Discovered something about the Win Mod 54 that doesn't seem to be mentioned in Pulp Guns Vol. 2.
It's got a clip guide!
I took a picture:
https://c1.staticflickr.com/5/4371/3...6fc2da0c_b.jpg
This led me to dig around in some gun forums to discover that the clip guide was on all Model 54's except the .22 Hornet and .30-30 guns.
This, it would seem, should change the Shots to 5+1(3) when using the clips. Since most of the rounds listed in the description share the same head dimensions, standard Springfield M1903 .30-06 clips should work for them. In fact, that's an M1903 clip and .30-06 in that linked picture.
.270 fits in the clips and will feed into the magazine (and the chamber!) but I think accuracy and velocity would be adversely affected by the .308 bore...