I have a howa 1500 223 lightweight. It sports the wood stock, was a package deal with the nikko stirling 3x9x42 scope. The first shot is right on, second is away from the group, third is right back to the first shot within a half inch. The same situation with any scope I have put on this gun. The bases and rings are tight, barrel channel sanded out, trigger lightened. Barrel allowed to cool and also shot 3 rounds in rapid succession. Same results. Not bad groups, but second always away from the group. Any ideas?