Originally Posted By: keith
I don't know what diameter bullets are used in the .500 BPE rifles. .006" deep grooves in a .488" bore would put you right at .500" for groove diameter.

But the groove diameter of my .450 BPE rifle is right at .458", and I'm going to try to alter a .452" caliber mold to drop a .452" diameter bullet of about 300 grains that I can paper patch to groove diameter.

EDIT: I see references to either .510" or .512" diameter bullets for .500 BPE. I'm stumped too.

Hello Keith,

Thanks for the reply.

When the British marked the "gauge" like this one .. "40" ... was that intended to be the "bore" dia. or the "groove" dia.

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