Weird! I ran a couple of magazines of the Fiocchi 90 grain XTP HP Bullets and had no problems at all. I also shot a couple of magazines of Speer Gold Dot 90 Gr. GDHP bullets and several magazines of Winchester 95 gr FMJ with no problems at all.I then tried to run a couple magazines of the Fiocchi 90 grain JHP thru the gun and they jam up in the magazine and will not feed
Maybe you should contact Ruger?
I just ordered a second magazine (being sent to Idaho since I can't use the LCP in Kalifornia). I'll check it out when I'm in Idaho at Thanksgiving. It could be magazine specific. Have you tried it in a second magazine?