Fire lapping a barrel using valve grinding compound.

[TCLouis]

I would first slug the barrel paying close attention to how the slug "feels" as it goes down the barrel.

Try JimB's suggestion and load bigger boolits (greater diameter) before doing anything.

Bigger as sized and with paper patch . . . before BEFORE doing any lapping for sure.
I firelap EVERY gun I own, but with a compound far less aggressive than valve grinding compound of any grit and I have that up to 1200 grit.
I have a method I follow and use it for me and it makes me happy, but then I no longer share it.

[dubber123]

Lol.. I used 320 valve grinding compound from Permatex to lap many, many barrels. Granted, none were Lilja barrels to begin with, but they shine like a mirror after, and ALL have shown improvement from good to excellent. Anyone who has ruined a barrel using it is doing something WAY, WAY different than I am. I have a nasty, pitted barrel 32WCF revolver that went from 8" at 50 yards, to 3" at 50 yards, with only lapping. Your call, but I have had nothing but positive results.

[flounderman]

Apparently some people don't understand the problem. Your hole is too big to start with is why the bullets keyhole. Making it bigger is going to make the problem worse.

[waksupi]

Apparently some people don't understand the problem. Your hole is too big to start with is why the bullets keyhole. Making it bigger is going to make the problem worse.

Exactly.

[David LaPell]

Well, got around to pulling a .32-20 factory Remington round apart today. The bullet measures .308", which of course, is too small. Even all the reloading data out there I could find says a .312" bullet. I haven't taken apart a Winchester factory round, but that's next. I find it funny that my Winchester 1885 made in 1889 shoots 1-inch groups with the factory Remington ammo, but the 1892 deposits them all over the countryside. Of course, it's going to be about handloading the right stuff for it.

[indian joe]

[QUOTE=MostlyLeverGuns;4428279]Fire lapping can help, but start with a really clean barrel. Valve grinding compound is not good for fire polishing, usually too coarse. MidwayUSA, NECO, Beartooth Bullets - all carry fire lapping materials for firearms. Dave Tubb carries fire lapping 'kits'. A barrel can be too smooth, hard to do with most factory barrels and common fire-lapping kits when instructions are followed.

I am curious to know how a barrel can be too smooth???? I'm thinking lead boolits the smoother the better - not the case? please explain......

[dubber123]

Apparently some people don't understand the problem. Your hole is too big to start with is why the bullets keyhole. Making it bigger is going to make the problem worse.

No doubt that is the bulk of the problem. He also says the bore is pitted, and I have yet to see a pitted bore not be improved by firelapping. Just as I have never seen one ruined by the process either. It seems like the OP is on his way to figuring it out.