The Columbus, Ohio PD Ordinance dept., did extensive tests in the early 70's on Remington 870 riot gun patterns. They found that with #4buck the pattern could not expand bigger than 1 inch per yard from the muzzle. So the maximum pattern at 30 yards was 30". It was usually smaller and with Skeet or IC chokes substantially smaller. A small amount of testing was done just to confirm that 00 & 000 buck shot did not expand any faster than 1" per yard also. These tests were done in order to have on file certified results for policy choices and to my knowledge were never used in a trial. There were penetration test done on car grills, windshields, windows & doors, but I never heard any conclusive results.

I do know that in 1968 at the Ohio Penitentiary riots, When the penitentiary wall was breached, the first man through the wall turned down a 1928 Thompson SMG, a M-2 Carbine, and Rising SMG's, in favor of a Stevens 67 and a hip pouch full of #4buck. Several police departments (especially Columbus PD) and National Guard troops were involved, but all weapons and ammo were from the Ohio Highway Patrol armory, and everyone had their choice!

My own testing has lead my to use #4 birdshot or smaller in my in town condo as a HD ammo in the 870 and 97. The penetration of modern construction walls was far too great with #4buck. In several pre 1900 farm houses destined for demolition I fired #4buck, #4 birdshot and #7 1/2 birdshot down hallways, up staircases, and at 90 degree angles to walls. The walls were of 3 construction techniques. 1) Old rough saw 2x4 studs with wood lath and 3 coat plaster (scratch, brown and top). 2) older finish sawn 2x4 studs with extruded mesh lath and 2 coat plaster (brown and Top) 3) Modern pine 2x4 studs and rocklath (similar to drywall) with a topcoat. This is much harder than current drywall techniques!

No wall stopped complete penetration at 90 degrees of #4buck, #4 bird shot had a few pellets make it between the wood lath thru the second surface and metal lath. The rock lath walls stopped almost nothing at 90 degrees. At glancing shot down halls and up stairs, no shot of any size made it into the side rooms, this was because the studs absorbed any shot that penetrated the plaster. However on the wood and metal lath walls the 2 sizes of bird shot deflected of the top coat and ricocheted down and around the hallway!

I never had to "Test" my theories on people, but a few raccoons have been in my cross fire with #4 & #7.5 bird shot (Less that 5 yards) and needed no follow up shots! In my 32 year war on raccoons I've found they are tougher than many people at surviving well placed 38 special +P.

I hope this helps you plan ahead. Ivan