In my P-10, the 124gr RMR "stubby" JHP push test to 1.080", so these get loaded to an OAL of 1.065". (So this barrel's chamber is very similar to my older SP-01 tacti-cool.) No feed issues were witnessed and all rounds resulted in receiver lock-back after the last round.
All the following test loads were run with Win brass and Win small pistol primers. All were loaded on a Dillon press using Dillon dies. All reported bullet velocities were the average of at least 6 shots. Velocities were recorded on a Pro-Chrono. Ambient temp was 30?F with cloudless afternoon light.
I was able to get out today long enough to finish this string for Earl...
Ambient today was 36?F with light drizzle.
RMR 124gr JHP W231 4.0gr 962fps
RMR 124gr JHP W231 4.1gr 993fps
RMR 124gr JHP W231 4.2gr 1029fps
RMR 124gr JHP W231 4.3gr 1045fps
RMR 124gr JHP W231 4.4gr 1052fps
RMR 124gr JHP W231 4.5gr 1078fps*
RMR 124gr JHP W231 4.6gr 1094fps*Although not shooting for accuracy, the 4.2 & 4.3 seemed to be the sweet spot.
All rounds resulted in receiver lock-back after the last round.
Lightly padded gloves would not allow the trigger safety to disengage !!And also this...
PD 124gr JHP N320 4.0gr 1013fps 1.100"OAL Fed#100 Primers
PD 124gr JHP N320 4.1gr 1032fps
PD 124gr JHP N320 4.2gr 1052fps
PD 124gr JHP N320 4.3gr 1083fps
All rounds resulted in receiver lock-back after the last round.