Pretty obvious it was meant to be attached using a sloping mount. You could probably get good $$ from a collector.
If the optics are good and you want to keep it, then there may be an alternative. Mount it parallel to the bore. Sight it in using the center reticle (looks to be 12?) for, say, 250 yds. That will give you at least 300 for hunting purposes with a flat shooting round.
For longer ranges: Zero out the dial when sighted for 250. Print out a trajectory table for your load in MOA or however the turret is marked, and crank it based upon your rangefinder. Otherwise, there was a thread here about printing your own custom dial strip to wrap around the turret. Use 250 as the starting point and mark it for 275, 300, etc.
If the optics are good and you want to keep it, then there may be an alternative. Mount it parallel to the bore. Sight it in using the center reticle (looks to be 12?) for, say, 250 yds. That will give you at least 300 for hunting purposes with a flat shooting round.
For longer ranges: Zero out the dial when sighted for 250. Print out a trajectory table for your load in MOA or however the turret is marked, and crank it based upon your rangefinder. Otherwise, there was a thread here about printing your own custom dial strip to wrap around the turret. Use 250 as the starting point and mark it for 275, 300, etc.