Blueprinting and accuracy improvement - any proof?

[infantrytrophy]

What are you guys thinking??

If some spoilsport performs well-designed experiments to invalidate our tweaking of the ammo, triggers, receivers, bolts, barrels and stocks to try to improve accuracy ...

... then what is left for us to play with? Or to talk about in this forum? What would we do to have fun? ;D

Randy

 

[JLDavid]

Our Moderator did just this very thing with a Stevens in Guns of the Week, the "Poor Man's Hammer."

 

[tome]

as a side note..took a new 700 to a gunsmith/ machinest to be trued.. he's retired and in my club, so he'll do work for me.while he was working i asked him if there a factory rifle made that was true . he told me that the only one he'd seen that could not be improved upon was sako.he said the action was so close, that it was a waste of money trying to improve them

 

[rsilvers]

The factory has fixtures. They clamp the action in, and turn the face. You have to work very hard to make a lathe-turned face not be square. They have a CMM and periodically check them to see if they are matching the drawings. People who do action-tuning services need to justify their existence.

 

[Preacher]

I have never seen a 700 Remington action that had the action turned unless I did it.
The good folks at Remington use a damn chop saw to cut em..
Don't believe me !!!! pull one apart and look at the tool marks...
I've had Remington actions off by as much as .007..............
If the barrel is not square to the receiver your already off to a bad start...

 

[rsilvers]

They are turned and critical areas are ground.

 

[BoydAllen]

If you talk to Fred Moreo, he will tell you that on Savages the threads and lug abutments are usually well aligned to each other, but that the action faces are cut in a separate and much less precise operation. Also the savage bolt head design lets it compensate for minor misalignment. Given all of this, he screws the acton onto a threaded mandrel that is chucked in the lathe till the enc of the mandrel seats on the lug abutments an d then cuts the face to match the threads and seats. Another thing that is different about the Savages is that the whole action is not heat treated so there is much less tendency to have warping along the whole length of the action. Remingtons are another matter, so be careful when you take what someone has told you about his experience with a Remington and make inferences (or design a test) of what you have been told, using a Savage. They are different. What is true for one, may not be for the other.

 

[butchlambert]

I don't believe recutting the threads help unless they are way out. Screw a barrel in to almost lockup and feel how loose it is. The barrel will fit up nicely with a squared face because of the tolerance in the threads. If your bolt is not fitted to the receiver bore, the angled cocking piece will push the upper lug out of alignment.
Butch

 

[Ackman]

I want to see the gunsmith who says "It was nearly dead-nuts on but I still made the skim cuts. Here is the bill."

To find out if it was way off or "nearly dead nuts on" the gunsmith had to do a setup and check. If it's "nearly dead nuts on" but can be a little better, he'll do it. It's as much time to make something dead nuts on from "nearly dead nuts on" as from "not good."

 

[armorpl8]

I want to see the gunsmith who says "It was nearly dead-nuts on but I still made the skim cuts. Here is the bill."

One should ask for a CMM printout before and after the work. That would make a great article - CMM 5 of them and send them out to 5 gunsmiths, and then CMM them when they return. See if they got better or worse.

You do know the cuts are not what takes the most time right? He has indicated the action in the lathe and spent all the time on set up and doesn't make the cuts? At this point 10 minutes of his time is moot...your money has been spent. I want to know who the gunsmith is that will set the machine up and indicate everything proper and then NOT make the cuts....him I want to avoid. It appears you have some axe to grind with gunsmiths or machinists. Do you have any actual machining experience or are you reading books and formulating theories?

 

[rsilvers]

I am not saying that a gunsmith should not charge as much for taking smaller cuts. My point was that I don't believe them when they say that no factory actions are true and I believe they probably are afraid to tell people they spent a lot to make almost no change.

I am looking for proof that 'blueprinting' a typical (non-defective) factory action improves group size and wondering if anyone knows of such a test as I have never run across a before/after test that did not involve a barrel upgrade (which I know can help).

So far I believe lapping the lugs is a good idea both because it makes sense and because it is easy to do.

 

[butchlambert]

Lapping lugs doesn't make sense if you do not have a tight fitting bolt. Read my previous post.
Butch

 

[rsilvers]

When the pressure forces the case against the bolt face, I think it would be good to have both lugs have equal pressure.

 

[butchlambert]

The bullet is already going down the barrel. Your arguments I believe are to get a lot of attention to you. You are asking questions and do not have any answers or do not seem to understand what is going on.
Butch

 

[rsilvers]

Regardless I still would prefer to have the pressure be distributed on both lugs. I don't want a rifle with one effective lug.

 

[armorpl8]

Regardless I still would prefer to have the pressure be distributed on both lugs. I don't want a rifle with one effective lug.

The only way to do that, acheive proper bolt fit, is to have the action blueprinted by a reputable gunsmith. I am not a gunsmith nor a machinist but I have had the rare oppportunity to watch a master gunsmith true a few of my actions. Every cut was documented and written down for future reference. The fact that it makes a difference is, as has been said, well documented. You can't true an action by lapping a bolt if you could there would be no demand for a blueprinting job.....but that may be what you are driving at in the first place, but that dog won't hunt.

 

[NateHaler]

There is lapping the recoil lugs. I think this would help.

How can this help? Some well-respected BR riflesmiths think it's a complete waste of time and money. I'd like to see your theory, for comparison.

 

[BoydAllen]

I've decided to take a new tack. No, it doesn't work. It's a scam. You'd be wasting your money. Prove it, heck the really good stuff, you're lucky to get someone to TELL you. One thing that I have learned of late, some one wants better results,, and then they start to argue with you...it is to smile. You must have us confused with someone who has something to gain by convincing you of something. It's a hobby. Do it any way that you like. Seriously, I wish you nothing but success.

 

[rsilvers]

Lapping the lugs is 10 minutes. One can do it almost as quickly as cleaning the rifle.

I am still to understand how taking 0.004 runout in the receiver threads down to below 0.001 makes the rifle more accurate. That is a very expensive operation and brings the receiver threads out of spec and requires barrels which also have threads that are out of spec.

 

[rsilvers]

The fact that it makes a difference is, as has been said, well documented.

I am seeking such documentation. Please show me a post anywhere on the internet or in any magazine or book which documents that blueprinting a typical (non-defective) action improves accuracy by any amount.

I am not saying it does not - I just want to see the documentation so I can know for sure.