i own a CM-9, but not a Sig 238, but from what i have read on other posts, the 238 is one of the EASIEST guns to rack the slide on, and it was a top choice for those folks who have trouble operating the slide on most semis.

my guess is that it is the contrast between the CM-9 and your 238/22 that is making the former's slide seem so hard. i'm NOT a strong person, but i didn't have any problems racking the CM's side even when it was new. the CM's slide might be a bit stiffer than the 'average' semi-auto, and coupled with the gun's small size, it may be more difficult to operate, but not substantially so, IMO.