Newbie asks "how to tell the difference between a grease gap and a crimp gap?"

[Big_Blue]

I couldn't figure out how to search for this question, so hope y'all don't mind my asking what is probably a dumb question for those of you more experience at casting your own boolits.

I'm trying to figure out which bullet casting mold to buy for my first .45 ACP effort. I just finished reading the Lyman "Cast Bullet Handbook" and did not see an explanation.

When I look at a boolit mold like this one (http://www.lymanproducts.com/lyman/bullet-casting/mould-details.php?entryID=27), how do I know if I'm looking at a bullet with one grease groove and one crimp groove, or a bullet with two grease groves and which the loader will have to crimp over the top of the uppermost driving band?

Thanks

[longbow]

Not a dumb question, it is good to ask if you don't know.

.45 ACP uses a taper crimp, not a roll crimp as the cartridge headspaces on the case mouth. That boolit has two lube grooves. A crimp groove is generally smaller and often with an uneven bevel with a slope for the cartridge brass to roll over and a steeper leading edge like:

http://www.lymanproducts.com/lyman/bullet-casting/mould-details.php?entryID=21

That one has one crimp groove and one lube groove.

Again, you do not want a roll crimp on .45 ACP. I am no handgun expert but I am betting that the .45 ACP dies will not form a roll crimp anyway.

I am sure others with more knowledge than me will chime in shortly too.

Longbow

[dromia]

Lube grooves are symmetrical either with rounded or square bases. Crimp grooves taper towards the nose for the case to crimp into and are not symmetrical about the horizontal axis.

[runfiverun]

45 acp dies marked for the 45AR have roll crimp capability.