Short bbl rob it off and maybe I should concentrate on post-stroke stregthing thing and forget the 22 mag?
That would be my advice. The 22 Mag from a short revolver barrel will be roughly equal to a 22 from a rifle. Better than nothing, but not nearly as good as something bigger.
It's not clear from the original post if your limitation is hand strength to pull the trigger or dealing with recoil.
If you must go 22 Mag, get some of the new ammo designed for handguns. 22 Mag rifle ammo is loud and has amazing flash when fired from a short barrel.
https://www.midwayusa.com/product/2...ster-magnum-rimfire-wmr-40-grain-hollow-point
https://www.midwayusa.com/product/4...-grain-bonded-jacketed-hollow-point-box-of-50
https://www.midwayusa.com/product/9...ire-wmr-45-grain-flex-tip-expanding-box-of-50