Much of what I have read says to have the bullet sit aout 20K away from the lans and grooves. My local gun dealer says to set a bullet (no primer or powder) long, insert into chamber and try to touch the lans and grooves. Then lower the seating until the bullet barely touches then back off another 20K. I can seat my bullet long 2.52 but when iserted into the chamber it is not long enough to engage the lans. Even long the reciever will accept them. Using Remington 22-250 Model 700 Bullet set at 2.52 Hornady OCL 2.35 Am I not understandig the concept?