So easy way is the L-M-C models all have the same grip(full-size) and different length slides.
The S has a shorter grip
Depending on the generation the L-M-C come with a full-size 17 round mag and the S comes with a 10 rounder.
L long slide
C compact slide
S subcompact, compact slide and shorter grip. Also this S hasn’t made it to the A2 series where the rest now have A2 variants.
pic below the two FDE and the black on the bottom are L9s
Middle black is a S9 and top black is a C9
Here is a S9 sitting on a C9 (same length slide, different grip,10vs 17 rounds)
The C9 mags can be used in a S9 but there will be a gap. The S9 mags look like they should be able to take more rounds but were limited by the awb and never fixed after. Also as of now you can’t get a A2 S9 so you won’t have the more aggressive and size swappable grip or the redesigned extractor.
That’s a great question for Case, from what I understand they are different but I don’t know the spring strength of a 40. I saw a 40 spring and the rod was different allowing for what looked like a larger spring.
Interesting. Its more of a question for my daughter. I have the steyr M40-A1 and a S&W 9mm. She finds the slide much easier to manipulate on the S&W but really likes the steyr. So, if she looks into getting a steyr C9-A2 she was wondering if it would also be stiff or easier.
Thanks for your input guys. You have been helpful.
Depending on which Smith and Wesson MP you have, like the ZE , Would be better for someone that does not have the strength to pull the slide back, one option that is available would be to change the main Spring out in a Steyr, in the 9mm guns you can go as Low as 12.5 lbs but you have to use Lighter ammunition loads so you don't rip the gun apart. 40cal or 357sig can be lowered to about 14 lbs
And just for those that want the reverse numbers
9mm can go up to a 22 lbs spring with 147gr 2x or 3x P
40cal & 357sig can go to 25 lbs . Tho you will need some HOT ammunition to make it run.
My biggest recommendation would be if you play with a Spring weight drastically as I noted you want to test your ammo selection To make sure you can cycle reliably .