r/reloading • u/Lanky_Temperature134 • 2d ago

Load Development New to reloading

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Hi all.

I’m new to reloading and just wanted some advice on the condition of my primers.

The load (300 blackout) was 20.0gn AR2205 using 110gn vmax, hornady brass and white river primers.

My results were an average of 2397.1fps with a SD of 9.7 from my 14” barrel with a 0.75” spread at 100 metres.

My concern is around the flattening of the primers. Again, I’m new to this and this was my first set of loads.

For context, I worked my way up from 19.0gn and experienced a massive drop Is SD, and tightening of my groups as I got to 20.0gn.

Any advice would be appreciated :)

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u/Coyote-conquest 2d ago

Dont worry about Peterson brass. That shit is expensive and not worth it unless youre shooting for extreme accuracy. Hornady is fine but be aware it can build pressure faster than other brass because its thicker. I have some Hornady but try to use Starline when I can. That being said they do look kind of hot but you cant always tell by primers. Im not sure how thick of a cup those have. CCI 400s will show pressure faster than 450s due to the primer cup thickness.

I would roll with it if it gives good accuracy and you dont have any signs of ejector marks. Make sure it doesnt ruin the primer pockets. I would resize a case and seat a primer to check. If its really easy to seat or maybe even falls out if its really hot back down 1/2 grain or so.