The Hunter was made in 75 and then 85, wood stock and blued metal, also Hunter stainless, Hunter stainless laminate, Hunter stainless synthetic. Think the Hunter bit really just refers to the general dimensions and weights of the rifle, ie normal barrel profile.Made in differing action sizes from XS to L.
I have two 75 Hunters, a 223 stainless laminate and a stainless synthetic which started as a 243, but will soon return to me as a 308.
The bolt locking lugs are also a good indicator of models with the pre 75's having a conventional twin locking lug arrangement and rotating bolt guide rail. 75 & 85's have three locking lugs and no rotating guide rail. If you have been offered an earlier m591 Hunter these are superb quality rifles with the 75's being their equal. Unfortunately the 85 is of lesser quality in my opinion.
i own a 85 hunter in .243 and its only ever given me 1 problem which was the screw going through the action and stock came loose once and thats it other than that its never missed a beat and is extremly acurate with the 90 grain sako ammo i put through it grouping well under a inch at 100yrds infact its more like under 1/2 inch if im honest i would highly recomend the rifle as would many others and the caliber to as well, i know .243 isnt everyones cup of tea but i wonder how much of that is people just wanting a bigger gun .243 has done me fine on deer upto fallow and i would quite happly use it on a red if i ever got the chance