The top performing competition springers are all under or side lever models, which should tell us something: Unless you spend big money (>several hundreds) on a break barrel springer, you'll never get consistent lock-up, and even pricey ones loosen up. Therefore, a scope on the receiver is rarely going to remain in consistent alignment with the bore. Hold can help some, but the best solution is to ditch the receiver mounted scope and shoot irons, assuming of course that the irons are on the barrel. At effective air gun ranges, even people with lousy vision should be able to shoot irons, and the practice will make you a better shooter overall. If the scope is a cheapo, then you may also be suffering from moving internals - springers are notoriously hard on scopes.
