glock212327
Sharpshooter
The Sub2k in .40 has amazingly harsh recoil. Probably due to the Sub2k being blowback operated, chambered in a cartridge designed for short pistol barrels with associated quick burn rate for the powder (i.e., impulse from firing a round is shorter and harsher) and having a hard plastic butt "pad".
That said, you can get aftermarket soft rubber butt pads and recoil buffers for it to mitigate recoil. I've got a rubber butt pad on mine and it is definitely more comfortable than the stock "pad". Can't comment on the recoil buffers but it is claimed they significantly reduce the felt recoil.
The .40 has better ballistics than the 9mm which is why I chose it over the 9mm.
What recoil pad worked I've been trying to rig one up that will still work folded up.