Modified military/hunting jacket medium/ large

A beautiful and slightly mysterious jacket, clearly military in origin but altered beyond recognition (to me at least). It's been shortened and the excess material  used to make pockets and the bullet holders appear to have been  added at the same time, It's raglan sleeved and has a throat tab. The label is unfamiliar/ undecipherable, but it appears to have dome age to it, I would guess 50s/60s and the fabric is a  tightly woven cotton, I susoect showerproof. It's marked and faded and a really lovely and unique piece. Sizewise it's on the cusp of medium and large, for guidance it fits me and I'm 6ft 2 and a 40 chest but please check measurements:

Pit to pit 22"

Length at back 27"