Roll Crimp vs Taper Crimp vs Factory Crimp - 45/70

[Blackhawk]

I don't reload for the 45/70 and want to buy dies. I want to load cast and jackets. RCBS has, I think, what I'm looking for I will just have to change the seater plug when going from round nose, which I probably wouldn't shoot much of and back to shoot flat nose. Does another company make a die that handles both? I thought I found a Redding set that may but am uncertain. Also does the taper crimp work best for cast and roll crimp for jackets? Also I can't locate info for the Lee factory crimp, is that a roll crimp? Can someone dicuss the type of dies and crimps used?

Johnny

[Griff]

Crimping gets discussed endlessly. And it's not very well understood. There are three basic crimps, the taper, which is most useful in semi-auto cartridges which headspace on the case mouth. Roll crimp, in which the die "rolls" the mouth into the bullet, requires careful adjustment so that the roll occurs as the bullet is seated to the exact depth the crimp groove is located at. This can be done in two separate steps, and a 4-die set will allow that. And, IMO, when loading cartridges with thin bottlenecks, like the .32-20, .38-40 or .44-40, this is a smart way to go. Lastly, the "Factory Crimp", a collet type crimp, most useful (IMO) with bullets that don't have a crimp groove, or its not where you want to crimp the bullet. This doesn't take quite so critical an adjustment.

Neither a Roll crimp die nor a Factory crimp die is "better" for cast or for jacketed. But, rather, either could be best for you, depending on your ability to adjust dies, keep cases to trim-to lengths, just how you feel about the process of loading ammo and the bullet you choose.

However, with any of them you can over crimp and damage the case, usually on bottlenecked cases where the neck gets collapsed or the shoulder gets slightly bulged.

You can probably get away with using a "round nose" seater plug with flat nose bullets... many of my loads are loaded on such dies. A flat nose seater should not be used with round nose bullets... the probability of having the bullet rock off square to the case is increased.

[AJMD429]

Here's a thread on the Lee "Factory Crimp" dies - viewtopic.php?f=1&t=36654

I can't help but think that they are 'best' for most purposes, in the 'rifle' configuration. Other than the FCD, the only other system I've personally felt the need for is a 'taper' crimp such as for the 45 ACP or others which space on the case instead of shoulder or rim.

I suppose the cases last longest with a taper crimp though, so all else being equal, it could be the one to use if that is your priority.

[sore shoulder]

For the 45-70 you will want to either roll crimp or Lee factory crimp. Roll crimp requires more attention to case trimming for COL but not a big deal, cast bullets have a crimp groove just for it. Lee factory crimp is more forgiving and definitely what you want for jacketed bullets unless they have a cannelure. 45-70 is a good cartridge to reload in that it's pretty forgiving overall and pretty easy to get good results, vs the bottle necked cases that require more attention and can be finicky about seating dies etc.

The Lee factory crimp looks like a military crimp.

[Blackhawk]

Thank you gentlemen. After thinking about this issue last night and reading the link that the doc gave I too seem to remember something about the FCD trimming a small brass sliver of one of my 45C cases. But also keep in mine I did that back in '04 and have not been reloading since then. Even saying that I feel like the Lee will fit my needs just fine. I do seem to recall having to adjust the locknut on them quite often do to the rubber seal not holding as it should.

Johnny

[Grizz]

One more thought about crimping 45/70, the need and technique can change depending on what arm you're using. For a single shot rifle no crimp is necessary as long as the bullet isn't loose. For a revolver you for sure want a good crimp to hold the bullet against recoil so it doesn't lock the action. In a magazine fed rifle it can be very dangerous if the bullet seats deeper while it is in the magazine, increasing pressure. This is a possible cause of the mysterious ka-boom phenomenom.

[Blackhawk]

Something I've thought about since posting is the fact that I was not trimming my cases. That may have been the cause of the sliver being seen.

Johnny

[hondo1892]

I like the RCBS cowboy dies if I plan on loading lead bullets. They are designed for that purpose. As for the Lee factory crimp it's fine if your lead bullets aren't too large. These keep the overall diameter of the case in saami specs which can swage down a lead bullet. Just my 2 cents.

[KirkD]

For the 45-70, and a few other cartridges, I use the Lee FCD and am very pleased with it.