Sorry folks I've read oodles of discussion about crimping and it's difficult to come out of it with an answer. I reload .45 ACP, 9mm luger, and .50 AE. I crimp about an 1/8 of an inch and have had no trouble with headspace thus far. Is this enough crimp, or too much? I figured with the huge recoil of the Desert Eagle .50 I would definately have to crimp. I don't have a max cartridge gage for it though. How do I know how much to safely crimp the .50 rounds?

I forgot to mention that I only TC on auto loads which from what I read is correct?

When I taper crimp I adjust the die until it touches the case mouth, then add a half turn more, fine adjust to suit.

The taper crimp for straight walled pistol rounds is NOT used to secure the bullet. It is applied only to remove the flare plus maybe a thou more.

I was under the impression that it helped with feeding and reliability as well as reduced the chance of bullet setback during action cycling?

Surprisingly, despite the power of the 50 AE, a firm taper crimp but not enough to deform the bullet at all, is sufficient to keep the bullets from moving under recoil. Perhaps this is because the gas operated action softens things up a bit.

Thanks that gives me reference to work with!

quote:

Originally posted by medic883:
I was under the impression that it helped with feeding and reliability as well as reduced the chance of bullet setback during action cycling?

Removing the flare is a must for "feeding and reliability" and has nothing to do with bullet set back, that is what neck tension is for.

Is neck tension controlled solely by how much you "belly" the case with the expander die? Sorry I'm not sure of the proper term for the beveling.

When you bell the case it opens it to slighly more than bullet diameter so the heel of the bullet enters the case instead of geting caught on the edge of the case mouth. Too much of a bell stretchs the case mouth and leads to splitting.

The tension is from sizing the case back down to the correct diameter.

The crimp isn't as much as to push the edge of the case into the bullet but to smooth it back into shape. If you pull a bullet and get more than a line where the case mouth is there is probably too much crimp. Closing the mouth back does grip the bullet more but not to the point where the edge of the case acts like a lock ring as it does in a cannalured rifle or revolver bullet.

For the auto pistols the case mouth is where the case stops in the chamber. Too much crimp will let it slip to far forward. Then you can get either high pressure from the mouth not being able to expand to let the bullet pass or the case may go forward far enough not to allow the firing pin to strike the primer. this is an extreem but what happens when you roll crimp an auto loader cartridge. In some guns the extractor hook can hold the case to help prevent this in others it may not catch the rim.

So if I'm having bullet set back is it likely from to much of the case mouth getting belled by the expander die? Or will that matter as much if I'm crimping it correctly?

I'd think not enough crimp but it woudn't hurt to look at how much you are belling too. No reason to over work the case mouth.

Thanks Sam!

I haven't asked which dies your using. Die set up varies a little from company to company. Also if you are crimping and seating in one die or two, or using a single stage and working in batches.

quote:

Originally posted by medic883:
So if I'm having bullet set back is it likely from to much of the case mouth getting belled by the expander die? Or will that matter as much if I'm crimping it correctly?

You cannot secure the bullet with a taper crimp on a straight walled pistol round. If you are having excess set back issues(how much) crimping will NOT fix it. A taper crimp is applied only to remove the flare plus maybe a thou or two to aid in feeding and reliability.
Again you cannot taper crimp your way to securing the bullet.

quote:

Originally posted by Sam:
I haven't asked which dies your using. Die set up varies a little from company to company. Also if you are crimping and seating in one die or two, or using a single stage and working in batches.

I'm using RCBS carbide three die set in a Lee Classic single stage press. Up to this point I've been seating and crimping in one operation. Even though its a bit more time consuming I may start crimping as the final operation in the batching process.

I see what your saying Steve, the Lyman manual I have states that in addition to feeding and reliability the taper crimp just adds some tension to aid in reducing set back. I'm not disagreeing with you, but that is why I'm here. I need to figure out the things the manual isn't telling me. Where do you suggest I'm making an error then? I'm using the smallest expander plug available and only belling the mouth enough to just start a bullet. I actually had to increase it some because I was denting cases due to not enough expansion.