Gas Cutting/Leading

[4060MAY]

my friend made the mold no need to lap, the pictures show three different bullet dia. the groove is .381-,3815, the largest bullet that fits in the case is .381,Starline brass, WW is too small without reaming

OSO
actually the one that went Sideways was just over bore dia. patched .378, bore is .375.
bullet .367, patched 3 wraps onion skin, almost .002.
the first bullet shown is .374 dia.

the only thing that can be done is open the chamber up and throat it which is one of the next steps.

The last bullet that was shot I didn't put the picture up , because i'm running out of space I think.

The last bullet was patched .381, with a twisted tail, and there didn't seem to be any leading. 16/blue dot, but the cleaning patches are still torn. indicating something sharp in the barrel.

[oso]

. . . We tested 2 loads 16/2400 and 26/4895 patched 300gr bullet .374 dia. 13BHN, two wraps .002 onion skin, bore dia is .375, groove dia is .381. . .

Any suggestions how to stop the gas cutting? do we have to use the twisted method and cutoff with dikes? my 38-50 with Black powder absolutely does not lead with PP, but a 40-65 Sharps does the same thing the Uberti does, using 18/4759 400gr bullet.

I agree with Buckshot's statement in post #8 ". . . your boolit/patch combination is too small. . ."
My suggestion is still a boolit .376, patched and sized to .381 (since I understand you to say .382 won't fit.) I would do this before touching the chamber/throat.

[4060MAY]

OSO
I thought the purpose of Paper Patching was to keep the lead off the rifling, to prevent leading. if the bullet is over bore dia. the rifling should cut the paper and and the bullet will hit the rifling.
So far there is no indication that the patch is making it out of the barrel in anything but shreds.

With my 38-50 the patches are almost whole with the rifling showing on them. Not sure how to direct you to the other post showing my patches.
The bullet is .360 tapered to .364 and patched .369/.373 same alloy 11.5BHN, no leading acceptable accuracy, the difference I'm shooting 59gr 3F, with a poly wad. I also have a 3*incl throat w/.100 freebore .376 dia. IIRC

We will figure out the other gun, once we get the barrel smooth.

45 2.1
Haven't tried soft yet, that was next after smoothing the barrel, maybe next week, we are in the process of getting 14" of snow, and my friend lives 35miles from me.

[oso]

Yes, paper patching will let you get higher velocities with softer alloys and avoid leading. And the rifling does cut the patch but the bullet shouldn't touch the rifling, but engrave through the paper. My experience has been round holes at 200 yards, cut strips of uncolored patch paper and no leading.
My guess is that your boolit is upsetting at the start and your not just seeing gas cutting but possible contact with the forcing cone where you mentioned leading. I did notice the picture of your patch material and it appears ragged rather than evenly cut, and unevenly discolored. You mention boolit hardness of 13 but still not demonstrating an even "seal." I think of a paper patch boolit as a bore riding nose with a bore riding body, it still has to fit the bore snugly and start straight or it won't ride straight. I don't think a paper patch can make up for fit - I can mark a hard dried sized paper patch with my thumbnail but not a copper jacket. A softer alloy may bump up on firing, but you could also bump up the patched boolit when sizing (be careful, I've bumped some so much they wouldn't chamber.)
The reason I wouldn't touch the forcing cone/rifling is because I've had better performance with the patch just engaging the rifling on chambering (helping to start straight) and avoiding a jump to the rifling. You can always cut or wear material away, but you can't replace it.

I clip the twisted tail of the patch, but sometimes the tail tears and twists off and leaves the center of the boolit bare and these shoot as well as the others. I've read of leaving the center bare by extending the patch just a third of the diameter past the base and folding it down.

[4060MAY]

A guy I know brought over Bore scope, and we scoped the Uberti barrel.
After looking at the rifling and the machine work, it's surprising a bullet can pass through the hole that was drilled. The bottom of the rifling(Groove) has hash marks that looked like th barrel was drilled with a tap. My friend is calling Cimmaron (Uberti) to see what will be done.
I took a picture but we didn't have the camera set-up and it didn't come out very well
Later

[SharpsShooter]

Your boolit is too hard for the load intensity. Try some 40:1 Pb/Tin alloy.

I agree. I might even suggest pure lead. I had an IAB 74 Sharps that had a bore like you describe. I hand lapped it and the improvement was dramatic. Pity the lock was garbage and disentigrated shortly thereafter. Paper patching itself will help smooth the bore and I recently read of a gent lubing his patch with JB to do the final polish on a hand lapped job.

SS

[4060MAY]

Gun went back to Cimmaron, the Gunsmith ordered a new barrel
hope it's better than the one he is replacing.

We would have lapped it, but I don't think we could have gotten all the chatter marks out, and still have rifling left.

[Buckshot]

Gun went back to Cimmaron, the Gunsmith ordered a new barrel
hope it's better than the one he is replacing.

We would have lapped it, but I don't think we could have gotten all the chatter marks out, and still have rifling left.

................I'm contemplateing that myself. One more attempt at firelapping and if that doesn't take care of it then I'll be contacting Cimmaron. What I thought at first as being a choked bore (.373" atthe breech and .371" at the muzzle) appears to not be real choking. There is an issue about 1/2" inside the muzzle. A definate step.

It seems that quality is spotty. You may get a shooter or you may get a turd. I wonder if Uberti is sourcing it's barrels from Afghani hill tribesmen? Pretty bad when an $89 Mosin Nagant that was made when the Russians were getting the crap kicked out of them, will shoot rings around a modern made $1100 rifle.

...............Buckshot

[Southern Son]

Cimmaron sell Uberti in the US, don't they? I bought a Uberti Hiwall in 45/70. The barrel was quite good and the chamber fine, looking down the bore you could not see any imperfections. when I sluged the barrel, the slug travelled smoothly for the length of the bore, no tight spots, no loose spots either. I measured the slug, the bore was .451+ and the grooves went .457. I dont have any cerro safe so I could not measure the chamber. I could not find anything really terrible about the insides of the barrel. But the bloody thing just would not shoot, no matter what I tried. I ended up having to get a G.M. barrel put on.

Ron.

[4060MAY]

Buckshot
this barrel had two tight spots, and I mean the patch stopped and had to use force(hammer) to make it move. one 8" from the muzzle and one at the forend attachment.
FWIW The gunsmith that is working on the gun is sympathetic. should help.

SS
probably the best Mental Health thing that could be done.