Rifle Scopes Weaver Tactical Grand Slam?

It's an excellent choice for the money. I have a couple that I use on hunting riflesmthat I also shoot at distance. The only downside is limited internal travel so you will definitely want a 20MOA base.

If you don't need variable magnification and it will be only used as a target rifle I would also suggest the SWFA offerings for the same price, they have nearly 40mils of adjustment and also also made in Japan.
 
It's good for the money. The glass is very clear for $300, but the fixed parallax isn't ideal and the turrets had a mediocre feel. I would take a look at the SS 10x42 and maybe the Burris MTAC 3.5-10x42mm, which has adjustable parallax (objective), surprisingly good glass and a nice glass etched reticle, and can be found under $400 with some searching for deals.
 
I've compared it to a Bushnell fixed 10x side by side. Weight, size, turret feel, and glass quality are nearly identical. It's like upgrading the Bushnell with the ability to go down to 3x. The Weaver lives on my hunting rifle. Very good for the money.