Re: rem 700 action truing method??
300,
Robert, yer a smert cookie!
As for clearances:
This may be a little off track, but hopefully it helps to support the conversation.
In 20+ years of being around this stuff there's only one bolt action rifle that I've encountered that essentially has zero play between the bolt and the receiver. The Grunig and Elmiger FT300 CISM rifle. (I'm a US service center and non stocking dealer for G/E btw)
That being said the action that comes to mind that offers a complete and total solution to these kinds of questions is the Miller Arms line of falling blocks designed by Cyle Miller in St. Onge, SD. Pretty much THE rifle to have if your a Schutzen addict.
Now, if that is indeed the case then why isn't everyone using guns along these lines for extreme accuracy? The bench rest boys are about as obsessive as it gets.
The truth is neither of these two rifles shoot any better or any worse than a bolt gun with a good barrel and a sharp nut on the trigger.
I don't mean to undermine the importance of tolerances. I take a great deal of time when blueprinting an action to ensure the numbers are right when its all done. However my motives are a bit different and I'll use a simple comparison to explain why.
Take a stock camaro and a stock "supercar" of your choice.
The camaro is manufactured as fast as GM can produce it. It starts, goes reasonably fast, stops, and turns better than most other cars.
It's still a camaro.
Now the supercar. It's hand fitted. Everything is touched, fluffed, polished, rubbed on, and loved from the headlights to the screws that hold the rear license plate.
There does exist a percentage of folks who want that kind of individual attention when they fork over their 40 hours a week.
That is part of why I blueprint an action.
The other aspect that's often underscored are the threads. Concentric threads are one thing. What I am really interested in is a threaded receiver ring that has a bright, shiny, cleanly machined thread.
When I machine my tennons they too are bright, shiny, and free of <span style="font-style: italic">surface inclusions.</span>
The reason is when you get a barreled action from me you will immediately know something is different if you take the barrel off. The thread fit mimics the feel of a thimble on a micrometer. I obsess over it.
We can sit for hours and debate a hundred different subjects when it comes to gun making. An indisputable fact however is that ALL the energy a cartridge generates has to be managed in some way at the threaded union between action and receiver.
Take the worlds strongest man and have him hold a barrel with all his might. Now get a preschooler and have her grab the muzzle. With one finger that little kid will steer that barrel wherever she wants.
The fact that an action does as good a job as it does amazes me. In my mind it's vital to have a thread fit with as close to zero tolerance as possible. The only way to mitigate a seizure between tennon/receiver is to make improvements upon the surface finish so that inclusions aren't snagged and peeled-which consequently contaminates the threads between the flanks and causes galling/seizure.
FWIW I don't use an anti-seize compound during assembly either.
What this dissertation is trying to say is I have a very difficult time accepting that a tap will get me what I deem as important.
I also don't buy the notion that a tap centering on a mandrel will cut a path independent of what is already there. The tap wants to follow the hole. There's a bunch of tool engagement so the part will win and the tool will take the path of least resistance.
If it will then by the same argument a guy should be able to buy a die and stuff a mandrel in the bore and cut his barrel tennon the same way.
I have two CNC slant bed turning centers here. Both are several thousands of pounds in weight. If I were to rigidly mount a tap in my turret and then intentionally bump the X offset by say .005" I know beyond the shadow of a doubt that the tap would not cut a concentric thread. It would end up having some sort of funky taper.
This is why I don't buy the mandrel trick.
That being said I'd be willing to speculate that if we took 10 actions single pointed and 10 cut with a tap we'd see no change in accuracy if all other things were equal. (barrels, cartridges, bedding, etc)
Improve the quality of the thread fit however and I do think (and experience has taught me this to be true) accuracy will improve. Leaps and bounds? No, but it is there and it's enough to justify me devoting the programming time and effort to make sure I get it.
In my "6mm Remix" thread on here I made the decision to ditch the factory bolt that another smith ruined. We got a new PTG bolt instead and it was fitted to a minimal tolerance. (monkey see monkey do) I did not touch the barrel other than to neatly engrave the caliber on the side. No other work was done.
I've bedded the stock and put my "fluff" on things, but the action is an untouched 700. Both bolts headspace (thank god!) which presents me with a unique opportunity. The only difference with the PTG bolt is I have one of my fire control setups in it. I can't say conclusively but the feedback I'm getting from the customers that have them are that they do see a small improvement when they switch over to it. It may be them justifying the expense, but it's been overwhelmingly positive so I like to think it's not just "fluff".
The customer and I are going to shoot the dickens out of this thing with both bolts. One is the supercar bolt and the other a rusted out trailer park camaro.
It'll be interesting the see the difference on paper.
Hope this helps.
C