Fudd here. I have mentioned before how I've measured AR chambering to definitely set shoulders back. I got curious back when experimenting with crimping. I measured pre and post chambering seating depth with crimped and uncrimped and factory crimped rounds. After attempting the math of shoulder setback and measured seating depth, it appeared that uncrimped only got longer while crimped got longer and shorter. I will admit my crimping efforts were hampered by having case length/chamfer not conducive to Lee factory crimping, but ppu 193s behaved similar to my crimped handloads. Might mean something to those who believe in seating depth consistency, but I might have botched the whole experiment.... My uncrimped did shoot better than crimped, but again my crimps sukd.....
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