I have an old gun...not quite collectable in 243 that has a small scratch in the chamber about 1/2 the size of a match head. It has sentimental value and I only shoot it a half dozen times a year. Can I put a dab of JB weld in the scratch and smooth it out w/sand paper wrapped around another cartridge. It bothers me more than being a problem w/the gun firing and ejecting. What's the consensus.

I'd be surprised if it takes the heat, I'd surely ignore it.

If it were me, if it isn't hurting any thing, than no. I can always make it worse. YMMV

Had a friend with scratched chamber in a used gun he bought. Would not eject. Had to drive the empty out with a cleaning rod. We took a dowel and slit the end and inserted a piece of crocus cloth. Spun it with a drill till it would eject. Took a few rounds but he's had the rifle for years and no more problems.

Fred

Another way to polish the chamber a bit. Put some JB bore compound and a little oil on a fire formed case and spin that a bit in the chamber. Have drilled out the primer pocket and tapped it for a cleaning rod and used the rod to turn the case.

Hard extraction? Anything noticed other than seeing the spot? Brass messed up? If not don't worry. Very fine sandpaper glued to a stick, just enough to take the high spot down. Doubt it is a big issue.

Roy Dunlap wrote about that, it works. Have done that with worn 400 wet-or-dry. Doesn't get rid of the scratch, polishing not grinding, but does something like break the edges of the scratch (I guess) so brass doesn't grab. Works for surface rusted/crudded chambers in balky semiautos too.