Tom the irradic sear engagment is what starts the problem , it causes the bolt to "hop" when the sear is dropped and the cocking piece goes over the trigger .
Supposedly when you have a bolt that locks up tight in the bolt race because its been sleeved with the eliptical sleeves also known as Borden Bumps its makes for the most consistant sear engagment possible amking for the most accurate bolt setup , again supposedly
I can tell you that even though you get an over sized bolt fitted to a reamed race way its hard to make a factory accurized gun feel like a custom action , My newest 700 has a tight fitted bolt and I had it coated with Robar's NP-3 process which is kinda like hard crome with teflon in it and the action was coated with KG Gun-Kote its realy slock and tight , the closest I've had to a custom action. but the over all total is higher than what I would pay for a custom.
