09-08-2020, 11:58 PM
I loaded up some Hornady SST's with H380 and another batch with RL15. With the H380's I used CCI 450's, but just for the heck of it, I used BR4's with the RL15 loadings. No surprises with the H380: good groups at 29.1 and 2504fps and somewhat tighter groups with 29.7 grains that I got 2547.
Keeping everything else the same, but changing to RL15 and BR4 primers, I was beating Hornady's estimated MV's by a noticeable amount. With 26.9 grains, I measured 2577fps, compared to H's 2400; es was 30, sd was 12. Went up to 27.5 grains and got 2625 compared to H's 2450; and the es was 10 and the sd was 4. At 28.0, MV was 2681 compared to 2500 estimate. The es was 5 and the sd was 2. I'm going to have to really scrub this loading. I'll build them the same way and check them out to see if these were just an anomaly or the real thing. Through all 30 rounds at the different load levels, there were no pressure signs at all.
Keeping everything else the same, but changing to RL15 and BR4 primers, I was beating Hornady's estimated MV's by a noticeable amount. With 26.9 grains, I measured 2577fps, compared to H's 2400; es was 30, sd was 12. Went up to 27.5 grains and got 2625 compared to H's 2450; and the es was 10 and the sd was 4. At 28.0, MV was 2681 compared to 2500 estimate. The es was 5 and the sd was 2. I'm going to have to really scrub this loading. I'll build them the same way and check them out to see if these were just an anomaly or the real thing. Through all 30 rounds at the different load levels, there were no pressure signs at all.