If that spring is strong enough to set that cap and then fire it on the second shot, I doubt the spring is the problem. On my Wolverine, I noticed that the #11 tries to off set it self too. When I load the #11 with a straight line capper, I really push that cap on hard. When the nipple is clean, it will normally fire. When all else fails, I put the cap on loose, **** the rifle and fire it to set the cap, then I know the next one is going to fire it. I then load the rifle and do what I want to do.