not even close.....
a semi auto 303 british would be a converted auto Bren gun. Pretty hard to compare that to an SKS. That is not even considering the cartridge comparisons.
Back in the day it wasn't uncommon to see Finn SVT 38s and 40s commercially converted to 303Brit.
I had one for a while and it functioned perfectly with decent ammo. The odd time, it would push the cartridge out of the magazine, which was close but not quite perfectly set up for the rim diameter of the 303 Brit, which was appx .040 smaller. This wouldn't happen with FMJ ammo, it was the lead tip spire points and round nose hunting ammo that would hang up on the lip of the feed ramp.
It was a lovely little rifle and quite handy as the barrels had been cut back.