Hi GG, yes, it would be fun handing off ideas on the same work bench, that n a cold tall neck of choice! The 410 is such a mediocre shell to begin with in 3" that the 2.5 is not only super limited in loads and availability but quite neutered in power also.
Back when I was in 10th grade HS, I made a .410 double barreled pistol in metal shop. The shop teacher was pure jock and I just kept assuring him it was only for looks. The dual 9" barrels were made out of basic cold rolled bar stock and as far as specs, I just cut open a shell and drilled it to match the wad on the lathe. I only got a B+ because I never got around to making the wooden grip inserts. But I had it made to fire both barrels at a time with a T bar across the hammer. God knows how it didn't blow up with only brazing for welds. Now that 9 inch barrel was good out to about 10 feet at best as far as perforating cans but any farther it was pretty weak (bee bee's caught inside of a soda can) and that was with the 3" mags.
Those new revolvers are ridiculously under powered with a short barrel and shotgun pressures. A good dog can about out run the shot coming out of a Judge!
I guess yah got me going on that subject..... On the other hand, Iv shot a mess of red squirrels with a good full choke 3" 410 and some clean kills out to 35 yards no problem. The 2.5" is pure disappointment unless you want a rat or snake shooter. Now maybe things have changed for that 2.5" load since I burned some all those decades ago..... maybe, but 3's are everywhere n pretty cheap.
LC, That's pretty much the idea of the conversion. I sure would not ruin a good M or D SKS for the conversion tho. Iv got about 20 some rotten barreled Yugo receivers to play with so to the purist's all my projects are resurrections of the dead!
I think its these odd ball wonders that may in the long run pull in a lot more google-ers to the sight.
You see when admins get goin at it
and they are both still here.....
Life is good!