internet while looking for something else


I just got thru doing this very thing to my 580 series. I'm a hardheaded kind of guy, like to do things myself. I measured my barrel to 16 1/4''. I then taped off the 1/2'' wide groove I wanted to turn down at this point. I took coarse grade emory cloth and cut it into 1/2''X4'' strips. I wrapped a strip around the barrel and then LIGHTLY clamped the emory cloth with a large set of curved jaw vise grips. Spin the vise grips around until the cloth starts coming apart then replace it and spin again. After about 3 hours in front of the TV you are getting close to the 1/2'' diameter you must have before threading. The barrel is 5/8'' to start with. All barrel boring is off center a little, my 580 was no exception. I had my 1/2''X28 die, handle and centering guide from Brownells. To make sure your threads are concentric with the bore of your rifle - after turning down to your threading diameter put your centering guide with the die and handle attached on to the end of the barrel. Make sure your flash suppressor is tightened onto the centering guide threads on the backside. This will enable you to turn the die down on the barrel. Turn the die until it just cuts into the end of the barrel. Now remove everything and look at the barrel. you will be able to see if it's off. Now take a nice sharp flat mill bastard or needle file and true it up, it's not as hard as it sounds. Once you get it pretty close the die and centering guide will true it up exact. Make sure you use cutting oil (50W or heavier) and rock the die clockwise and counterclockwise when cutting. This will keep your die teeth clean of debris and chips, resulting in clean threads. Degrease your new threads and cold blue. Oil the newly blued threads liberally and turn on your A2 suppressor. You are good to go. Photos of mine in ''MY NEW 580". Good Luck!!!!My A2 suppressor I notched teeth on, for fun......Big Grin

I think this could be called "a garage mechanic"

Determined guys with no tools are often very successful. Guys like that built the country.
Often, however, they wreck something; (and then they bring them to me to fix) they are best left to non mechanical devices. Like rocks. Guys like that do well on rocks. And dirt.

One of the older firms that modified AR-15's used to thread muzzles with 1/2 x 28 die for flash suppressors. They at least turned them down with a lathe. They also offered precision muzzle threading (single point threads) for suppressors. I didn't like the fact that they used dies, much less turning one down with emory paper and vice grips with no lathe! I would love to see the shoulder!

There are quite a few things guys don't understand about muzzle threading.

First off, even if both ends of the barrel are dead nuts centered, doesn't mean the bullet isn't approaching the muzzle at an angle. I have a barrel here that was center turned, but when I cut it in half, the bore was WAY, WAY, off center....at the center of the barrel. The bullets path was in one hell of a hook as it approached the muzzle. That also means the crown isn't really square with the bullet as it exits the muzzle, considering the bullets approach is at an angle.

Second, even if the muzzle threads are off center, that will simply side-shift your suppressor. It will not pitch it off at an angle. The suppressor hole is quite a bit larger than the bore, so it would have to be side shifted a PILE to cause a strike. However, if the shoulder isn't square to the bore, then the suppressor is sitting at an angle. A tiny angle problem and you're in trouble especially with a long suppressor.

Your results are going to be quite mixed when you scramble all these variables together. It's possible to have the bullet approach come in at an angle, but also have the suppressor sitting a the same angle and it works fine. Or the suppressor is sitting at the opposite angle and you're WAY off.

Oh, and that bullet twist formula you use? Well throw that BS out the window when it comes to firing through a suppressor, because the turbulence caused by the can will require more twist than the "formula" calls for.

Tony Rumore
Tromix

I'm impressed!

quote:

Originally posted by Rolland:
Apparently I have been doing it all wrong. I found this on the internet while looking for something else


I just got thru doing this very thing to my 580 series. I'm a hardheaded kind of guy, like to do things myself. I measured my barrel to 16 1/4''. I then taped off the 1/2'' wide groove I wanted to turn down at this point. I took coarse grade emory cloth and cut it into 1/2''X4'' strips. I wrapped a strip around the barrel and then LIGHTLY clamped the emory cloth with a large set of curved jaw vise grips. Spin the vise grips around until the cloth starts coming apart then replace it and spin again. After about 3 hours in front of the TV you are getting close to the 1/2'' diameter you must have before threading. The barrel is 5/8'' to start with. All barrel boring is off center a little, my 580 was no exception. I had my 1/2''X28 die, handle and centering guide from Brownells. To make sure your threads are concentric with the bore of your rifle - after turning down to your threading diameter put your centering guide with the die and handle attached on to the end of the barrel. Make sure your flash suppressor is tightened onto the centering guide threads on the backside. This will enable you to turn the die down on the barrel. Turn the die until it just cuts into the end of the barrel. Now remove everything and look at the barrel. you will be able to see if it's off. Now take a nice sharp flat mill bastard or needle file and true it up, it's not as hard as it sounds. Once you get it pretty close the die and centering guide will true it up exact. Make sure you use cutting oil (50W or heavier) and rock the die clockwise and counterclockwise when cutting. This will keep your die teeth clean of debris and chips, resulting in clean threads. Degrease your new threads and cold blue. Oil the newly blued threads liberally and turn on your A2 suppressor. You are good to go. Photos of mine in ''MY NEW 580". Good Luck!!!!My A2 suppressor I notched teeth on, for fun......Big Grin

What were you watching on TV? Re-runs of The Golden Girls?