What you friend has is a military large ring model 98 Mauser. One of the best actions made - but they require some work to scope properly.

Before you or your friend expend any money on the rifle make certain than the short 22-250 cartridges will feed through the action because feeding can be problematical when the rifle is re-barreled to a cartridge of a different length than original. In the photo the receiver ring has a small cutout that was sometimes done on actions intended for 30-06 or longer cartridges. Checking if the action will feed the intended ammo is of paramount importance. If not; then it needs to go to someone who understands Mauser actions. Mauser feed rail modification is not something all gunsmiths are good at.

1. The clip guide has not been removed from the rear of the receiver so you have to purchase mounts with this in mind rather than use mounts made for commercial Mauser actions such as Mark X.

2. The original safety will not work with most scopes (unless mounted very high) so you will need to replace that also. Several options are available ranging from relatively inexpensive to much more than what he paid for the rifle.

3. It does not appear that the bolt handle has been altered for scope use. This may also be necessary but the photo does not show me enough to be certain.

A further item to consider is the quality of the work to drill and tap the receiver for scope mounts. Are they lined up correctly with the bore? It is not uncommon to encounter holes that are incorrect.

These comments are just a starter. Based on the photos it appears that the rifle needs a visit to a competent Mauser gunsmith.

"It is wise, though, to remember above all else: rifle, caliber, scope, and even bullets notwithstanding, the most important feature of successful big game hunting is to put that bullet in the correct place, the first time!" John Jobson