If it is a model 1894 it could be a 44 mag.
I look up Marlin in the Blue Book the Bible of guns. They never made a model 94 that was a Winchester model number.
the 1894 was made in 25-20 WCF, 32-20 WCF,38-40 WCF 44-40 WCF Newer gun 357 mag 41 mag 44 SPL 22 mag and then Cowboy action 1894 32 H&R, 357 mag,44-40 WFC,44mag,45 LC,38 SPL
Need to look at your gun all the info is on the Barrel model and Cal.