ok, here is what i did find.. the 8M1 'effect' bullet is a hollowpoint. the hp is covered by the copper nipple. 8M1 and 8M3 are design designations. 3 is frangible and 1 is hp. the idea behind the M1 is that the nipple allows for penatration of a solid but upon hitting harder objects ( bone ? ) then the nipple colapses into the hp and it encourages the expansion of the hp cavity. boxes of ammo also marked "match" have closer tolerances and less spread of grain weight.
now thats what i know, here's what i think... silver bear may be trying to overcome some poor ballistic from the AK or whatever other gun that shoot this stuff ( 7.62x39/54 ) by some re-engineering of the function of a bullet.. the samples i have to measure 124 grains, .310 diameter with almost no deviation.
how they work on a "target" is another matter, but thier grouping would need to be checked out first.
glenn