.357 SIG

[CCT125US]

Reloading press used (list modifications if relevant): Dillon 650
Caliber: .357 SIG
Bullet (Weight, Coating, Profile, Manufacturer): RMR 124gr JHP MPR
Powder manufacturer, type and charge; volume, type (ball, stick, flake):Unique
Dies used:Hornady decapper, Dillon powder through expander, Hornady seater
Primers used:CCI500 SPP
Cartridge Overall Length (COAL):1.150
Chronograph data (if possible):
Goals intended with this load:Accurate plinking round
Results - accuracy, smokiness, clean burning, flash, temperature, smell, brass deformation, etc.:
Problems encountered and fixes applied:Worked through some initial bullet setback issues through multiple chambering. Adjusted the powder through expander and the seat / crimp die to mitigate.
Anything of interest:


86570

[358156hp]

LEE makes a collet type "Factory Crimp Die" that should help you with your bullet setback. This is a spinoff of their rifle FCDs. I bought one, and it fixed that issue for me with the first use.

[CCT125US]

Info above using 6.5 gr Unique
P2000 .357
RMR 124gr MPR JHP

Velocity and setback testing

Measured starting OAL, re-measured after several strings:

1.151, 1152 fps
1.151, 1164 fps
1.151, 1146 fps
1.151, 1135 fps
1.150, 1150 fps
1.150, 1.144, 1175 fps
1.149, 1.150, 1158 fps
1.149, 1.146, 1146 fps
1.149, 1.150, 1.143, 1150 fps
1.149, 1.148, 1.146, 1162 fps
1.148, 1.148, 1.148, 1139 fps
1.145, 1.143 1.141 1165 fps

SD: 11.6 pleased with this.

Sharpied OAL on case, fired 5, measured the remaining rounds, loaded mag in same order, fired 3, measured remaining rounds.

Pleased with initial batch. A bit mild, but no noticeable bullet pull / setback under recoil.

Sellier and Bellot 140gr FMJ chrono:
1212
1221
1228
1230
1230