BTW, what is key is a clear picture of the HZa stamp, see if you can get the sharpest, cleanest, clearest and most distinct picture possible of this eagled acceptance stamp. Look at the FP HZa on the barrel and receiver and if possible the lower buttstock, assuming any are clearly definable. There are numerous lists of the known HZa around, but this one is elusive and as far as i know only the second recorded, neither clear enough to make out the HZa location (HZa followed by a series of letters, typically a upper case letter followed by a lower case letter, - identifies the facility, typically a city or town, followed by a number, the number representing the inspector/armorer or shop (theories vary).
If you haven't gathered by now, not much is really known with certainty, the larger shops are better known, more examples and variations, the mom and pops are less known not only because so few made, but they were not long in existence, - prior to the nazis coming along, there were only three official HZa's, all technically illegal (though kind of like pot being illegal, everyone knew about them, no one really cared enough to get the Germans to move them and change their name, which is all the Germans would have done had they been spotlighted...), naturally once Hitler came along the Germans just just popped up these ordnance shops, as the list of conquest grew, so did the number or shops, so to the distinctions, some real depots, some more temporary (ordnance staffs) or small operations (the police and SS had dozens of shops, who knows how complex each shop was, only lists are known).
In short, if you can get a clear enough picture where we can identify the first upper case letter "after" HZa, we might be able to guess the actual depot. There are a lot of them if you include all the sub-shops and subordinate depots. Probably more than 50, more if you include the specialized shops... this is probably one of the more formal ordnance depots because it is HZa and not HZNa.
