1858 Remington New Model Army Revolver

Gene wrote: Just got a Kirst 45 LC conversion cylinder for my Uberti 1858 Remington New Model Army revolver.  I need some load data for safe loads in this gun for .452 and .454 lead bullets.   Does anyone have any experience with these guns.  I can shoot a 5 in group offhand with 25 gn 3F at 25 yds, so I know the gun will shoot.  The new cylinder locks up good and tight...

Gene,

I have three Kirst conversions, but mine are in .45 ACP.  In the .45 Colt conversions you can shoot factory equivalent “cowboy” loads within SAAMI pressures.  If your revolver has the  fixed military sights, these are regulated for round balls, so you will want to shoot the lighter bullets to maintain point of impact. 

In my Remington conversion  250-gr. bullets shoot “on” at about 100 yards and are too high at short range to be useful.  The RCBS .45-230CM shoots closer to point of aim, but is still high until you get past 50 yards. Alliant's web site shows 6 grains of Bullseye as max. for the 230-gr. cowboy bullets in the .45 Colt.   I use 4.5 grains in .45 ACP brass with the same bullet.  You could use 5 grains as a start load in .45 Colt brass, or as the full load for Scofield brass if you have that.

I've had good luck in my Remington conversions loading .457 roundballs. I tumble these in Lee Liquid Alox.  My load in .45 ACP brass is 4.5 grs. of Bullseye, adjusting the seater to taper crimp the case mouth into the side of the ball just below the tangent. The seater die forms the exposed radius of the ball into a narrow driving band.  These button bullets feed fine from my .45 ACP converted Marlin lever gun, give about 750 f.p.s. in the revolver and 850 fps in the rifle.

In .45 Colt brass you can load .457 roundballs with 5 grs. of Bullseye, just pushing them flush to the case mouth, smearing a little bullet lube or Crisco over the ball, and sizing the loaded round in the Lee Factory Crimp die to remove the bulge caused by  the .457 roundball being seated in the .45 Colt case. 

Also good would be any of the 185-200 grain wadcutters for the .45 ACP if you can find a mould which casts large enough to fit your revolver cylinder throats.  I've had good luck with the Lee 200-gr. R.E.A.L. with 5 grs. of Bullseye.  That would make a nice mild load in .45 Colt brass.

If you don't have Bullseye, 5 grains of 700-X, Red Dot or TiteGroup will give similar safe results.  About 6 grs. of 231 should also be good and is in the right range.

While 8 grs. of Unique is fairly standard in the .45 Colt with 250-gr. bullets, I've found that  Unique doesn't burn as well with the lighter bullets.