Thread: What causes key holing in sub loads

@Bill999 thanks for the photos the bullet looks to be a flat base and the two red rings are lube. The third groove is a crimp groove and shouldnt be lubed. A gas check is a little copper cup crimped onto the bullets base there should be a recess to allow this.
The recovered bullet shows one rifling groove that looks to extend up to the mushroom.
The bullet is what is called a bore rider where the nose of the bullet is just land diameter with the grease grooves being slightly over groove so for a 308, the nose is usually 300 to 303 with the lube grooves being 309-310.
At that length they should stableise in a 10 twist but I have found that some rifles are quite picky about what they eat with cast bullets. The expansion looks normal for a lead bullet made from hard alloy.
I suggest you have chat with shooter nz about other cast bullets. I run a 170 grain round nose ungas checked in my 3030 and 308 over 10 grains of blue dot if thats any help. Flat nosed bullets feed fine in the 3030 as thats what the design is for but you need an ogive to run the bullet up with most box mag rifles.