Without a photo nd something to judge it by, pretty hard just to pull a name out of ye olde hat.
With that width, likely it would fit an early Lee-Enfield or something earlier.
Whether it's PROPER or not, I can't say. I have a leather sling on my SMLE Mark I*** and others on Martin-'Eneries and Sniders. This sounds closest to what I have on the SMLE, but likely it's wrong, anyway!
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