At a gun show a few weeks ago I picked up a 30 caliber barrel that the owner thought had been cut from some kind of machine gun. It is approx 24" long, tapered in roughly sporter contour, (approx .6xx" OD at the muzzle end).

It is not gracefully formed around the chamber area, but rather angles straight outward to a big fat unthreaded shank. There are some remnants of a chamber, but not enough to cast or say what it might have been. The outside was pretty rough, but the bore looked OK.

I got it home and slugged it at .308. My concern, however, is that although I had to rap a bit to get the slug started from the chamber end, after getting several inches in it cruised through the middle of the barrel with very little resistance. It didn't exactly free fall, but I could slide the push rod by hand with only light pressure. It then encountered more resistance at the muzzle end requiring light tapping to make it pop free.

I did this twice to verify it wasn't my imagination.

Although there are no outward indications of a bulged barrel, it is obviously not uniform. Could this indicate an unsafe condition? I know I would be better off buying a good quality barrel from a known maker, but I don't intend this for a high end custom build. I have a 9x20 Jet lathe and I was looking for a cheap blank to do my first full threading and chambering job on and match to an equal quality Santa Barbara action. For $20 this looked like a good piece to cut my teeth on and turn into an inexpensive shooter.

I just don't want to use anything that could be considered unsafe.

The chambering process might eliminate the tight spot at the breech end. Could/should I have the muzzle end bored or reamed lightly to make it more uniform? I guess another solution to eliminating the tight spot at the muzzle would be to shorten it. I don't remember how far back that extended and I don't want it too short. Also, if it slugged at .308 with the tight spots I wonder what it would be without them...

Any other thoughts on improving the safety and/or shootability of this barrel, or should I practice threading and then use it as a tomato stake?

Anybody???....

A little tight at the muzzle isn't bad. Start a new slug and mark the rod where you begin to feel slack in the bore. Place a rod on both ends of the slug, one as a hammer, and the other as an anvil, to squeeze the lead slug tight against the bore and then run it out the muzzle. Do it again, only this time from the muzzle back. But it doesn't sound too bad. .

Thanks Westpac.

I was waiting for someone else to chime in before I opened my mouth.

I was always told and read that a wee bit snug at the muzzle was normal and in most cases intended.

It's very difficult to tell how loose a bore is while shoving a slug down it. I mean an empirical number

The barrel isn't bulged, it is safe, and you
will get a chance to try your lathe.
It sounds like a couple of barrels I bought years back. They were from a Swede machine gun.
good luck!

It is not uncommon for a barrel to show indications of a tight spot at the breech end when such condition does not exist. Often the throater has displaced material rather than cutting cleanly. This results in some distorion of the lands at the start. The same sort of thing can happen at the muzzle end although any displaced material is usally gone with a few rounds.
Another thing worthy of mention is that a lead slug will allow you to feel .0005" very easily. Regards, Bill.