I picked up a weaver 44/40 in 4-12x44 the other day at a pretty good price for my 243. It's new but outta the box so no paperwork included. It looks like it has pull up resetable turrets but I can't figure out how they work. I tried pulling up on the outer part of the turret but it won't budge. Anybody have one of these and know how it works? Thanks