Opening the Cylinders ?

[Hylander]

Got a new Pietta 1858
The cylinders measure .446
Bore .451
I know this is the norm for Pietta, but I want the cylinders opened up for better accuracy.
Is there a tool I can buy or rent to ream the cylinders or someone I can send the cylinder to
to get it reamed to .450 - .452

 

[Rifleman1776]

I can't help. But just will comment that I always thought the ball in the cylinder was larger than the bore and reduced in size through the forcing cone to fit the rifling.
I'm no eekspurt on this subject though. Can somebody help us both out?

 

[Hylander]

I can't help. But just will comment that I always thought the ball in the cylinder was larger than the bore and reduced in size through the forcing cone to fit the rifling.
I'm no eekspurt on this subject though. Can somebody help us both out?

In the real world that would be the norm.
But for some reason the Italians like to make the chambers smaller than the bore, no idea why

 

[MSW]

just a thought ... and with the disclaimer that I've never done this with any of my revolvers, so I may well be full of you-know-what ...

try shooting a ball or two through the gun and into a soft medium, so that the ball will not deform or expand ... (I've been told that a thick phone book soaked overnight in a pail of water works well for this)

then take a look at the expended ball, and 'mike' it.

see if you're getting complete obduration - that it: does the edge of the ball expand to the bottom of the grooves? if it is, you may be trying to solve a problem that doesn't really exist.

the ruminations of an old codger waiting for the snow to quit.
free advice, and no doubt well worth the price!

:haha:

make good smoke!

 

[John Taylor]

This is a common practice. You can get a reamer here. Next you will need a fixture to hold the cylinder and a good drill press. I use a rotary table on the mill with a fixture to hold the cylinder

 

[Andyd]

see if you're getting complete obduration - that is: does the edge of the ball expand to the bottom of the grooves? if it is, you may be trying to solve a problem that doesn't really exist.

This is very good advice.

That said I too would like to hear from someone who has some experience with this.

 

[ohio ramrod]

Simple reason why. Most reproductions are not made for accuracy. Loading an oversized ball into the cylinder "shaves off" some lead fragments. If the ball is then fired through an undersized bore more are shaved off when the gun is fired. If the ball is undersized to the barrel the second "shaving " does not occur.. This second shaving can be quite dangerous if your wrist of your "offhand" or other body parts are close. Back in the late fifties I learned this the hard way and was picking lead out of my wrist for months. :idunno: :idunno:

 

[matt denison]

That's a heck of a nice set up!! Way better than what I've done in the past (separate for each chamber..)

The OP would do well to simply send his cylinder to you for the work-for a fee- of course. Heck, I might send some to you. :grin:

 

[Zonie]

It is pretty common for the Italian reproductions to have chambers that are undersize.

I might point out that the chambers are always larger than the barrels bore but they are usually .005-.006 smaller than the rifling grooves diameter.
For instance, a Uberti .44 cal. 1860 has a .440 diameter bore, .452 diameter rifling grooves with .446 diameter chambers.
A Uberti .36 cal. 1861 has a .360 diameter bore, .372 diameter rifling grooves and .367 diameter chambers.

An exception to this was made on a few of the Italian Target models that cost more.

Why they do this is beyond me. Maybe it is to accommodate the standard ball sizes on the market?

 

[Ed Wingenroth]

In most, Shooter's will switch from Ball to Bullet and that may be the reason to adapt for the "bump-up" during detonation..

The longer lead of entry help's to stabilize the shot for better accuracy !!! :shocked2:

Ed

 

[John Taylor]

If you are working on a gun with a thread in barrel you can make a dummy barrel to guide the reamer. This also makes sure the cylinder bore is lined up with the barrel.

 

[BGRooster1]

When the projectile leaves the cylinder chamber it should no longer shave any lead at all. It should swage down to accommodate the bore and grooves of the barrel.If it is shaving lead as it enters the forcing cone ,it is a chamber/barrel alignment problem and a pretty bad one.
Brownells reamers with a pilot are for us guys that don't have such a nice set-up.

 

[M. De Land]

This is the method I used on my 58 Pietta.
The trouble I see with indexing on a rotary table is that the chambers are not always perfectly equal distant from each other in relation to the cylinder bolt index.
The barrel spud does just as you said and aligns from the cylinder notch index to the existing frame and bolt. Not exactly a line bore job but pretty close.
Actually they can be hand reamed with remarkably accurate results if the workman can feel the cut in and knows from experience what their about.
Same as with file work. Mike D.