I see you have declined to give us a MV of your loads, so I'll ballpark:
A 3" .410 can send 3/4 oz of shot out of the muzzle at about 1200
A 3" 12 gauge can send 1 3/8oz of shot out of the muzzle at about 1500
Put the same shot in either and a 12 gauge is more effective. Its physics.
This statement is patently false: "gauge equals killing distance, when in fact it doesnt, it just equals amount of shot in the air. Patterning(forcing cone, muzzle restriction, etc) equals distance."
Now, if you add the caveat that "TSS is a waste of money in a 20 or 12 gauge" then you are tipping the scales. That is like saying a .243 with a Barnes X will penetrate better on elk than a .300 Win Mag shooting 150gr Ballistic Tips. Yes, it probably is, but you have rigged the game. That is not a comparison of .243 vs. .300, it is a comparison of a mono bullet vs. a frangible lead one.
I've shot a bunch of the various non-toxic pellets, including TSS. I hunt waterfowl multiple days a week when the season is open.
I didn't decline its just pretty standard, 1100 +- for 13/16 #8-10 TSS, you can get steel and bismuth a probably up to 1300
TSS in
12ga 2.5 oz 1000-1200
20ga 2.0oz 1000-1200
with that said you can run 1500 with 1 3/8 of #9 TSS? Have fun with that…... Thats steel and steel is a joke. Hypersonics at 1700 where effective but hell on guns. with TSS you would run a 2.5oz load at 1000-1100
As far as patterning I dont know what to tell you, Nothing has beat my 28ga with #9 and #8 TSS. 410 is pretty damn close,
as far as what matters.
12ga 1 3/8 #6 lead is 307 pellets
12ga 1 3/8 #7 lead is 409 pellets
12ga 1 3/8 #4 steel is 263 pellets
12ga 1 3/8 #5 steel is 236 pellets
410 13/16 #9 TTS is 294 pellets
Id say #9 TTS performs similar to #6-7 lead and 4-5 steel range.
TTS volume is lower then steel and lead per oz as it weighs more soooooo you get over kill b/c as you run larger gauges you get larger loads.
12ga 2 1/2oz #9 is 905 pellet
20ga 2 oz #9 is 724 pellet
If you can get 20/12ga steel and even lead performance with out the same recoil, less powder and less report with smaller gauges whats the down side?
Anyway cooled of so I’m off to finish planting.