Re: To blue print or not to blue print a rem 700 a
I've read this thread and looked at the photos of groups. Chucknelson, out standing groups and nice rifle. I wouldn’t touch it either.
I can tell you this with all certainty, every Remington 700 receiver I've worked on where the machined surfaces and raceways are in question, with out fail, have not been concentric, coaxial or perpendicular to anything.
First let me say this, there has to be a standard for checking the previous machining, whether it was performed by the factory or another smith. The bolt raceway seems to be the standard location in which all other machining is compared.
Now, in a Remington 700, the bolt raceway is no where close to being true and concentric with the center line of the rifle bore and or the receiver body. When measured, there is a difference in diameter between the raceway located in the front receiver ring and rear receiver ring by as much as .002". The standard is to use a tight fitting mandrel inserted in the bolt raceway but, if there's a difference of .0005" to .002" between the front and rear receiver rings, you'll never get the dial in dead nuts. For this reason, on my personal rifles and those customers that wish to have the same, I ream the bolt raceway to .705” and install a .703” PTG after market bolt body and handle. The fit and function is flawless. After reaming the raceway, the actual reamer pilot is used to dial in the receiver
The method I use is what I feel to be the best method based on the variables I have no control over. I start by inserting the tightest bushings that will fit into the receiver raceway, front and rear. The bushings are those that are sold by PTG. It's not uncommon to use bushings that have as much as .002" difference between them. The receiver I checked just last night took a .703" in the rear and a .7045" in the front.
I next insert a .500" diameter precision ground mandrel through the bushings and insert the entire package into a truing fixture I've made. The truing fixture has an OD of 2.5" and is 3" long. It has an ID of 1.500" that will accommodate an aluminum sleeve, slip fit, with an ID of 1.37"ish, just a slip fit over a 700 receiver. A total of eight 5/16 x 24 screws act as in board and out board spiders and are what adjust the receiver for dial in.
I indicate the receiver in by its raceway using the bushings and precision ground mandrel to .0002" or less. At this point truing cuts can be made and it's also at this point where you can tell how much the receiver is out. To date, all receiver faces, bolt lug abutments and receiver threads have failed to be perpendicular and or concentric to the raceway.
When truing cuts are made to the receiver face, bolt lug abutments and receiver threads one can see just how far out they really are. The bolt lug abutments are usually so far out that there has to be a measurable amount of receiver bolt deflection when the bolt is closed. The deflection will be either up or down and slightly off to one side. What does this do to your chambered round in relation to the chamber / lead / throat?
The receiver face is never perpendicular to the bolt raceway causing the barrel to look off in its own direction, yet another list of problems not to mention a recoil lug that hasn’t been ground parallel. Ever have trouble getting a particular rifle to zero or run out of horizontal adjustment in your scope?
The bolts are more times than not fairly straight but a clean up is in order. The clean up is made so the rear of the locking lugs, bolt face, bolt nose and locking lugs front are all perpendicular to the bolt raceway. The cuts made to the bolt nose and locking lug front are just cosmetic, nothing more.
In short, if your spending money on a custom barrel and its installation and pillar bedding, true the receiver. If it's a factory Remington 700, it's not even close as it comes from the factory. If someone is saying "its wasted money and useless" I want them to be at one of the matches I shoot in.