Accurate Shooter Article: Test of Factory action before and after "trueing"

[Alex Wheeler]

Max pressure happens once the bullet is only a couple inches into the barrel, at this point both lugs are seated. The difference in a tight fitting bolt is that its top lug is unseated less. But I would bet they both seat at about the same time relative to bullet travel.

 

[Mozella]

Well, unfortunately I have done this test. ........ snip............ I took it to the range and it is 1/2" or better more times than not (if the nut behind the bolt does his job) and a bad group is 3/4". ........ snip...............

With respect, what you did was not actually test. Yes, it's an anecdote and it's nice that your rifle shoots OK now, but your experience doesn't answer the OP's question.

I have achieved the precision you mention numerous times starting with an inexpensive Savage rifle or action, screwing on a 4 or 5 hundred dollar barrel, bedding it in an inexpensive Boyd's stock, and working up some careful hand loads. No truing, no fancy machining, and no need for a gunsmith. Any DIY shooter can make a nice shooting Savage in his/her garage without any outside help. I think you could say something similar for many other brands of factory rifles.

As you explain in your complete post, you had a pretty bad rifle which, after lots of work, plenty of frustration, and a considerable sum of money, you finally got to shoot acceptably well. Congratulations, but truth be told you didn't have a good rifle which turned into a great rifle simply by truing the action. That's the hypothesis on which this thread is based. Perhaps I'm wrong, but I assume the OP is talking about a properly functioning rifle to begin with. As I understand the question, is truing the action of a descent rifle going to show significant and measurable improvement in precision at the target or is it mainly a process which makes the rifle cycle better/faster?

I'm not sure what was wrong with your rifle to start with, but I think you would agree that the initial performance was not what one would expect from a half descent factory rifle. That is evident from your long and frustrating quest to correct the unknown problem. In other words, something was wrong with it and perhaps truing the action was the step that set things right. But the question at hand is, as far as I can tell, about any potential improvement associated with truing up a good rifle, not repairing a defective one.

 

[johnfred1965]

Well, I've done it. I bought a Remington cheapo in 25/06 because of the price only. I don't care for the caliber. It shot 2"-3" groups of 3 shots with factory ammo. I put a 36X scope on it and used windflags. I said this is the chance to see what works. Since I am trigger sensitive I put a crisp Shilen trigger on it. Couldn't tell much difference. Bought a name brand custom stock and bedded it. Groups went to 1.5"-2.5" with the same ammo. Next step was to take a cleanup cut on the face of the receiver, locking lug abutments, and single point the receiver threads. This being a newer CNC receiver it was so close that it took little. I barely touched the nose of the bolt and the back of the locking lugs. If you write all your cuts down you do not need to set the barrel back. I cleaned up the recoil lug on my surface grinder. Yes, I reinstalled the factory barrel as practically nothing was removed from the threads. ABSOLUTELY no change in accuracy. I chambered a barrel from a Wisc. barrel company and best it would do was 1.25"-2.25" with the same factory ammo. It seems that reloads helped marginally, but not enough to crow about.
This is just my experience on a one time deal. Most all factory rifles will kill an animal out of the box. Was it worth it, well somebody got it cheap.

Hope this isn't an advertisement for your acurizing services!

 

[johnfred1965]

But the question at hand is, as far as I can tell, about any potential improvement associated with truing up a good rifle, not repairing a defective one.

Why would you true up a good rifle? Of course the truing process is to repair defects. Like when remington cuts the action threads cock-eyed to the bore of the action. To blueprint or true an action, you are talking about getting all your surfaces and axies within a couple tenths. I don't know where it really starts throwing your bullets around, but I'd say if you only shave 1-2 thousands off the lugs or face, and the threads are relatively straight, a good barrel is all you need for rifles up to varmint types where you might want to hit a 1.5 inch head at 400 yards. If you are a benchrester, looking for actual one hole groups, you had better clean up that 1-2 thou, or as others have said, buy a BAT or "roll the dice"

 

[johnfred1965]

If any of my comments have caused offense, none was meant. I sometime use sarcasm to try and make a point. (well actually most of the time)

 

[Mozella]

Why would you true up a good rifle? Of course the truing process is to repair defects. ..... snip...........

You would true up a good rifle in an attempt to make it a great rifle. I don't know how many of the people I compete against in 600yd F-class and 600yd BR have had their action trued, but I know many of them have.

At least one local gun builder trues ALL the rifles he sells. The idea is, of course, to give it the best possible chance to win. Is it worth it? I can't say for sure, but I do know that most people I compete with did not have their rifle trued because they found a defect. They had it done before the rifle ever fired a shot.

 

[johnfred1965]

You would true up a good rifle in an attempt to make it a great rifle. I don't know how many of the people I compete against in 600yd F-class and 600yd BR have had their action trued, but I know many of them have.

At least one local gun builder trues ALL the rifles he sells. The idea is, of course, to give it the best possible chance to win. Is it worth it? I can't say for sure, but I do know that most people I compete with did not have their rifle trued because they found a defect. They had it done before the rifle ever fired a shot.

I think we are saying the same thing just a little differently. I had a varmint rifle built,(All I started with was a m7 action, not a whole rifle) Since I didn't want to take the chance of putting a good bartlein barrel on a crooked rem action, I had it trued. Not a benchrest gun, but I avoided the chance the workers at Rem were asleep when they built that action.

