There doesn't seem to be much info out there for using 300-MP in 300Blk. And what is out there isn't consistent in results.
My limited background on reloading for the cartridge is subs and cast bullets. Using mainly Reloder 7 and some IMR-4198. Missouri's 245 gr and cast from Lee's 309-230 mold. 8 1/2 and 10 1/2 inch barrels.
I don't have any velocity readings, as my chony is down (lead poisoning).
My start load with 300MP was 9.2 gr., which locked the bolt back on last round. And had loads up to 10.1 gr., but stopped at 9.5 gr. I compared the firing pin impression to a known load in R-7 and stopped when they looked the same.
Accuracy, I don't know, because the ground solder on the red dot gave out, I have since fixed it. Also have flip-up sights now.
Any way, the Lee 230 gr. OAL seated is 2.250. Primer is CCI 400. And 9.5 gr. of 300MP. That load cycled reliably and kept subsonic.
My limited background on reloading for the cartridge is subs and cast bullets. Using mainly Reloder 7 and some IMR-4198. Missouri's 245 gr and cast from Lee's 309-230 mold. 8 1/2 and 10 1/2 inch barrels.
I don't have any velocity readings, as my chony is down (lead poisoning).
My start load with 300MP was 9.2 gr., which locked the bolt back on last round. And had loads up to 10.1 gr., but stopped at 9.5 gr. I compared the firing pin impression to a known load in R-7 and stopped when they looked the same.
Accuracy, I don't know, because the ground solder on the red dot gave out, I have since fixed it. Also have flip-up sights now.
Any way, the Lee 230 gr. OAL seated is 2.250. Primer is CCI 400. And 9.5 gr. of 300MP. That load cycled reliably and kept subsonic.
