Ok here's the recipe
Bushmaster upper and lower, Hydraulic buffer and Ross Schuler Brake (Awesome guy).
42 Gr.Win 296
CCI 450
Hornady once fired1.690
FTX 200 OAL 2.203
Light Stab Crimp and Light Taper Crimp.
35 degrees
Here's what came off the burner.
Average Velocity And I say average because you have to average these numbers out.
2330FPS
Extreme Spread 181.6
Standard Deviation 82.86
.84 4 shot group at 100 yards best group yet with 450 that I bought in Dec..
Question
Why does the best group I get come from such extreme spreads and poor SD?
The next best group I got was
38 gr 296
CCI 400
35 degrees
The primer caused a delayed ignition.
Why good group with that load to?
What causes extreme spreads like this?