TO add to OOTurok's statement: "Never buy a Trashco (Tasco)", I expand on it this way:
Never buy a scope marked "Made in ____(<---put Asian country here)"
That INCLUDES Nikon. I have seen a brand new, just purchased and mounted, Nikon Buckmaster scope eyepiece lens SHATTER on round #7 after mounting.
Stay FAR AWAY from: Trashco, Simmons, Bushnell, Nikon, Leatherwood, etc. All made in Asian countries. Junk. Garbage. You get what you pay for. Sold at Wal Mart (Simmons, Bushnell, Trashco) Might be good for your $400 "working man" deer rifle sold there as a package "deal" or by itself from the sales rack....but not good for your $2K M1A match rifle.
Leupold is the best US scope made. US Military issue. What I have on numerous rifles of mine from rimfire up to .30-06.
German glass, if you can afford it, is great, too. Schmidt and Bender is USMC issue on the M40A4. Be ready to fork over $3K+ for that. Swarovski, Khales (what I have on my HK-91), Zeiss, etc.
Others like Nightforce. I have never used them.
www.riflescopes.com Shop until you drop!!!
Another piece of advice for avagley: LEAVE and ABANDON the Democommunist People's Republik of Kalifornia (DPRK). Come over to Free America.