Threading the end of a tapered gun barrel

I want to make a muzzle break for my gun. I am just learning to run my lathe. The question I have is how do I hold on to the tapered barrel so that I can turn the threads on the end of my gun barrel? Those with experience pleas help me.

Thanks, KT

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Mount the bbl between centers & turn with a dog?

Chuck the straight part of the bbl near the chamber?

Reply to
Nick Hull


You just had to go and push one of my buttons. That's "brake" as in "stop" or "halt", not "break" as in "bust". I hope you're going to "brake" your gun, not "break" it.

There's a number of ways you could do this. Turn precision plugs for both ends with centers and do it between centers with a dog, I usually do it this way. You could also chuck the breech end using copper pads and use a plug on the other end. You could also just run the center right into the muzzle and figure on crowning afterwards, I don't recommend this. If you've got an action hanging off the back end, you'll either have to pull the barrel or turn up a mandrel to fit the bolt way. I've also seen guys use a steady rest with a cathead on the barrel and pad the cathead's centering bolts. Seemed like a hard way to do it to me unless they figure they're going to re-crown at the same time. You could bore out an aluminum sleeve to match the taper of the barrel, drive that on the barrel with a little Loctite, put the barrel between centers and true up the outside, then put the barrel back through the headstock and use the aluminum sleeve for chucking. You'd want an off-end support on the other end of the spindle to center that end up, too. You could re-crown it that way, too. That assumes you've got a spindle hole big enough to take the barrel. Lots of different ways to do the same thing.

Between centers using the plugs has worked well for me.

Some states don't allow threaded barrel muzzles, CA is one. Check state and local laws before doing it.


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I do it by making a short steel bushing with a taper bore to match the barrel contour about 3" from the muzzle. The bushing OD can be whatever is convenient, but make the wall thickness at least 1/4" . The bushing is seated firmly on the barrel on a piece of heavy paper cut to fit the bushing bore. The paper protects the finish and gives a good friction fit to the bushing. Then chuck the barrel threads in your 3-jaw (brass or aluminum shim stock over the threads). Put a live center into the tail stock and engage bore at the muzzle. Install your steady rest on the lathe bed but moved to a spot away from the muzzle. Run the lathe at about 250RPM and true up the OD of the bushing, taking very light cuts. Don't be alarmed if the barrel OD seems to wobble as many barrels are not perfectly straight and many have an exterior that is not concentric with the bore.

Now move the steady rest to bear on the bushing and adjust to a close running fit with plenty of lubrication. Move the tailstock back and you now should have full access to the muzzle end for threading, recrowning, etc. The bore should appear motionless when the lathe is running. If it doesn't, you did something wrong.

If you have a non-tapered barrel, a split(one side) bushing with a clamp screw will work the same. Just make the bushing long enough so the steady rest jaws don't have to ride over the screw hole.


Reply to
R. O'Brian


Gee officer, I thought that was decorative grooving.

Reply to
Tim Wescott

I thought it was for installing a 'mussle lock" ;)

Reply to
Nick Hull

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