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AR-10 Proof Carbon Fiber 20" .308 Load Dev

MonstreSacre

Private
Minuteman
Oct 14, 2018
2
0
Chambersburg, PA
Hello,

I have a 20" 1:10 Proof Research carbon fiber 308 barrel on my AR-10 platform and I'm working up a load of Varget, Federal 210M, virgin Lapua brass, and 175gr SMK. The Sierra manual lists 36.3-41.7gr for that recipe, yet Hogdon lists 43gr as starting and 45C as max. I went to 42.7gr yesterday and could see the ejector mark on the base but I think the primer looks ok. Velocity was 2523fps. I'm not experienced enough to truly know pressure signs though.
Does anyone else have this barrel and can offer advice? Here's what my 42.7gr load looked like. Think I can go further? I don't know if there's an accuracy node around the corner to make it worth it or not. There seemed to be one at 41.8-42.1 since the SD/ES dropped to single digit and fps dipped.
IMG_2309.jpg
 
I settled on 42 gr varget on my AR10 .308 loads in lapua brass with 175 smk. Was also getting ejector marks past that point. Replace your primer on that shell with the marking, see if the pocket is still tight. Mine got so loose I tossed the brass.
 
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