.357/38 Dies taper or roll?

[Falstaff]

Why are there two different 3 die sets from RCBS in the .38spl/.357 calibers?
One's a taper, one's a roll crimp, which one do i need? (I have a single stage press now but will be ordering a Dillon progressive soon if that matters)
I imagine I'll be using lead and jacketed bullets.

[BigBronco]

Most bullets for that caliber have a canalure, If using a bullet with a canalure a roll crimp is what you want. If the bullet does not a taper crimp would do however you could get by with merely flattening out the flare with the roll crimp die.

[Clownpuncher]

Depends on the type of bullet. If the bullet has a cannelure you roll crimp it. If you are using plated bullets or some other bullet without a cannelure then I taper crimp them if you have a taper crimp die or just knock the bell off if you only have a roll crimp die.

[wtkaiser]

And if you want to be a mite more confused, at least one company makes a tool that puts a cannelure in bullets that don't have them, so you could take care of the decision that way, too!

[Falstaff]

thanks for the help, advice

[CSACANNONEER]

A lot of shooters prefer to use a LEE Factory crimp die instead of roll or taper crimps. This is the one time that Lee dies are second to none. So, if you want to take the time to crimp in a seperate process, get either set of dies (although, I would recommend Dillion dies instead of RCBS) and get a Lee factory crimp die too.

[Quinc]

I just did my first batch of .38 and .357 Jacketed bullets with Lee's 3 die set. They worked great.