I have 3 katahdins: 209x50, 444M and 12ga -20" turkey.
All have mt's. I use the 209 & 444 on pistol frames.
Tried the 12 ga that way. regular loads ok, but you can't hang onto 2 oz turkey loads even with a thumb hole stock.
209 does not shoot 200 gr shock-waves well. I need more time with different bullets. Recoil is mild with 100 gr 777 both as pistol or rifle.
444 as a pistol works well with hornaday 265's. recoil is less than my 375 jdj contender. 1" groups with 2x7 burris.
I never shot it as a rifle. In my zone I can shoot it as a pistol but not as a rifle??
I have not chrono'd any of the K's yet but the terminal performance has been good. deer seem just as dead as with longer barrels.
Unless your shooting extreme ranges, I doubt the short barrel will disappoint. They sure are a nice carry. I sling both rifle and pistol upside down on my off side, grabbing forend with off hand, letting sling wrap around elbow for support.