Re: M700/clones bolt timing explained
I am talking about a Remington 700 here, but I think it is the same or similar on other rifles. Also, this is just my understanding. Imagine as you are sliding the bolt into the action, the bolt handle will start to break over and close as soon as the lugs on the bolt clear the race ways. The only thing to stop the bolt's foreward movement is when the cam ramp on the rear of the action contacts the bolt handle. I suppose if the handle were way off, either the cartridge in the chamber or the bolt face contacting the barrel would create a stop, but for all practical purposes, what stops the bolt is when the cam ramp contacts the bolt handle. Imagine if the handle contacted this cam ramp before the bolt lugs cleared the races, this would be timed wrong. You basically want very little clearance between when the lugs clear the races and when the handle contacts the cam ramp. Now, the main purpose of the cam ramp is to ease extraction. After a round is fired, the bolt handle is raise, and due to the case holding the chamber, the bolt will continue to rotate without moving rearward until the handle contacts the cam ramp. You want this action to be maximized in order to ease extraction. The earlier that the bolt handle contacts the cam ramp while lifting the bolt on a fired case, the more force that angled ramp will be utilized in extraction. So, basically you want the handle to be as close as possible to the lugs to maximize this, while not putting it too close so as to allow the bolt to not close because the races aren't cleared before contact. I think there is a tolerance here, but the I can't see a reason to not get this as tight as possible.
I wish I had a better description or some pictures. But, hope that helps a little.
Dave
