I can't speak to the recoil of a 3 1/2 shell, but you did mirror my thoughts on the "One Shot" thing. The way those buggers move, once the first shot is fired you ain't gonna get another shot, most of the time! If you're goin' for an accessory barrel, the TDC 12 or 20 is the way to go...and you could always add on the HI-VIZ clamp on sights for turkey huntin'.
Just my $.02
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