FX Impact New.

Continuum barrel will not fit. Nice thing about impact is can change calibers down the road. Id get a 700mm .22

If you are going to wait until spring you would probably do well buying a used one if you can find it. The rate that FX updates their rifles, and the fact that the MkII has now been out for a while means that an upgrade will likely be sometime mid year. That being said, with a .22 cal you would be fine with either length barrel. I personally would go with the 700 because the impact is a relatively short rifle anyway and the extra length will let you run lower reg pressures while still maintaining velocities. If your looking for a shorter rifle length for maneuverability though, you would do fine with a 600mm as well.

If you want to shoot slugs I'd go with the new Impact MKII with the Power Plenum (available on all 2020 made rifles) with a 700 mm barrel. This rifle should shoot modest weight slugs at mid 900 velocities right out of the box.

Hank

If I didn't already own an Impact, I'd just buy a new version in the caliber you want. I own a Gen 1 and was about to buy a brand new one in .22. Then the Power Plenum came out and my course will be to upgrade my Gen 1 before I buy the .22.

Personally, unless I'm shooting bench, I'd get the 600mm barrel. The 700mm is about 4 inches longer, can be a bit more efficient to use, and gives some increase in accuracy, but if moving through brush, that extra 4 inches might just get in the way. In fact, if I was using it as a brush gun, I'd go with the 500mm. The results the Crown Continuum are getting with the short barrel is amazing.

Good luck!