I currently have a order in with Wilson combat for a 18” SPR 5.56. I was initially going to just use my Nightforce NX8 1-8 scope, but figured this build would benefit from a better scope with more power. I was thinking of going with the Nightforce ATACR 4-16 Scope. My question is i mostly see this scope being used on AR10 or bolt guns. Is this to much of a scope for a 5.56? Plan to use it from 100-600 yards. Another question i had i typically go with Geissele mounts for my optic setups. Would i need the extended version from Geissele? With my 1-8 i used the regular one from geissele which still pushes it a bit forward. I figured with the longer scope i would need the extended or hyper extended version.