9 mm case bulge

[briandg]

...

[FrankenMauser]

If there is no canelure, how do you know how deeply to,set the bullet. I had a gunsmith tell me to seat to the shoulder of the bullet yet I see several examples herein submitted where the bullet is seated well above the shoulder.

Cartridge overall length is a balancing act.
The factors reposted by noylj all contribute to the end product.

In the example posted above in my photo (122 gr LFP seated to 1.090" COAL), the determining factors were:
-Suggested COAL in published data for similar bullets.
-Enough of the bullet in the case to give me good neck tension.
-Seated deep enough to not jam in the throat.
-Seated as long as possible while maintaining reliable feed and function.
-I don't crimp 9mm -- I just remove the flare. (So seating to a crimp groove, cannelure, or driving band [lead bullets with no cannelure/groove] is a non-issue.)

That load has run just fine through every 9mm that has ever gotten a helping. It's on the mild side, as far as power level, but the dimensions are just fine for standard chambers (and magazines and feed ramps).

One down side of that particular load is that there is exposed lubricant. That lube may pick up contaminants that could be abrasive to the chamber and barrel. Generally, I avoid such. But, in this case, I knew the ammo would be well-stored and primarily used for plinking under controlled conditions. So the risk and likely exposure level are minimal.