My friend called last night and said he mounted a 6.5-20 Leupold with Target knob on his STW and he cant get enough height out of it, he is hitting the target at 100 yards about 4 inches low and he is topped out. I think he has the rings or something on backwards. What are your thoughts? I also told him he will need a rail on for long range shooting.
definitely a vertical alignment issue... I've had to shim a few rifles in the rear because the scope wouldn't make zero topped out. I did one for a co worker last November. Offset rings, a moa base going the correct direction, or a simple metal shim are the likely answers.
You don't need a rail, although it makes it easier. You can shim the rear mount about 10 thousanths of an inch to 15 thousanths of an inch to get on target. I went through this with Nikon, and found better information on the web than Nikon could offer. If you are using standard mounts, and a long range scope, you will probably need to shim the rear mount about 10-15 thousanths of an inch.
Rail mounts are easier because mounts with the 10-15 thousanths of an inch cant are readily available.
My rifle was hitting 6 inches low with the elevation adjusted as high as it would go. After shimming the rear mount 10 thousanths of an inch I could hit dead center at 100 yards with the elevation adjustments approximately in the ceter of the adjustment range. Now I am getting 3/8" - 3 shot groups at 100 yards.