The Browning BLR was first introduced in 1971. Made in Belgium it was available only in .243W or .308W calibers. Production moved to Japan sometime during late 1973 or early 1974. In 1976 the .358 Win was added to the BLR lineup.
This magazine is not marked .358 because if was manufactured before 1976
not to upset the thread makes me wonder if a 358 will feed smoothly in it unless the throat diameter makes a difference i dont see why it wouldn't
The reason I posted the manufacturing dates is I received a PM saying it is a knock-off magazine...I know this is not true as the magazine with the rifle were purchased new at the end of 1971.
I would assume a .358 would feed fine but I cannot guarantee it. It is a rare bird magazine from early manufacture.
There was an aftermarket company, years ago, that briefly produced a plastic variant of this magazine. I only know because I did a bunch of research several years ago trying to locate an extra magazine for my 308. This isn’t a bad price since these things are like trying to find hens teeth.