MP 45-270SAA HP vs RCBS 45-270-SAA

[justindad]

The MP version casts a 285 grain solid or 270 grain hollow point. Has anybody cast both of these? Does the MP version fill the case more, or does it result in a longer OAL?

[winelover]

As I understand it, the MP version is a clone of the RCBS SSA 270 solid. I use the same data for the MP mold, as the RCBS, in my Ruger 45 LC Blackhawk.

The other differences is MP version has optional HP pins. Both conic and penta, in addition to the solid. IIRC, MP offered a choice two different diameters, .452 or .454. Mine drops bullets at .454 diameter.........the throats on my BH are a .454 slip fit. If your lucky, the RCBS may drop at .452 diameter, depending on alloy.

I have cast with all three pin version of the MP mold. I don't recall a 15 grain weight variation using the different pins. No matter, if you use the data for the slightly heavier solid.

Winelover

[justindad]

Thanks Winelover. The difference is only 5.6%, so MP might have simply had a sample mold on the heavy side of manufacturing variance.

[Bigslug]

I hit this thread on curiosity and that prompted more curiosity-generated browsing. Hope somebody with more knowledge chimes in. . .

The RCBS is a much-copied design, and they called it an SAA presumably because the crimp-to-nose length is compatible with .45 Colt Peacemaker cylinders. . .

Accurate Molds has several .45 offerings that claim that nose length dimension is .375", and they're measuring from the meplat to the front of the crimp groove. NOE's similar bullet is shorter in that area.

The MP website description of your SAA mold lists the nose length as .416", but it isn't showing a blueprint to indicate exactly where on the crimp groove they're calling it.

It made me go "hmmmmmm?"