To crimp or not to crimp?

[rtp]

Double the case wall thickness and add the bullet diameter to get the optimum measurement.

Double the case wall thickness plus bullet od = no crimp. It should be a couple of thou under that and within the range provided by SAAMI.

The bolded part is exactly what is being said - you don't want, nor 'need' a crimp on 9mm.

I believe even BE calls this out on one of his videos/DVDs, exactly as Sarge stated - double the case wall thickness + width of bullet = done. Remove the flare, don't actually 'crimp.'

[Sarge]

Double the case wall thickness and add the bullet diameter to get the optimum measurement.

Double the case wall thickness plus bullet od = no crimp.

No Crimp. Exactly.

[ltdmstr]

In reality, .001 or .002 is essentially no crimp. So it's not a big deal. What really is important, and was mentioned above, is that the case is sized adequately. I see a lot of guys (although much more so with .40 than 9mm) who have bullet setback and think they can prevent it by adding more crimp. That doesn't solve the problem and usually makes things worse.

[texasref]

As far as I know, ther's not a round in the world that does not have some sort of crimp. ltdmstr is correct in that SA should be taper crimped.

[RDA]

As far as I know, ther's not a round in the world that does not have some sort of crimp. ltdmstr is correct in that SA should be taper crimped.

I have bought lots of factory ammo that didn't have a crimp, the case is straight at the mouth and you can clearly see that the inner lip/edge of the brass does not disturb the jacket of the bullet.