Jacketed Bullet Crimp

[ES13Raven]

I know with plated and coated bullets, you need to be careful with crimp (just enough to take the bell / flare out etc.)

How about jacketed bullets? The same?

Are JHP and FMJ more forgiving with crimp?

[nicky]

I just set my crimp & leave it. others with more experiance than me may tell you different. Maybe not.

[1SOW]

Straight wall semis don't get a crimp.  As you said,  the flared case mouth done to make it easier to seat the bullet just needs to be removed.
To answer your question more directly,  jacketted bullets commonly have a tougher covering than plated or coated.  It's some degree harder to damage jacketed bullets than the others. Taper-crimping to a size slightly smaller than the bullet diameter  (A thousandth or two or maybe three) "probably" won't damage the bullet enough to affect performance depending on your normal target distances and sizes.

Some advocate a more than minimum taper crimp to change bullet release/powder burn pressure characteristics.
Reloader's choice gained from experience with that bullet using their powders and press dies.

I've experienced that some bullet jackets are harder than others.  I find Montana Gold bullet jackets to be the hardest of those I load.  JMO.

[snakeye]

I crimp all my 9MM and 40 SW loads....the only reason I do that is I have tried no crimp at all and had failure to feed issues, they would hang up on the feed ramp on certain pistols, case jamming on the lip of the feed ramp....I went back to a slight crimp and no problems....

[Wobbly]

I just set my crimp & leave it.

Nicky's answer is the 'short-quick' answer. Typically, the taper crimp die is set .002-.003" below the SAAMI case mouth diameter and left there. The reason is that with auto-pistol rounds (especially 9x19mm) the TC is for the benefit of the chamber. If not changing guns, then I've been able to leave the TC unchanged regardless of the bullet being used. I'd much rather insure complete combustion using seating depth (a very easy thing to adjust) versus TC (a relatively tedious thing to adjust).

As 1SOW addressed, what can change with the bullet is the amount of case expansion. Case mouth "belling" or "flare" is most definitely determined by the bullet shape, diameter and material.

 

[Radom]

The "crimp" issue is dependent on everything else.  If you are careful with your cases (trimming, segregation, etc.), then a moderate taper crimp with FMJ is a matter of consistency.  The key is being consistent.  Your loading technique may not be perfect, but it has to be consistent and repeatable. 

As Wobby covered, the key is "moderate crimp" or .002" crimp.  More or less will affect the headspacing or the max peak pressure. 

A taper crimp (as opposed to a roll crimp) cannot "cut" the metal of an FMJ.  I'm pretty sure a roll crimp couldn't cut gilding metal, either.  (I've never come close to trying.)  It could dramatically affect the peak pressure, however. 

[IDescribe]

Of course, if you're using jhp, and there's even a slight bevel to the base, you can skip the bell/flare and the taper crimp altogether.

[painter]

Of course, if you're using jhp, and there's even a slight bevel to the base, you can skip the bell/flare and the taper crimp altogether.

As you can with all the Berry's RN offerings. I'm not familiar with the FP and HP offerings wrt base radius.