Pietta 1858 New Army Revolver .44 Cal 8" barrel

[Sun City]

I've been shooting handguns a loooongg time; but never messed around with any BP revolvers. I bought the above described revolver last year and I am very impressed with the quality of workmanship in it. Locks up tight at full cock position, smooth matchup with no visible gap betwixt the forcing cone and the end of the cylinder and what was really amazing to me has been the accuracy. Shooting at 45 yards out of my truck, as my ankle is askew at present, and resting my hand over the window frame, twice now I have fired two six shot groups less than the size of my hand palm. I'm using Hornady .454 swaged round balls and shooting 38 grains FFF Goex powder. My hats off to the guys at Pietta!

IMG_4703 by Sharps Man, on Flickr

 

[rodwha]

I've been shooting handguns a loooongg time; but never messed around with any BP revolvers. I bought the above described revolver last year and I am very impressed with the quality of workmanship in it. Locks up tight at full cock position, smooth matchup with no visible gap betwixt the forcing cone and the end of the cylinder and what was really amazing to me has been the accuracy. Shooting at 45 yards out of my truck, as my ankle is askew at present, and resting my hand over the window frame, twice now I have fired two six shot groups less than the size of my hand palm. I'm using Hornady .454 swaged round balls and shooting 38 grains FFF Goex powder. My hats off to the guys at Pietta!

IMG_4703 by Sharps Man, on Flickr

Try some .457” balls if you can. Because Pietta has such a large chamber diameter to barrel groove diameter difference more lead helps seal better and when comparing identical loads but using 0.451” vs 0.454” vs 0.457” balls the velocity only increased.

I’ve reamed my Pietta Sheriff’s model to 0.449” but I’d like to take on out to the groove diameter or close to it, 0.4535”. Might be a consideration if it becomes more than a cheap fun piece.

 

[Sun City]

Try some .457” balls if you can. Because Pietta has such a large chamber diameter to barrel groove diameter difference more lead helps seal better and when comparing identical loads but using 0.451” vs 0.454” vs 0.457” balls the velocity only increased.

I’ve reamed my Pietta Sheriff’s model to 0.449” but I’d like to take on out to the groove diameter or close to it, 0.4535”. Might be a consideration if it becomes more than a cheap fun piece.

At .454 there is a lead ring that's shaved off as a ball is seated and I'm thinking that if a .457 is seated that even more of a lead ring would be shaved off. The accuracy with the .454 is quite good so for the time being I will remain with .454! Thanks for your reply!

 

[rodwha]

At .454 there is a lead ring that's shaved off as a ball is seated and I'm thinking that if a .457 is seated that even more of a lead ring would be shaved off. The accuracy with the .454 is quite good so for the time being I will remain with .454! Thanks for your reply!

This is true, the ring will be ever so slightly larger as will the bearing surface creating friction fit. With a larger amount of lead there at the edges allows for better obturation of the gap between the chamber diameter and that of the grooves.

My Remington has had the chamber mouths chamfered so I don’t get that ring, it’s all swaged into the chambers. I truly hate fishing out those little pieces.

 

[Sun City]

This is true, the ring will be ever so slightly larger as will the bearing surface creating friction fit. With a larger amount of lead there at the edges allows for better obturation of the gap between the chamber diameter and that of the grooves.

My Remington has had the chamber mouths chamfered so I don’t get that ring, it’s all swaged into the chambers. I truly hate fishing out those little pieces.

I put a chamfer on my cylinder entrances last week. Another thing I plan on doing is I have a very smooth round stone in my tool kit and I'm going to use that to just touch up by hand each cylinder entrance that I put the chamfer on. Will also do the muzzle just to smooth out whatever burr might be there. I use a .44 caliber OPW against the powder when I seat it...then of course the RB. I apply a bit of beeswax against the front of each cynder. I don't believe it's necessary but for right now that's my regimentation! Beeswax down the bore can't help but possibly to reduce any leading that may occur although at the velocities we shoot don't think leading would be an issue!

 

[sdfdgfh]

First, of all... Welcome to the forum. This is the right place to be.

My Pietta takes .454 balls best

When you load the revolver, one of the things the ball does for you is to help seal the wall of the chamber to prevent hot gas from the discharged chamber from getting past the bullet and into the powder in the chambers which are not in line with the barrel.

To make sure this seal is as good as it can be, shooters like to observe a complete ring of lead that is shaved off the the bullet as the bullet is rammed into the chamber.

The ball should be large enough that you get a complete ring.

