Boring a rifled barrel smooth

[SuperCracker]

Quick machining related question.

I have a couple of 6" drops from a .58 GM rifled barrel I'd like to bore out to .60 or .62 smooth for a pistol. I have a lathe and I'm decent with it but I haven't faced this kind of boring issue before so I figured I'd reach out to the more experienced here.

Once I get the bore centered up in the 4 way is there a special bit (different angle or tip profile) to use that would work better for the first pass to get rid of the rifling before coming back with a reamer. I have a hard time not picturing the lathe chattering itself across the room as soon as it engages the rifling. lol

[Steve-In]

If you can find a reamer cheap enough you should be able to use it.  You are only taking out .020 for .600.  You probably need 2 reamers for a .62.  I have had real good finishes using a left hand spiral, right hand cut reamer.  Keep it well cooled.  Run about 150 to 200 RPM and feed about .020 per rev. 

[wmaser]

I had the same concern when reaming my first rifled barrel . I use a traditional reaming bench and hand forged bits and found that the fast twist of the bits does not impact the slower twist rifling, but cuts as if the rifling was not even there. Now I think you might run into trouble honing that barrel with an armorors bit without first removing the rifling. I never tried that but I'd be afraid of breaking bits.

[SuperCracker]

Thanks. I was thinking I'd have to drill the rifling out and then finish it up with a reamer. It didn't occur to me that the angle between the rifling and the flutes on the reamer would help stabilize it and keep it from chattering.

Hopefully I can turn this into a (or a pair    ) nice, tiny little English pocket pistol with about  a 3" barrel for killing rats and snakes.

[Dphariss]

Thanks. I was thinking I'd have to drill the rifling out and then finish it up with a reamer. It didn't occur to me that the angle between the rifling and the flutes on the reamer would help stabilize it and keep it from chattering.

Hopefully I can turn this into a (or a pair    ) nice, tiny little English pocket pistol with about  a 3" barrel for killing rats and snakes.

Why bother boring them? At short range a slow twist rifle barrel will shoot shot well enough for snakes etc.

Dan

[B.Habermehl]

If you have a 5/8 dia reamer available, I would simply bore cut using a boreing bar in the tool rest to about .005 under finished dia. About 1/4 or so deep. Then ream with the reamer in the tail stock of the lathe. The counter bore will help you get a stable start. The bore will more than likely come out tapered. Measure and use the smaller end as the future muzzle. It will probably turn out to be the headstock end. BJH

[SuperCracker]

Thanks. I was thinking I'd have to drill the rifling out and then finish it up with a reamer. It didn't occur to me that the angle between the rifling and the flutes on the reamer would help stabilize it and keep it from chattering.

Hopefully I can turn this into a (or a pair    ) nice, tiny little English pocket pistol with about  a 3" barrel for killing rats and snakes.

Why bother boring them? At short range a slow twist rifle barrel will shoot shot well enough for snakes etc.

Dan

Mostly because the 2 originals I'm basing it on are smoothbore and if I didn't build this as a smoothie it would drive me crazy. ................ I have issues. lol