Chucking up a barrel "Part deux"

R

RoyB

Member
With all this talk about how to set up a barrel in a lathe and most of it revolving around a discussion about the straightness of the barrel..............

I offer this......We have all heard about the quite good accuracy of the Savage factory rifles. Some of us have witnessed seemingly amazing accuracy from relatively inexpensive rifles.

Without going into a discussion of toggle headed bolts and barrel nuts being responsible for some of this accuracy, we need to discuss two areas that Savage claims is responsible for the majority of the accuracy.

Button rifles barrels using a very guarded secret button lubricant....And for this discussion, barrel straightening. While attending a tour of the factory, I saw "The Guy"
as he is sometimes refereed to, using an ancient hand wheel press like shotgun builders use to straighten a barrel. Eye sight and a trained hand is all that is used. I was offered an opportunity to see a before and after. I was simply amazed at what you could see with the human eye. I was told that when tested with some type of test instrument, the human eye process was nearly perfect.

Why is Savage the only barrel manufacturer I know of that straightens barrels? Why do they straighten them after contouring and after rifling but before chambering?

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Were the barrels that you saw being straightened sporter or varmint contour? The reason that I ask is that someone who should know told me that the former are straightened, and the latter are not. In the match grade barrel industry, it is my understanding that straightening is generally not done, unless is accompanied by heat stress relief. The thought being that cold straightening without stress relieving induces stress that results in a barrel "walking" as it heats up. If I remember correctly, one renowned barrel maker once stated that the only reason for rejecting a barrel for not being straight enough was if the degree of crookedness was so great as to interfere with the rifling process. He further stated that they had not been able to demonstrate that straighter barrels shot better.
 
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Straight or Bent Barrels

I am not so sure it matters on the Target. I have a Shilen No7 SV profile which was that bad that I couldn't get on paper easily at 200yds, if I screwed it in and we started at this yardage.
It has now won approx 7 HoF points for me in Australia.
It has been rechambered from a HV to a LV and then fluted to Aussie sporter weight. It has been on a Rem700, Panda, Viper and now a BAT.

It still shoots and it has done around 2000 rounds and is 11yrs old

One of my first few barrels and it was a HUMMER!

So I personally wont worry about a bent barrel, if it comes my way

Michael
 
I was reading this thread and a number of thoughts occurred to me when I started asking myself why bother to straighten a barrel?

I came up with two benefits that would be probably be more applicable to sporter barrels, and most applicable to the really slender pencil barrels:
  1. Done right, it should make it easier to get the rifle on paper with the scope closer to center. If the barrel points a couple feet one side or the other, it really messes things up for long range shooting because the line of sight isn't over the top of the bullets path, they converg in the horizontal plane at a given range. Longer or shorter ranges would affect the horizontal zero.
  2. If it results in the bullet taking a straighter path it should improve the accuracy of the rifle and make it easier to find a load for it. Why? Because if the bore forces the bullet to change directions it does so by imparting a side force on the bullet, which imparts an equal and opposite side force on the barrel. Especially in slender sporter barrels this could make a noticable difference in group size, and make it a lot harder to find a load that works in the rifle.
The down side is the potential for thermally induced relaxation of built in stresses caused by the straightening to make the barrel walk more as it heats up. This would seem to be less important than the two positives, at least with sporter barrel hunting rifles, because nearly all shots at game are one shot, maybe two, seldom three, at least for me.

I zero all my sporter barreled hunting rifles by first fouling the barrel with 2 shots. Then I let it sit for an hour or more to get soaked at ambient temperature and take one careful shot. Make the indicated scope adjustment and let it sit for another hour. (Having more than one rifle to shoot, a Nook with a good book to read, or a bunch of other retired OF's to BS with, and sometimes all three, helps to pass the time.) It usually takes two shots to get the zero to about where I want it. Then I test it by shooting three successive cold bore shots. I'm done when the three shots result in the group (usually under an inch) being more or less centered around the desired impact point.

With that done, I'll shoot a couple more to see what happens when it warms up, but that's just for information, I don't make any adjustments based on it.

I see no reason to shoot 5 shot groups when the one and only cold bore shot is the one that counts. If a rifle groups those, it is predictable, and that brings home the meat. If it doesn't, it's the next project or gets a new address.

Fitch
 
Just for the "Paul Harvey for what it's worth department" if I am not mistaken, G.R.Douglas was one of the first barrel makers to realize the benefits of not sraightening rifle barrels. Edwin Flaig told me that Douglas informed him that he made three grades of barrels providing they were within tolerance. Straight barrels which were far and few between,slightly crooked barrels,and barrels that he scrapped.
 
I attended a seminar by John Krieger a while back and someone brought up this question. He stated he does not do it and explained it with a comparison to a copper turbe. When it comes to us, it is usually in a coil and is probably as round as it can get. When you straighten out the coil, the tube does not retain its round profile; same thing happens to a barrel when you straighten it. Go figger.
 
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Straightening something that is coiled and a rifle barrel that is maybe a half thousands out of straight is a big difference.

I never understood why they don't straighten them after the hole is bored and before anything else is done to the barrel.
 
Roy, because Krieger will tell you the exact same thing that I have been saying. Barrels are not "bent", they simply have crooked spots in them that are the product of the deep hole drilling proccess. Bend the barreL so that one of those spots runs true, and another spot doesn't.

Haven't any of you out there ever looked through a barrels ID as it spends in the lathe. Geeze, even Stevie Wonder could actually see what is really going on.........jackie
 
If you guys make it to the Shilen Swap Meet next month let them spin a barrel in their fixture so you can look at the bore. As Jackie says"It is easy to see". It ain't the barrel itself, just the bore that wonders. I think a lot of people think the bad ones are bored in an arc, ain't so.
Butch
 
RoyB said:
Straightening something that is coiled and a rifle barrel that is maybe a half thousands out of straight is a big difference.

I never understood why they don't straighten them after the hole is bored and before anything else is done to the barrel.
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That was an example and how John Krieger put it. DOn't be so damned cynical. If you think about it, the coiled tubing was once round and after coiling it, it is now eliptical. Get it? Sam,e thing can happen to a barrel if you really think about it. Sheesssh

How in the hell, by the way, have you ever measured a barrel a half thousandth out of straight? And have you ever seen one that was that straight. I seriously doubt they exist.l
 
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To paraphrase Einstein: "A barrel should be as straight as possible, but not straighter."
 
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