Just got the new gunsite 450 Bushmaster and love it with the exception od the mag. It wouldnt feed anything other than gummytips. Since its a .452 bullet that leaves out most of the reloading options. Really its a bad design and honestly negligent of Ruger. My mag would feed the round forward until the last past of feed lips then nosedive down. At first the case mounth would then grab the forward mag edge. I clearanced thst and then the HPs and TMJ bullets would feed below the feed ramp. Here is the negligent part: bullets would get smashed into the case. But being a case mouth headspace round they will fire. Pressure spikes could easily blow a rifle up in this condition.
So next I polished the feed ramp like a 1911 and this helped a lot! All but the biggest HPs would feed 3/4 rounds out of a mag. Still not good but better. The feed ramp angle on the GSR is steep. So I went to work on thr mag instead of clearwncing the ramp. The feed lip is stepped slightly in the front but not enough. I added a brass shim to tur forward edge now it feeds like a champ.
I have pics if anybody wants them. Took me 30 min and about $13.
Im a Ruger fan but this mag was a magor disapointment. Ruger is sending me another but the design has issues. In a .308 im sure its fine. The step from bullet to case neck in a 308 has a 1/4” more step then a straight .450 nose.