Process of dialing in a barrel though the head stock
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    Default Process of dialing in a barrel though the head stock

    I am trying to dial in a barrel that is supported at the muzzle by a spider in the headstock and the breach sticking out of a 4 jaw chuck. I have rounded brass pivot points on the 4 jaws to allow the barrel to pivot without bending the barrel. I started with centering both ends to as close to zero as I could. I then started to measure two points inside the bore and of course found they were out by .0005. So starts the process of moving back and forth between adjustments at the muzzle's spider and the breach with the 4 jaw.

    Anyone have a strategy to share for how to move back and forth with these two adjustments? I'm driving myself crazy tweaking one end and then the other to find the other point of measurement is now out by .0005.

    One more question. How much barrel stub to you have sticking out of the chuck? I'm thinking the less the better, right?

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    Yes, less length sticking out is better, just leave yourself a little bit so you don't have to move the barrel if you need to push the shoulder back to correct a problem.

    How and where are you measuring the bore of the barrel? I measure at the front of the barrel blank and at the freebore with a long stem indicator. I do not use range rods, I measure directly on the surface of the barrel.

    5 tenths is your total indicated run-out? Your error is half of TIR. Where are you seeing this? At the muzzle I always see a bit more run-out because the barrel is irregular due to lapping. I don't cut the barrel to length until after chambering.

    How much run-out do you have in the bearings of your lathe? When indicating across the jaws, my lathe zeroes 2 tenths different across one pair than the other.

    In cut rifling the cutter advances .0002 inch/revolution. The last groove cut is 2 tenths deeper than the first one. Your indicator will show the rifling get a little deeper with each groove until you get back to the first one, kinda like a snail shell.

    At some point all the noise makes it impossible to indicate better. You'll have to figure it out for your equipment, but it'll drive you a bit nuts in the process.

    There will always be some run-out, even our indicators aren't perfect. Use a floating reamer holder.

    Sent from my Pixel 2 using Tapatalk

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    I am measuring at two points in the breach area using a gritters rod and test indicator. Trying for where the bore will begin, and then 2" further towards the muzzle. Its the dance back and forth between adjusting at the two ends that gets puzzling and frustrating. I tweak one end, it fixes the current measuring point but messes up the other to about the degree I corrected the first. This is my first time trying this setup out. There has got to be a systematic technique to it because I read that as you get better at it, you can set up a barrel much quicker. So what are guys learning as they do it?

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    Learning that it does not matter

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    I always turn two true spots between centers, one on each end and use them to dial the barrel in.

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    I just re-watched the video by "The Viper" on dialing in a barrel on through the headstock, and noticed that he took 40 minutes to dial in the barrel close enough to switch to a 1/10th test indicator. Suddenly I don't feel so bad. He also advised that once you get close, you can simply adjust by tightening the chuck (or fixture in his case), and I found that yes, once you are down to 1/2 thou or less, that generally works.

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    I use Pins in the muzzle and chamber area. In my experience, it doesn’t have to be .000000001” tir to shoot well. I have a test barrel 300rum done in a 3 jaw with around .007” tir that shoots the same as others that were about .0002”. Keep us updated. Fun to watch guys hard work pay off.

    Ps- it won’t take you 40min to dial in a barrel once you’ve done a few. Nothing wrong though with taking your time dialing it in

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    If you don’t have it, buy the Grizzly video with Gordy Gritters demonstrating this technique. It’s very much worth the few bucks and there’s no better way to explain it. I will add that it helps to have one of your points in the bore you’re dialing in to be directly under your contact points of your chuck.

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    Quote Originally Posted by msalm View Post
    If you don’t have it, buy the Grizzly video with Gordy Gritters demonstrating this technique. It’s very much worth the few bucks and there’s no better way to explain it. I will add that it helps to have one of your points in the bore you’re dialing in to be directly under your contact points of your chuck.


    Hey Matt,
    I've tried Gordie's method, but from my machine shop experience, I can't see any advantage and you will end up with a barrel the has the muzzle out of TIR to the throat. A lot has been posted about a barrel bore being curved. The bores can move around from chamber to muzzle, but not in a curve. How about an arc that has a very small amount of twist "helix"?
    What would the difference be if you pinned both ends with Deltronic pins, predrill the chamber, indicate throat, taper bore with a short carbide boring bar, and then chamber with a pusher. We have absolutely no control of what the bore does from the throat to the crown, but we can make the chamber coaxial to the crown.
    Last edited by Butch Lambert; 08-22-2019 at 04:31 PM.

