never got a clear decisive answer to the question as to what NHM stood for when i posed the question , i believe MAK stands for Modified AK as in they were once pre ban rifles that were caught in limbo of the Bush law of '89 and had to be modified in order to be imported to be classified as a "sporting rifle"
i know the 90 and 91 in the NHM models stand for the year of manufacture , at least that was the answer i received when i inquired that seemed logical , the only answer i ever received as to NHM in my opinion was someone taking a stab at it so i hold no water in it was New Heavy Model given they were "manufactured to the Bush "sporting Rifle" guidelines to import rather then the modifications retro done to facilitate importation as the Mak's , but still had the heavy longer barrels which were more than likely surplus Poly NM barrels IMO
its also my understanding if it is in fact a National Match it will say National Match as well as have the NM associated with the serial on the receiver , that may very well be changed for the NHM model ,not sure which sadly an example has escaped capture for my safe all of these years , but is always on my list to acquire
thanks for the compliment , i do take pride in the care of my girls , about every 6 months i one by one clean and freshly oil , and they do not go back in the safe after shooting until they are cleaned , even the AR's and i know there are those that will go 3 k without cleaning theres