So I've got this beautiful old Winchester '73 built in 1881. It came to me needing some tinkering & I have it running / cycling great - had to fit modern links & get the correct firing pin.

The problem is accuracy. The bore's got some pitting, but generally has decent rifling. The issue is that it slugs at .438 or so, not .428. From what I've gathered on the internet, this is quite common on these old guns. I've tried casting soft lead 200 RNFP, 214 semi wad cutters, 240 grain semi wad cutters - using black powder & Trail Boss. I can't get the thing to group at all with the exception of some loads I did with a layer of masking tape on the bullets. I know I can get custom molds to fit the oversize bore, but I'm tired of throwing money at it. I boogered up one mold trying to ream it out with a bullet & lapping compound, thinking I could get a couple thousands out of it. Didn't work for me.

Does anyone know of a relatively easy/cheap way to bump up the bullet diameter without resorting to individually paper jacketing each bullet? I'm thinking some sort of coating, but I don't have the set up for powder coating bullets.

Another thing I'm thinking is my lead might not be as soft as I thought it was. I don't have a hardness tester unfortunately.

Looking for new ideas to try.

Thanks