The S&K mount for milsurp rifles which replaces the rear sight.....and thus the scope is mounted forward of the receiver (on the barrel) is fine. They are good mounts and will work with no problems. That is, as long as you can use/ get used to the forward scope ("scout rifle") configuration. I happen to like that setup, myself. The rear-sight type mounts do end up placing the scope rather HIGH, however. So, it is often necessary to add a cheek riser on the stock, to have proper alignment with the scope. But, overall, this can be made to work well - IF you like or can tolerate a long eye relief scope setup. Some hate this arrangement.
The other type of S&K scope mount for milsurp rifles, which sort of clamps around the receiver (and uses a conventional scope mounted over the receiver) .....is terrible. At least, for the Mausers it is terrible. Poor idea and just does NOT work well. I would avoid that one at all costs.
The best option, for scope use on a milsurp rifle, as I'm sure you already understand, is to drill and tap and place conventional mounts on the receiver. This can have it's own problems (bolt handle clearance, for example). As well, it will destroy the originality of the rifle - and make it NON-collectible.
IMO, the best option overall for milsurp rifles is to leave them alone.....and learn to use the iron sights. The irons can often be improved, by using slightly different types or slightly modifying them, without butchering the rifle. If one wishes to make a "sporter" out of a milsurp, IMO, it is best to go all out and do the complete job - or not do it at all. Milsurps with original stocks and poorly added scopes, etc. don't make for great all around rifles. On the other hand, one which has been properly "sportered" (a quality job, with all the details addressed)....can be a great all around rifle.
