I just picked up a Model 10 in .223 off Gunbroker. Serial number puts it in 2003 year of manufacture. I was having about 50% light hits on the primers with failure to fire. All of them fired on the second try. These were all IMI Razor Core ammo. When I switched to hand loads with Wolf primers the problem went away. My Howa 1500 did not have this problem.
So my question is this; is it just that my firing pin spring tension is getting weak after 13 years? Could it be another issue? Is IMI ammo fitted with tough primers? Inquiring minds want to know.