.308 Remington XPL?

Good evening Gentlemen,
My first post so lets hope things work out correctly. I have this cartridge in my collection that I need to identify. Someone at some stage scratched “308 REMINGTON XPL” on the case - not visible on the scan. I cannot find any reference to such a cartridge. I came from the collection of the late Peter Skala, so it has to mean something? Bullet diameter is 7.62mm with case length 56.03mm.
Thanks very much in Advance
Daan

308remxpl

308remxplfull

Apologies,
Lets try again with the pictures

308remxplfull

308remxpl

Some folks use ‘xpl’ to denote ‘experimental’…I’ve also seen it used less frequently as shorthand to denote ‘exploding’. Other than that, I have no info on the origin of the cartridge.

It doesn’t appear to fit in with the standard 7.62x51 development chronology.

I’d guess that it was an earlier cartridge, perhaps a shortened .30-06, but the late .30 Light Rifle style base (.300 Sav with widened extractor groove) speaks otherwise.