1849 Pocket Dimensions, Cylinder Boring

[HNSB]

My Uberti 1849 pocket has never shot well. I ended up getting a .22 conversion for it and forgot about it, but recently I decided to see if I could get it to shoot better with balls and powder.

I always knew there was some taper in the cylinders, but actually brought it into the shop tonight to measure. The cylinders taper from .320 down to .314. Apparently they don't like changing reamers at the factory.
I measured the bore on the comparitor, it's .3095/.3198 land/groove.
So best case scenario, with a full chamber of powder, I'm maybe just barely filling the grooves. If the ball gets pushed down at all it swages down to under bore size.

I'm going to bore out the chambers, but what size do I go to? Straightening them up to .320/.321 lets me use .323 cast balls and just barely fills the bore, but I'm pretty much limited then to .323 cast. I could go up to maybe .325/.326 and try to see if .330 buck will press in (antimony and all) and that also allows me to use the eras gone conical which is .330 OD (right now they won't load, .320 is too much to squeeze into. Insert comments about your prom night here). I also have some concern about how much is too much over bore? Will .326 swage down to .320 safely in the forcing cone? Am I stuck at .323 forever? Why did Uberti pick such odd dimensions? Why don't they change a reamer with .007 of taper?

Thoughts appreciated.

[HNSB]

I got impatient...

I ended up just going to .321 and straightening it out. Even though I took less than .001 at the mouth, you can see how much got taken off at the bottom of the cylinder. I can't believe how much taper was in there.

And yes... I left the nipples in. ��
I haven't used this cylinder in about 5 years and couldn't find a wrench to fit.

So now I have straight cylinder walls that are .001 over bore diameter and will still work with a .323 ball (though may not shave off a lot of lead, we'll see).
I'm going to try sizing some of the Eras Gone .330 conicals down to get them to stuff in. I think .330 will still be too much.
I have to give up on my dream of being able to use .330 buckshot.

[dangt]

I think percussion revolvers have tapered chambers by design. At least the mouth is tapered to accept balls readily. Balls are soft lead. Easily sized down in loading. Obturates easily on firing.

[HNSB]

They have a chamfer at the mouth to help get the projectile started. In my experience, I've never had one with taper like this - the referenced .007 was below the chamfer (not including it - chamfer is about .01x45 deg).

This was shaving lead to .320 diameter (barely bore dia) and then squishing it down to about .316 at the level the ball seats on the powder charge. I've never used another percussion gun with taper like that. I can't see any benefit to sizing a ball correctly, then undersizing it after it's already in the chamber.

[Good Cheer]

I've been threatening to try out a stepped chamber design. The diameter at the mouth to a depth to suit bullet lengths I'd like to shoot, then a short taper (for bullets to seat into) to a slightly smaller diameter for the balance of the chamber. That way I could have a standardized bullet sizing diameter for various molds, alignment of the bullets to the chambers would be automatic and I wouldn't need to apply expanding force when seating the bullets.

[warren5421]

The tapper helps prevent chain fires! I have shot Colt cap and ball guns for 65 years and all real Colts and reproductions need the tapper. I have seen a cople of Brevete Colts with straight bore chain fire. The tapper is done to cause the lead to squeeze down and seal the chamber in the cylinder, it will expand up enough to fill the barrel when shot. If you don't use pure lead, it shoots a shotgun pattern. I would tell you to get a new cylinder