I will be switching to the Hammer 124 grain bullets when I run out of LRX in my 260. For now I am shooting 44.7 gr of Superformance with a CCI 250 in RP Brass at 2865 fps. 2.248 ogive. 3 shots touching appx 0.3" group consistently. This is a Savage Model 11 that I have stiffened the forend and bedded the recoil lug and action. I would highly recommend trying magnum primers with Superformance but you will need to drop charge weight and work back up or do a complete workup again.
Keep your powder and primers and run the Hammer Hunter 124g. Seat them to convenience and you will be done loading inside 25 rounds. If you can't get them to shoot we will by back the rest of the box for the full price of the box.
Steve