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KCSO
08-20-2022, 01:39 PM
I do a lot of repairs to cap and Ball pistols and I have found that there are common problems that crop up with the Pietta guns. #1 is the problem of undersized chambers. The 36 guns run about 368 or so and the bores are 375. This makes them hard to load and usually gives then poor accuracy. The same for the 44's as I have a new Remington with .446 to 448 chambers. I use a fixture on the mill to ream the chambers to either .375 or .450 on the nose and all the same and it does wonders for accuracy. Couple this with a polished forcing cone and you have a real all day shooter that loads paper cartridges like a champ. By contrast Uberti guns have all been right on the money for chamber size.

Gtek
08-20-2022, 03:24 PM
Yes Sir, that one has puzzled me for years. The only thing I can think of for a reason is to possibly keep the pressures down, no other reason I can think of. The rest of the revolver clicks and clacks and have found other parts comparisons are usually on or within thousandths. I have a few ASM's that had .450"-ish cylinders and .465" grooves, finally found a .470" mold. Having that ball 0.00"-.002" over leaving cylinder is for sure a worth while exercise.

Harter66
08-20-2022, 03:50 PM
I guess I have the freak . The 58 has a .426×.440 barrel with .448 chambers .

.373/4 chambers and .361 groove in the 36 .

The ASM Dragoon has .447/8 chambers and a .445 groove .

I have an ASM 60 but it has parts missing .

Gtek
08-20-2022, 10:49 PM
ASM/CVA parts can be found at DEERCREEKPRODUCTS, my experience with them has been nothing but positive. Get that 60 up and running!

Jackrabbit1957
08-22-2022, 10:17 AM
Lately the last two Pietta revolvers through my shop have had more interesting issues than chamber sizes, which by the way I agree are not sized properly. Those two had arbor slots that were too narrow, the wedge would be stopped from pulling the barrel and frame together. This was causing the pistol to be real inaccurate. Once that was fixed and the pistol was properly tuned they became good shooters. I am a firm believer in chamfering the chamber mouths so the ball compresses into the chamber without shaving a lead ring off. I offer this as part of my tuning services but lots of folks out there believe it has to shave the ball to prevent chainfires. Shaving lead affects accuracy and makes no difference on chainfires as most are caused from poor fitting caps and lack of lube over the ball.

n.h.schmidt
08-22-2022, 12:07 PM
I think I got lucky with my Pietta 1860. Bought new about three months ago. Chambers .445-.446. Barrel .445. Both tight but good for a .451 ball. End shake at .0025 The euroarms revolvers I had/still have from the 70s all had chamfering on the chambers.No lead shaving .Worked just fine.

Good Cheer
08-22-2022, 09:55 PM
The chambers may be too small for the barrels but the newer Pietta's of the last few years really are a vast improvement.
Much better manufacturing, much better QA.