In addition, the ball has to thoroughly engage the rifling of the barrel. The groove diameter of your barrel should be somewhere around .446, so I am thinking that either ball will engage the rifling successfully. The Chamber diameter is right at .450.

But think about it. At .451, the most that the chamber will shave off the ball is .001 but at .454, you are shaving off .004. This shaving action actually takes the ball which starts out as a sphere creates a flat band all the way around the bullet. This flat area creates more surface for the bullet to engage the rifling.

Other members will very likely wade in with data from a scientific comparison of .451 performance as measured against .454 performance. I never did a comparison of bullet speed nor have I noted much difference in accuracy because I am not that good of a shot.

To me it all boils down to the lead ring.
__________________
Seek truth. Relax. Take a breath.

 

[Smokerr]

The dynamics are interesting, the larger the ball the wider the band on the bullet so its not all shaved off.

Also the shaving varies a lot between guns. The ROA has a straight chamber at .450. The Uberti 47 Walker (newish) has an opening that varies between .446 - to .448. Down 5/8 of an inch is .438.
My old 76 ASP has tapered chambers and shaves no lead.

I have begun to wonder if higher velocity will expand the lead better.

Ruger barrel (94) is .457 bore.

I do want to add the measurements have some uncertainty factor. Transferring from a telescoping bore gauge to a micrometer is not precise. Machine shops have a direct reading gauge for bores, never priced one, they gotta be trendy.

Lead balls are a bit hard to measure due to the nature of where the groves are.

I repeat the measurements a number of times and use what is most consistent.

 

[rodwha]

I have a 2013 Pietta Remington NMA Sheriff and I’ve measured my barrel by pushing a .457” ball down the barrel and used my calipers. The lands are 0.442” and the grooves are 0.4535”. I never measured the chambers as I sent it out and had them reamed to 0.449”. I have no clue what the older models ran, and of course the Shooter’s Model is certainly different.

 

[rodwha]

The dynamics are interesting, the larger the ball the wider the band on the bullet so its not all shaved off.

Also the shaving varies a lot between guns. The ROA has a straight chamber at .450. The Uberti 47 Walker (newish) has an opening that varies between .446 - to .448. Down 5/8 of an inch is .438.
My old 76 ASP has tapered chambers and shaves no lead.

I have begun to wonder if higher velocity will expand the lead better.

Ruger barrel (94) is .457 bore.

I do want to add the measurements have some uncertainty factor. Transferring from a telescoping bore gauge to a micrometer is not precise. Machine shops have a direct reading gauge for bores, never priced one, they gotta be trendy.

Lead balls are a bit hard to measure due to the nature of where the groves are.

I repeat the measurements a number of times and use what is most consistent.

The Ruger Old Army uses their .45 Colt barrels and should have grooves around 0.452”. While not an accurate measurement my calipers showed a chamber as 0.452”. They are not 0.450”. Ruger designed it properly with slightly oversized chambers as they should be.

 

[Smokerr]

I will defer to that. As noted measurements are very difficult to make and my tools are far from the best.

 

[Sun City]

Over the course of 70 years and learning revolver shooting from my Dad, I have seen modern revolvers that did not lock up as tight as this Pietta when in the full battery or firing mode. There is no slack whatsoever after the cylinder rolls into position. In addition to the .44 caliber OPW that I use when I compress the powder, as noted, there is another factor that comes into play to help seal the cylinder and that is obturation initiated by the powder charge to the rear of the ball. Without any doubt the shaving off of the lead ring contributes to this cause also. Even though the cylinder is a short distance compared to a rifle barrel when considering the obturation factor....it happens! And the accuracy is excellent!

 

[Eras Gone]

Congrats on a fine shooting revolver. I suspect your accuracy will improve even more with a lighter powder charge. The US Army load was about 25 grains and a conical ball. Most competition shooters are using about 20 grains with a round ball. Unless you are hunting and need the heavy load, lighter loads might save powder and be more pleasant to shoot.

 

[Sun City]

Congrats on a fine shooting revolver. I suspect your accuracy will improve even more with a lighter powder charge. The US Army load was about 25 grains and a conical ball. Most competition shooters are using about 20 grains with a round ball. Unless you are hunting and need the heavy load, lighter loads might save powder and be more pleasant to shoot.

I've got a .22 target pistol....if I want to shoot light loads! HAPPY 4th JULY to you sir!

 

[Smokerr]

Has anyone trapped round balls and seen if there is a better opturation with higher velocity?

I am thinking there should be but maybe a limit is reached below 1000 fps?

I know the various expanding base bullets do of course, ball or conical dynamics are ?????