I'd like to get a feel for just how out-of-whack an action really is
before it is "corrected". This primarily concerns Rem 700s but may
of course apply to other brands.
1.) The barrel face. Is this surface not flat enough and/or not typically
cut at 90 degr to the bore centerline from the factory ?
2.) Barrel threads. If the threads are not rusted/damaged, why would they
need recutting ? Are they also not typically 90 degr to the bore coming
from the factory ?
3.) Bolt lugs. Do the locking ramps wear down enough to need resurfacing ?
I do appreciate the potential benefits of "blueprinting" an engine but I
wonder if all the benefits translate to a rifle action. In a 700 it seems to me
that even a brand new action/bolt assembly is a bit loosy goosy, but I don't
have years of experience here and my suspicions may be unfounded.
Now, when rebarreling, I understand that in order to set headspace,
several dimensions must be juggled and set to work together.
So is the rebarreling scenario primarily when an action would need
any "corrective" machining ?
If you go to the guys Youtube channel, he has a 12 or more part series that shows every step of the process that HE does. I believe that trueing the action is $250 and timing it adds another $175 which includes a new bolt 100% of the time.
This video is the first of the many part series and he will walk step by step through the process and do the machining on camera. If you use a smith like this, you are clearly getting what you pay for. But for every 1 of him there are a couple hundred scam artists.
In my experience not all Rem 700 actions are in need of blueprinting. In the production process, tooling wear and Monday morning causes some 700 actions to be less than good. This shows up mostly as uneven lug fit and non concentric end cut on the action. Threads are not usually a problem as long as they are loose enough to allow the barrel shoulder to mate squarely to the action end.Bolt faces can be off but not a huge amount generally speaking.
There is no easy way that I know of to tell if the action is in need of truing short of taking the existing barrel off. If you have a 700 that no mater how many loads you try, you just can't seem to get good groups with then there may be problems.
These problem actions can and will show very good gains in accuracy with blueprinting. The age old question of "is blueprinting worth it" can only be answered by what the individual wants out of the action. If you are building a bench rest competition rifle then everything you can do to make even minor improvements are helpful. If you are satisfied with 1 MOA hunting accuracy then blueprinting is probably not worth it because most 700 actions will achieve that level.
What I have seen is most newer 700's are really very well made and you won't see a big increase in accuracy with blueprinting. An exception that I worked on was a sendero 25-06 that the owner could not get to shoot no mater how hard he tried so I bought it for a reasonable price as a donor action and found the bolt lugs were not only very uneven but the action lugs were cut on a bevel angle. Don't know how that action passed quality control but when I trued it up it shot very good. Go figure!
If you watch the videos, it clearly shows that nothing is square or straight about any feature. How much out of square is the question... The receiver threads are generally tapered, since Remington cuts them with a tap, vs single point turned on custom actions. Typically also off center.
Remington is flat out making the receivers and bolts using worn out and outdated equipment. They chamber barrels in a vertical mill. No lathe, no dialing in the bore. Nope, clamp it in the fixture and down comes the spindle of the mill... With the cost of modern CNC equipment, they could pitch all of that junk in a heap and be making custom quality receivers much cheaper than the existing guys since Remington has so much volume. I'm pretty sure that all their sniper contracts are re-worked in the back room and they fit aftermarket match barrels or else they would never pass the requirements.
I remember reading a number of years ago that the Marine Corps armorers tear all the 40-X rifles down when they receive them to fix all of the as issued deficiencies. Then the rifles are built back up and issued.
At the time, they were testing a sniper rifle from another manufacturer and were raving about how it was ready to go as received. I don't remember what make and model the rifle was, though.