Fair enough; if that were the situation I'd totally be on board w/ you.
As was said, I already had this scope and thought I'd use it as a guinea pig.
Also I (sadly) have no where to shoot over 600 yds so the extra room for adjustment wouldn't be an issue. This whole build is a "do it as cheap as I can" and ironically it was my way of not buying another rifle (your Ruger). Instead I'm assembling parts I already had and in this case improving one peice: LR98 Mauset, #3 SS 6.5mm tube chambered to 260 (unsure of twist I got it here for a great price) and dropping it into a stock a buddy gave me.
I will however be buying a fixed fugger if and when I decide to go ahead.
You'll be happy with the M1's.
Just test it thoroughly before stretching it out. Leupold's attention to detail can be pretty schitty at times.
Travis