12 Gauge Shotshells

11/24/25 Update - Added 2.75 inch high brass, 2.75 inch low brass and 3 inch high brass iterations.  The 2.75 low brass even has an 8 petal crimp.

I was doing some mid-season organization of shotshells in my ammunition cabinet, and started to get interested in the dimensions of the different shells.  It had been awhile since I'd had an excuse to model anything and I thought it would be fun to make my own replica 12 gauge shotshells.

I made two sets of them.  While the SAAMI specifications call for a certain folded length, I found that in practice actual shells consistently measured .1 inches shorter.  I found this across all brands, sizes and style of shell. 

I measured the following shells and found them all to be .1 inches shorter than the SAAMI spec.

• 2 3/4
  • Federal Prairie Storm, Kent Ultimate Fastlead, Federal Top Gun, Remington Nitro Express, A-Zoom Snap Cap
• 3
  • Kent FastSteel+,Kent FastSteel 2.0
• 3.5
  • Winchester Xpert, Blind Side 2, Final Approach

I don't have any shorty shells, but based on all the other lengths assumed they would be a little shorter in actuality so made an “actual” version of that right away too.

Shell Lengths (Inches)

I tested the 2 3/4 and 3 inch shells in a Remington 870 Express Magnum 3inch pump, a Baikal 3.5inch pump and a Benelli Super Black Eagle 3 3.5inch semi-auto .  All three guns cycled the shells without issue, however, the Benelli had a tendency to break the rim off the shell when it kicked it out of the magazine tube in preparation for loading when the gun was fired.  This was with versions that I printed in PLA using only 2 perimeters and 15% grid infill.  I'm going to print a couple out of PETG with more perimeters & infill and I'm guessing they'll work fine then.