This is probably my last "testing" reply here as I think I've found a load I can make a bunch of that is accurate, cycles, and hits hard. For anyone that skipped to the end I'll give my whole recipe.
18" GLFA AR with mid gas, 1:24 twist. Rebel DFNDR 45 suppressor.
Lee C457-500 bullets cast either with straight coww or a 50/50 mix of SO and CO and 2% tin. Checked with Sages tall aluminum checks and sized to 452. Powder coated then sized again to .452. Seat to 2.13" and crimped with Lee FCD.
I got to the 100 yard range and brought some previous loaded either 22.5 or 23 grain SWBO bullets to run as a control and also loaded up loads of 26 and 27 grains SWBO.
23 grains 1128 avg
1112
1146
1129
1126
1129
- 23 swbo
- PXL_20210307_213134470~2_copy_470x512.jpg (108.97 KiB) Viewed 5913 times
26 grains 1289 avg
1261
1285
1318
1306
1275
- 26 swbo
- PXL_20210307_213231698~2_copy_483x557.jpg (115.7 KiB) Viewed 5913 times
27 grains 1355 avg
1346
1368
1354
1354
last round wouldn't chamber
- 27 swbo
- PXL_20210307_213136975~2_copy_359x467.jpg (81.82 KiB) Viewed 5913 times
All bullets were fired from a magazine and cycled with a normal (H2?) buffer, no need to use a light buffer or spring when running suppressed.
I think the suppressor added a few fps to the 23 grain load from what I remember. I'm most likely going to stick with the 26 grain load, however, I'm going to want to see how they shoot in the summer heat as well. I'm always a little skeptical of the velocity and pressure on a cold range day vs a hot day. Either way, they are as accurate as I could hope for. Better yet, they have a perfect hold over in my scope from my zero with the 300 grain NOE bullets (link below). NO SCOPE ADJUSTMENT REQUIRED, 300-500 GRAIN. I feel like I've struck gold here. My 2 cents.
http://450bushmaster.net/viewtopic.php?f=5&t=16533