Seems like I get zero set before a match, and then a couple days later, at the match, I need 10-20 sight-in shots to get rezeroed. And often I wind up right back at my original zero. Do I need to heat up the lube? I don't clean it after sighting in. It seems to be OK after the first stage, even though there is plenty of time for the barrel and wax to cool down, between stages.