 

[rogn]

Im jumping ahead here but wouldnt just setting up a Remage basically out of the box then following this with a blueprinting achieve the same thing with a lot of the fuss needed to do the stock Remi. My thoughts on the threads and thread diameter would certainly be a variable. But wouldnt this be reflected by the Remage collection of tolerances . I would suppose may of the barrel tenons used in this "system" could vary by quite a bit. ???

 

[BoydAllen]

One more thing, there is some thought that vibration from the action that makes it to the muzzle before the bullet does has an effect on accuracy. Beyond the issue of when lugs are seated, assuming that the action allows them to be, which in the case of some factory actions is not the case, there is the matter of how much vibration is created by their coming into contact during firing. One time I had a conversation with a fellow with impeccable credentials about whether identical benchrest actions that he owned showed differences in accuracy with the same barrel. He told me that they do, and that the difference travels with the striker assembly. You might want to give that some thought. Ultimately this all comes down to vibration, how it is created, how it is controlled, how consistent it is from shot to shot, and its degree of magnitude. Even if we have a budget to do testing, the tests are only as good as our understanding of the mechanisms that we are testing. If we misunderstand what makes things happen, we can come to erroneous conclusions as to cause and effect. Many times we have found that if closer fit is better, that beyond a certain point it is not, that if some is in fact good, that more may not be better. It may in fact be worse. Currently I am waiting for a barrel that will be fitted to an action that I have two bolt bodies for. One has "normal" clearance to the action, and the other is as tight as it can be and still have the action function without binding. The design has separate bolt heads. (No, it is not a Savage.) It will be interesting to see if there is a difference in accuracy when the bolt bodies are interchanged. I plan on doing this at the range. It may be interesting. Of course my first task will be to get the rifle and load sorted. I am tempted to start with the looser bolt since all of my previous experience has been with that sort of fit.

 

[Alex Wheeler]

Here is a real simple way for a guy to test this. Cut a piece of .002" shim stock and epoxy it to the back of the bottom lug. You may have to bump your cases another.002, but this will allow you to shoot a couple of groups with only one lug seating. Then you can just remove the shim and clean off any epoxy, and your back to normal.

 

[mram10]

I think the test is fairly simple. Wouldn’t be expensive. I will volunteer a stock rem 700 long range in 300rum. I will shoot different loads and post the targets. Someone with a lathe can true the action and I’ll go shoot again. Easy. I’ll volunteer the rifle, targets, ammo and time.

 

[AckleymanII]

Seriously??? Let me give you an example. A friend trued up the face of his Remington short action using a proper tight fitting mandrel, between centers. In spite of this he continued to have accuracy issues with several barrels. Later a friend turned a close fitting false tenon with shoulder and while it was still in the chuck tightened the action on it by hand. When the face of the action was touching the false tennon's shoulder on one side, there was a gap on the other, and the face of the action was square to its bore. It turned out that the action threads were off center and cocked so much that the threads had to be opened up .025 to get them to clean up. This is the sort of thing that gunsmiths who true actions have to deal with. BTW after the action's threads were recut the accuracy problems went away.

This type of issue will happen with a few actions, and you chase your tail forever when it does happen.

 

[chop house]

Here is a real simple way for a guy to test this. Cut a piece of .002" shim stock and epoxy it to the back of the bottom lug. You may have to bump your cases another.002, but this will allow you to shoot a couple of groups with only one lug seating. Then you can just remove the shim and clean off any epoxy, and your back to normal.

brilliant! then, once you have results on a 700, repeat on a savage

 

[BoydAllen]

There is one factory action where you will never have to worry about whether both lugs are making contact, the 340 Savage. It only has one lug. The "bedding system is also somewhat unique, a single screw into the edge of a trapped recoil lug and a barrel band, tensioned with a machine screw.

 

[chop house]

the 340 Savage. It only has one lug

years upon years ago i recall conversations about the weatherby (9 is it?) lug system and a materials/mechanical guy said that really only one at a time takes the stress, infering that they could in fact fail in a serial fashion.

is the weatherby system accurate, or simply over complicated?

 

[IdahoCTD]

I think the test is fairly simple. Wouldn’t be expensive. I will volunteer a stock rem 700 long range in 300rum. I will shoot different loads and post the targets. Someone with a lathe can true the action and I’ll go shoot again. Easy. I’ll volunteer the rifle, targets, ammo and time.

It won't work like that. You have to approach it backwards or you have to cut the threads and part of the chamber off and start over. That's not going to happen on a factory Remington barrel. You could cut everything but the threads but that isn't really a complete test. To reuse the existing chamber, and not change things, you'd have to start with oversized threads and make them smaller to fit a stock action. That means a aftermarket barrel. A 300RUM isn't the best caliber to test accuracy either.

 

[mram10]

It won't work like that. You have to approach it backwards or you have to cut the threads and part of the chamber off and start over. That's not going to happen on a factory Remington barrel. You could cut everything but the threads but that isn't really a complete test. To reuse the existing chamber, and not change things, you'd have to start with oversized threads and make them smaller to fit a stock action. That means a aftermarket barrel. A 300RUM isn't the best caliber to test accuracy either.

I have extra barrels we can try. 300 rum is fine to test accuracy. My edge was my most accurate rifle for a long time. You know numerous guys that shoot big calibers accurately Nathan.

 

[okie]

This was NOT back in the day and it was not sleeved. Good shooting....James

This was NOT back in the day and it was not sleeved. Good shooting....James

yeah, I have not seen a sleeved one in a while...