Air rifle optics - Hawke Sport Optics Vantage 3-9x40mm Rifle Scope 1in Tube Second Focal Plane

This scope is as advertised. The problem is that air rifle scopes may not withstand the shock of the most powerful spring powered air rifles. I am going to have to move this scope to a lower powered rifle to evaluate it's ability to maintain zero. The problem may be the rifle, it's power, or the scope, but I haven't gotten consistent groups. I have used all the zeroing protocols of good range practices to little success. Shots vary by 1 to 1 1/2 inch at 25 yards. This may be a fine scope for the money, I just can't be sure yet.