I have an 10 y/o 77/22 I bought new. It has always seemed to have an occasional problem of failing to ignite a shell. However, last week I started shooting again and discovered 50 % or more failure to fires. If I manipulated the bolt vigorously the percentage dropped but still 2 or 3 per a magazine. I tried two different brands of ammo with similar results. I took apart the bolt and cleaned it for the first time. The first 10 rounds shot fine, then it reverted back to light strikes. Any thoughts? Send it back to Ruger? Do you think I can get buy sending the bolt only?