I have some Remington 357 Mag 158 gr JSPs which have a taper crimp rather than a pronounced roll crimp as they had in the past. I even seen 38 Spl +Ps with taper crimps and no roll crimps

Even Fed 158 gr LHP 38 Spl +Ps have taper crimps.

Looks like factories are making it easier for themselves regarding case length on their cases?

Taper crimp? Could be but I don't think so due to the fact that bullets in revolver rounds (especially magnums) need to be restrained from being pulled from the case during recoil. Taper crimping doesn't do that. Maybe some variation of of a profile type crimp. Back in the day, some bullets had a sealer which prevented bullet movement in the case.

Bruce

I had cast a quantity of 9mm 124 grain truncated cone bullets with gas checks. They have no crimp groove and are smooth sided like plated . Looking at them I tried some , sized.358 , loaded in 357 magnum and some in 38 special .
I used the 9mm Taper Crimp Die to apply a taper crimp . Fully expecting the magnum loads to "pull" the bullets forward, I checked the rounds after each shot. None pulled out with a load of 7.5 grains of AA # 5, I shot 25 rounds with no problem.
In the 38 special that bullet over 5.5 grains AA #5 showed no bullet pull either. I didn't use any sealer .
I expected the bullets to pull, that was what I had read....But you know what...you can't believe everything you read on the internet !
Taper crimped them and they didn't pull and the loads were extremely accurate . 357 mag.=15 shots into 1 3/8ths inch group. 38 special=12 shots into a 1 1/2 inch group.
I'm going to work with this bullet and the taper crimp some more, it's looking good !
Gary

Great input gw. I'm experiencing similar results. I still roll crimp when using tradional cast bullets with crimp grove.

...more on reloading forum regarding taper crimp.

Oh yes, if the bullet has a groove or cannelure I also roll crimp.
But if a bullet doesn't have one the taper crimp can be used .
Clueless as to why the factories would taper crimp, possibly it's a cost cutting thing, easier to set the machines to apply one , maybe the case length can vary more ???
Gary

I called Speer a few years ago to ask about this when I noticed some of their .38 Special +P rounds appeared to be taper crimped. I was told that they used a sealant to hold the bullet in place. I assume other manufacturers do the same. Lead bullet loads all seem to have a roll crimp.

Whether revolver reloads with a taper crimp will have bullets pull out under recoil will depend on neck tension and gun weight. With any given load, lighter guns will have more recoil and the bullet will be more prone to jump the crimp. I've also had this happen with thin walled .38 Special brass and 0.357 inch bullets that were not that tight a fit in the case.

I think what the OP describes is a swaged crimp. The lip of the case is squeezed on all sides to engage the cannelure on the bullet. A true taper crimp does not look crimped at all, just enough to remove the belling which facilitates placing the bullet.

Although there are some crimping dies which produce a swaged or squeezed crimp, I prefer to use a roll crimp. For one thing, a roll crimp doesn't hang on the cylinder when reloading, particularly with a speed loader or moon clip.

As noted above, a swaged crimp is easier and faster to automate in commercial ammunition.

Great points, thank you for sharing your experiences!

...had a test of .38 special loads and it only took a light crimp to keep the last bullets fired from backing out. Now if you use alloy guns or in .357s I'm not sure that will hold up, so a little crimp is good for me. Cases will last longer with less flaring and crimp.

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