At one time I did some load experimentation with the .30 Rem in an M81 using various bullet types and weights, even cast bullets. I had several hundred .30-40 Krag military bullets (220 grain FMJ) and loaded them using Unique powder. I had suspected that the rifling twist wouldn't be adequate to stabilize the long 220 grain bullet, but in fact they shot fairly good groups at 50 yards. I experimented by raising the powder weight a little at a time until I got positive functioning of the action. The 220 grain bullet must be very deeply seated to fit into the magazine. I also remember getting good results with 130 grain jacketed bullets. The nice thing about using the M8/81 is that any bullet type will work as it does not have a tubular magazine.

"The stripper clips were supposed to be for military sales Rem was hoping to make in WW1."
The U. S. Army did in fact do some testing of the M8 during WWI for possible military use, but it was not adopted. Actually stripper clips were available prior to WWI. I have an M8 rifle advertisement from ca. 1909-10 that shows .35 Rem cartridges loaded in a stripper clip. For the .300 Savage, any military stripper clips for the 7.62 NATO, .30-'06, 7mm/8mm Mauser, etc. cartridges can be easily modified for use in the M81 rifle as the .300 Savage has the same rim diameter.