Remember these from above-Well 2nd picture is penetration tests with
them. Over 2000 for 320 gr weight in plastic cases..
3rd picture is an all aluminum version without brass center
from penetration tests. 198gr at about 2500 in plastic cases.
Now the locked on bases are not burnt and the reason I understand
is they use a thin card between seal and powder, up inside the
seal cup.This info and testing by US-S group in the EU.
The plastic cup seal out there might benefit from that, like
card disc inside the cup of the BPGS and similiar seals.Ed