The millett rings come w/ the insert to. To be truthful, electrical tape on the rings does the same thing. Like Tim said, they will adjust for windage, but not elevation. Your dealer either is just trying to get you to spend money, or know absolutely zip about scope mounting.
I don't think it's a scope ring issue. All rings for newer remington, savage, and winchester are all the same height. The only brand that I've dealt with that has to have the rings in the right spot is Ruger. I don't foresee him having Ruger rings on his handi.
I understand wanting to boresight a gun, but honestly I got out of that practice a long time ago. The only time a boresight has ever helped me was when I bought one for my Rossi .243 to find out that my scope base was drilled crooked. In that case the Millett windage adjustable rings solved my problem.
@ 25 feet, any scope is going to be high and off a normal sized paper target. @ 100 yards, a rifle that is sighted in at 25 feet is going to shoot way low. Here is what I do when I first mount my scopes. I take a pallet liner 4' x 4' and take it out 50 yards. Put a 1" dot in the center of the cardboard liner. Get your rifle on "paper" this way. If its shooting high or low, left or right the large piece of cardboard will show it. Take a tape meausure w/ you after the 1st three round group and find out how far your off. Then adjust. Once on target, move the cardboard out too 100-200 whatever you want you zero and finalize it.
6 rounds of .223 won't cost much and a big piece of cardboard is free so in the long run I'd recommend trying this before you go and buy a new scope or new rings. It could be that for a 100 yard zero you won't have any issues at all.
