In 30 years of shooting, I've experienced one slam fire.
Rifle:
PWS 10.5" upper on a DPMS lower. Slash's XH buffer and an XP spring installed to reduce gas-to-face when shooting suppressed. I had just installed a RRA NM 2 Stage trigger in this lower the day before from another rifle. The trigger was probably 15 years old with 2000 cycles on it.
Ammunition:
Handload using Tula KVB-223 primers. I've previously fired 5k of these without incident.
Scenario:
Inserted full magazine under an open bolt. Pressed bolt release and it sent a round into the berm. Finger was nowhere near the trigger. I don't recall what position the safety selector was on during the event.
Possibilities:
A.) Internet lore says these primers have relatively soft cups...it could be a slam fire from the floating firing pin.
B.) The heavy buffer with extra power spring landing hard when closing the bolt may have tripped the sear and allowed the hammer to fall of the recently installed RRA NM 2 Stage trigger. I've since removed this trigger, disposed of it, and reinstalled a mil-spec trigger and have been issue free for the past 500rds.
Given that I'd fired over 5k of these primers in the past without issue using a mil-spec trigger, and in the first day of using a recycled RRA NM 2 Stage trigger and this rifle has a slam fire, I'm leaning towards the latter. But yes, I've had one slam fire in 30 years.