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    Quote Originally Posted by Butch Lambert View Post
    Hey Matt,
    I've tried Gordie's method, but from my machine shop experience, I can't see any advantage and you will end up with a barrel the has the muzzle out of TIR to the throat. A lot has been posted about a barrel bore being curved. The bores can move around from chamber to muzzle, but not in a curve. How about an arc that has a very small amount of twist "helix"?
    What would the difference be if you pinned both ends with Deltronic pins, predrill the chamber, indicate throat, taper bore with a short carbide boring bar, and then chamber with a pusher. We have absolutely no control of what the bore does from the throat to the crown, but we can make the chamber coaxial to the crown.
    I agree with the above comments. Ive done them both ways and dont see any difference on the target. One advantage to putting the crown in line with the throat is if you ever want to set it up in the lathe again for any reason the set up is repeatable and easily checked.

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    As an experienced machinist,not a gunsmith, I can tell you one funny fact! It doesn't matter how much you spent, or the name on that barrel, the hole through it is not true to tenths!!! forget it, it cant be done "at least at the prices of the best barrels available.
    Long gun drilled holes tend to be shaped like an arc, its a problem for tiny long items for medical, as well as large and long items for hydraulics.

    The only solution is a compromise between each end running true, but then, some judgement from perhaps experience with the product, and application could influence that one end should run a little more true then the other.

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    I'm not one against careful work, but you know, once the hammer falls and that barrel sees vibration,torque, and all sorts of pressures, A tenth here or there is just foolery. Heck, have you had a look at a barrel straightening tool?
    Attached Thumbnails Attached Thumbnails barrel_straightening_m1903.jpg  

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    I'm not one against careful work, but you know, once the hammer falls and that barrel sees vibration,torque, and all sorts of pressures, A tenth hear or there is just foolery. Heck, have you had a look at a barrel straightening tool?

    Do you feel there might be "residual stresses" that might play out after the machining operations?

    (I'm not sure why the double post after edit, but just ignore the surplus ;-)

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    Got it as close as I could, then used a Manson floating reamer holder. Taking it to the range tonight and I'll see what the results of my labors are. I've only ever done two barrels in my life. A 308 done between centers, using a homemade floating reamer holder and the trued breach riding on a steady rest, and now a 223 rem through the head stock. I will draw no conclusions about method vs accuracy, as these are two different barrels, and I'm a complete novice. However, if the through the chuck method works as well as the between centers / steady rest method, I'm all for it, as it was simpler for me in some ways, aside from the time for setup.
    Last edited by Grizzlypeg; 08-29-2019 at 11:43 AM.

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    Shoots excellent. I am going to have to up my game to determine just how excellent. It shoots both 69 grain and 75 grain match bullets very well. Under 1/2" 5 shot groups at 100 yards. I screwed up and didn't pack my rear bag, so I couldn't hold it absolutely steady. More testing this weekend to get a better idea of the accuracy. Oddly, when I shot 10 rounds of 55 grain Winchester White Box to adjust the scope, I had 2 failures to fire. None using my hand loads, or the 75 grain target ammo. The primer indents look just as strong on the 2 ftf's as the other rounds. ????

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    I'm envious! hole in ragged hole at 100 is very respectable.

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    I had 2 failures to fire.

    How old is the ammo? Never can tell how it has been stored.

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    The 150 pack of Winchester White Box 55 gr "target" ammo was bought only a couple of years ago. I bought it for something cheap to shoot from my heavy barrel AR. Now that I read the reviews on Cabelas about the ammo, I notice that there are a number of mentions of failure to fire, and all mentioning the 223 version of that ammo. So, I am hoping it is only a problem with this particular ammo. Odd, this isn't a frequent problem with center fire ammo IMO, so it kind of bothers me. I bought a brand new Remington bolt for this 223 build, as the other version of the gun is a 308 I also chambered for it. I can't see how I could have incorrectly reassembled the bolt, but hey its possible. You can only thread the two pieces together so far, then back it off maybe 1/4 turn at most to where the firing pin lines up with the notch in the bolt body.

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    Why not treat the misfires as a learning experience and adjust your firing pin protrusion out a tad to see if the misfires go away.
    Firing pin protrusion is often overlooked so others might have the same problem with that ammo. I would check that out before blaming the ammo.

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    Thanks. That is a subject I know nothing about. I will research that. If you have any resources you can refer me to, that would be appreciated.


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