This a new rifle, less than 200 rounds down the tube. Model 12 FV in 223. Getting primer blanking (piercing) and partial blanking (cratering) even at low pressures. Primers are not flattened.
Also had two FTF but can't rule out shooter slamming the bolt closed a little too hard for the light trigger setting (accutrigger, NOT Target Accutrigger). Non firing rounds were ejected and checked for primer hit. None were noted.
I read that a light striker hit can cause this, not sure why but guess it has to do with not driving the cartridge forward against the shoulder far enough. I decided to disassemble the bolt and remove any excessive preservative oil, on the theory it was causing firing pin to move sluggishly.
I also disassembled the bolt head and used the opportunity to check headspace without the extractor or ejector mucking up the test. Headspace measured .004 using the Scotch tape method ( closed with effort on two layers of tape, would not close on three) with once fired brass (in the subject gun).
Firing pin protrusion measured .055, and Dia. measured .067 with some clearance noted between pin and hole, can't measure exactly.
Rounds that showed the most blanking also shot the tightest groups at 3250 fps using 25.0 gr of IMR3031 and CCI 400 primer, Federal brass from once fired from American Eagle varmint load.
FWIW: I also have a 12 BVSS in 223 and have a box of 100 rounds of this brass that is on its 9 reloading cycle and 100 rounds of new brass on its first reload. All new brass shows partial blanking, with some flattening with same load that older brass shoots with no flattening or partial blanking. I've never experienced a blanked primer in the BVSS.
All brass prepped after initial firing and weight sorted to +- .5 grain.
Any ideas or suggestions would be greatly appreciated
Edited to correct pin dia. measurement
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