I believe the original feed design only allows a specific cartridge length. Unlike the Marlin 39 that has a seperate cartridge stop tripped by the cartridge carrier that allows S, L and LR, the Browning designed Winchester pump uses the cartridge carrier as the magazine stop. There were specific .22 short gallery models, .22 long rifle hunting models.
I have a Taurus pump in .22 WMR magnum and it will not feed the .22 WRF. I paid $204 for mine new, discount for shop wear, and find them listed at auction sites selling for $340 to $400.
It does have the "slam fire" feature: if you hold the trigger down as you pump the action, it will fire as soon as the bolt goes into locked position. Some folks are aware of this, a feature with early models of the Ithaca 37 pump shotgun (but not all variation of the Ithaca 37 or copies of the Ithaca). Most pump rifles and shotguns have a trigger disconnect and users need to be aware of the difference. I impersonated Lucas McCain once with mine for funsies at the farm: accuracy rapidly pumping slam-fire mode is poor.