I'm looking at getting a scope for my P15 as the current one I'm using is not much use as for some reason the reticle doesn't stay in place after zeroing. I've seen a Nikko Stirling Mountmaster 3-9x50 AO Rifle Scope online which has a rrp of £81.99 and is being sold for £49.00 and is brand new. I've dealt with the company before and they are very reputable but I'm wondering if the scope is half decent of is it worth me paying a bit more for a Hawke scope?