Last night while at the rifle range a guy comes up and asked me if i wanted a bag of old bullets naturally Yes. Got home and had diff. cals.But I havnt seen or heard of one --351 S L R --- 180gr soft point and some full medal jacket. Some Rem-Umc and Winchester rounds.

thats a headstamp from Dominion Cartridge Co. in Canada
it's .032 shorter than the .357 maxim, was used in the Winchester 07 autoloading rifle. Used a 180 gr bullet at around 1850 fps.
case length-1.380
case mouth- .377
case head width-.410
rim thickness- .050
inside diameter of the case at the base...just above the flashhole- .381

http://www.ammo-one.com/351WSL.html

If i'm not mistakin, I believe the 351 SLR aka 351 WSL was a winchester made caliber originally came out in the year 1907 and production stopped in I think 1960
SLR stands for Self loader rifle or self loading rifle something of that sort hang on to them may have collector value. I know of a rifle the winchester Mod 07 shot that caliber. But I dont know of any other guns that were chambered for it.

Thank you 8mm-06 and H D W