CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.
I bought another Uberti SAA 45 Colt today 3-24-2012
Looking at chamber wall thickness at the rear of the cylinders, where the primary failure occurs with a chamber starting to split:
a) Uberti single action 45LC imported by South West Muzzle Loader Supply of Angeltown Texas, I paid $300 gunshow 2012:
0.090" ~ .095" to the outside
0.041" ~ .045" between chambers
b) Uberti single action 45LC Cattleman imported by Iver Johnson Fitchberg Mass, I paid $255 gunshow 2004:
0.059" ~ .064" to the outside
0.044" ~ .046" between chambers
c) Ruger new model Blackhawk 45LC I paid $300 in 2004 gunshow
0.071" ~ .074" to the outside
0.059" ~ .061" between chambers
d) Smith and Wesson 25-2 manufactured 1970, I paid $360 in 2002 + FFL
0.061" ~ .064" to the outside
0.066" ~ .067" between chambers
I have blown up enough thin wall large bore revolvers and Elmer Keith blew up enough 45 Colt SAA, I can surmise that working up a load and looking for brass failure will result in the cylinder splitting before brass yields.
So my strategy would be to use the few that have blown up or many that did not blow up as data points to steer by [Work ups are expensive].
I know that in 1994 "Speer 12" did "Ruger and Contender only" loads that were 25kpsi and 25 c.u.p.
I have not heard anyone complain about those loads.
If I plug them into Quickload
300 gr Speer, 23.5 gr H110, 1.6", 45Colt -> 27.2 kpsi
300 gr Speer, 17.5 gr 2400, 1.6", 45 Colt -> 31.7kpsi
I know that in May 2000 Clark Custom Guns offered a conversion for S&W 25-2 revolvers from 45acp to 460 Rowland. They also offered Data to 39.2 kcup. That data and that service are still there 12 years later.
http://www.clarkcustomguns.com/460loadchart.htm
If I plug them into Quickload
12 gr Longshot 230 gr XTP 1.275" 460 Rowland or 45acp -> 57.4 kpsi
14.5 gr AA#5 185 gr Nos, 1.275" 460 Rowland or 45acp -> 41.3 kpsi [oi, have i shot this load enough times in a handgun]
If I try to boil the above information down:
a) Uberti: 0.045"
b) Uberti: 0.044"
c) Ruger: 0.059" and known to be good for 27.2k -31.7kpsi in Quickload = .46kpsi ~ .54kpsi per .001" of case wall
d) 25-2: 0.061" and known to be good for 41.3k - 57.4kpsi in Quickload = .68 kpsi ~ .94kpsi per .001" of case wall
If I try to extrapolate from that I would calculate that a .044" Uberti should be good for 20.2 kpsi ~ 41.4 kpsi
I have been shooting exclusively for many years now a load Quickload thinks is 21.4 kpsi:
Exclusive Uberti 4.75" Cattleman load for 8 years: 24 gr H110 250 gr XTP. QL predicts 21.4kpsi chrono 1220 fps
Some have said I do not fire enough rounds for that to have meaning, but it still locks as tight on all 6 as tight as any revolver I have every felt.
In the short Uberti it chronographs at 1220 fps which matches the Quickload prediction for velocity.
That load kicks so hard in the 4.75" barrel Uberti I have had to TIG weld some more height on the front sight.
That load kicks so hard in the 4.75" barrel Ruger that I have only fired it once in 2004.
I use another load in the 6.5" barrel Smith, 1.4" 24 gr H110 230 gr FMJ, kicks like a mule. QL-> 24.4 kpsi, 1384 fps
I have not fired the 5.5" barrel Uberti I got today, just set off a primed case to verify the firing pin.
