The KPY Shotshell Ballistic Program is not perfect. I asked the guy that built this program about lead shot deforming on impact and he said that is not figured in on the penetration shown for lead shot. So the actual penetration you get with lead shot is less than what the KPY Shotshell Ballistics shows.
He said that he came up with the KPY Shotshell Ballistics for steel shot and shot that is hard and keeps it's round shape during the shell set back and on impact.
When I first started using Remington HD BB shot because I couldn't legally use lead shot anymore on coyotes. I saw right away that the Rem HD shot out penetrated the lead BB, BBB and T shot that I had been using on coyotes. I was seeing way more broken bones an exit holes with the harder and denser Rem HD shot.
For checking penetration I shot some catalogs with lead loads and Remington HD and Hevi-Shot T shot loads. The harder denser tungsten alloy shot types out penetrated the lead loads by a huge margin.
Some of the pellet counts are off when using KPY. The actual pellet sizes can vary and if the density is a little high or low that will also make the pellet count be off some. I have noticed that KPY's T lead shot pellet count is not the same as the T shot I use to buy from BPI and KPY's 15g/cc #2 shot has a higher pellet count than the Federal Heavyweight #2 shot that I robbed out of the factory 3" Federal Heavyweight shells.
I shot lots of coyotes with lead BB, lead BBB and lead T shot from 30 yards to 50 yards away and I don't remember seeing many if any pellets completely passing through our 20 lb to 35 lb coyotes. Most of the time these lead shot loads left the pellets just under the skin on the opposite side of the entry.
For shotgunning coyotes I like to have my 40 yard patterns to be about twice as big as 1ASSASSIN's 100 yard T shot pattern pictures. From what I have seen from killing lots of coyotes with shotgun loads, I like to have over 70 pellets per shell. Having 80 to 100 hard and dense pellets per shell with a 20" wide pattern really helps to kill the coyotes quicker and more consistently.
Most of the coyotes I shoot with a shotgun are running shots not standing shots.
These below numbers are from KPY Shotshell Ballitics. I use 3.70" of gel penetration for what is needed to reliably kill or break down coyotes. KPY says to use 2.50" of gel penetration to reliably kill geese.
Lead T shot at 1300 fps gets 3.70" of gel penetration at 66.0 yards, at 66.0 yards, was 713 fps
Lead T shot at 1300 fps gets 2.77" of gel penetration at 100 yards, at 100 yards, was 558 fps
Lead BB shot at 1300 fps gets 3.70" of gel penetration at 46.1 yards, at 46.1 yards, was 792 fps
Rem HD BB shot at 1300 fps gets 3.70" of gel penetration at 62.4 yards, at 62.4 yards, was 726 fps
Fed HW 15g/cc #2 at 1300 fps gets 3.70" of gel penetration at 70.5 yards, at 70.5 yards, was 697 fps
TSS #2 shot at 1300 fps gets 3.70" of gel penetration at 115.5 yards, at 115.5 yards, was 581 fps
It's to bad that no ammo manufacturers have come out with lead coyote loads in shot sizes BBB or T shot. Both the lead BBB and T shot are big enough to get the job done and they have much higher pellet counts than lead number 4 buck has.
