My method of working between centers is the best I can do since I cannot run the barrel through the headstock. The tenon and the barrel beyond the tenon are worked with reference to the center, then on the steadyrest which was set and run smoothly with the barrel on centers. The reamer seeks the center of rotation. I do not see a better way using my lathe (not a gunsmith lathe with a large headstock bore). I make ACCURATE barrels.
Barrel Blank Curve
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I chamber through the bore on my lathe and dial in on the bore. I place the curve up, as most do, with a test indicator at the muzzle. I then I use an indicator on the OD of the barrel breach to mark as fine a line as I can with a small sharpie. I use a similar method on the action to find TDC to help line then up.
I think another question to add to the original question is how short of lining up the marks do you set the tenon shoulder in the lathe prior to taking it and torqueing to spec? Part b) same question with or without the use of anti-seize. Maybe part c) how much anti-seize to use?
I think another question to add to the original question is how short of lining up the marks do you set the tenon shoulder in the lathe prior to taking it and torqueing to spec? Part b) same question with or without the use of anti-seize. Maybe part c) how much anti-seize to use?
Typically I allow for about .002 "crush"- which allows for around 5-10 degrees rotation on a 16-20 tpi tenon.
Making sure your barrel shoulder and receiver ring are perfectly faced/perpendicular to the tenon mimimizes this.
This should end up at go + .001-.0005. Obviously a coarser pitch will affect headspace to a greater extent for any given amount of rotation.
I've never "not" used (nickel) anti-seize on final assembly, and if I've got the action on-hand the threads are always lubed with machine oil when test-fitting the receiver lest the threads gall during that process. You never want to try to fit threads dry.
Hard to quantify "how much"- not sparingly, but careful not to glom it on the threads- you don't want any to push out ahead of them onto the shoulders.
JMOYMMV.
Ok, the barrels are not perfectly (tough absolute word) straight. If the bullet leaves the barrel just a bit off of absolutely aligned (hard to do with a curved barrel) with the bore and you zero the rifle with the barrel pointing any old direction from the curve. IF you zero it, that accounts for the curve. Unless some force acts on the bullet after it leaves the barrel my mind says the curve does not matter at all. Its path is not effected after it leaves the barrel and if it hits the bullseye all is well. More of my 19th century thinking I am sure.
bigngreen
Well-Known Member
My barrels turn the width of the base screw hole, a large precision cut thread does not move much, I don't see any change in the chamber length when tightening, what I set it to in the lathe it toques to.
Thanks for all the input. I pretty much follow all the same steps and info. John Hinnant's book talks about an amount of rotation to tighten. On the last barrel I did, I took some measurements, just for my records. I use a barrel holding jig instead of jaws and I only hand fit the receiver in the lathe. When torquing to 100 ft lbs with a very thin layer of nickel based thread locker, I got an arc measurement of .150". headspace reduced just less than 0.001". This is very consistent with the tools and methods of installation that I use.
I agree that I wouldn't want to time a barrel in any direction but vertical. Honestly, I don't want to bother with timing a barrel. I have tried a few barrels by dailing in the muzzel and the throat location and have had just as good accuracy. It seems to me that this last method is the easiest way to do prefits. I'm not sure one could time a barrel to an action without the action in hand. Prefits are becoming more popular.
I agree that I wouldn't want to time a barrel in any direction but vertical. Honestly, I don't want to bother with timing a barrel. I have tried a few barrels by dailing in the muzzel and the throat location and have had just as good accuracy. It seems to me that this last method is the easiest way to do prefits. I'm not sure one could time a barrel to an action without the action in hand. Prefits are becoming more popular.
I use barrel nuts on all of my rifles (Remington 700, Ruger American, AR-15, Savage) and change barrels often: takes about 15 minutes if I have to remove the scope. I don't know how timing barrels would fit in my methods. Many years ago in the '50's onTV (maybe it was Industry on Parade), Remington had a man who straightened barrels by shining a light through the bore and bending the barrel with a shop fixture (turn a heavy hand wheel to bend). It was part of normal production at Remington I believe. All done by a craftsman by eye: before lasers and such, no measuring, just eyeball.
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I time the muzzle up between setting final shoulder depth on the action and chambering. A few more steps based on how you chamber between there, but that's the basics.
