1st time Bartlein barrel

Discussion in 'Gunsmithing' started by specweldtom, May 27, 2014.

  1. specweldtom

    specweldtom Well-Known Member

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    Just installed a Bartlein barrel. Only one I've done. It is the straightest barrel I've ever spun in my lathe. T.I.R. is < .0002" at the breech, .0000" at the muzzle, and < .001" in the middle of the 27" blank. It also cut and threaded very smoothly.

    If it shoots like I think it will, it won't be my last one. I'm impressed!

    Tom
     
  2. JBRC

    JBRC Member

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    How did you indicate the middle of a 27" barrel?
     

  3. EddieHarren

    EddieHarren Well-Known Member

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    I would also be interested in finding out.
     
  4. IdahoCTD

    IdahoCTD Well-Known Member

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    I've used quite a few and they have been the straightest barrels I have used also. I haven't had a bad one yet. I guess that's why I have 6 or so more in the safe for when I get off my butt to build them.
     
  5. specweldtom

    specweldtom Well-Known Member

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    Not rocket science or I couldn't do it. I set the barrel up in the lathe chuck on one end and the live center on the other end. My 3 jaw chuck is corrected to .0003" on a lathe alignment bar, so I rarely use the 4 jaw.

    I indicate the muzzle end on the live center (BesTest Last Word), rolling the barrel away from me by hand. Then indicate the middle of the barrel. I record the t.i.r.'s and then turn the barrel around and put the muzzle end in the chuck and indicate the breech end on the live center. Move to the middle again and indicate it again. If there is any difference at the middle, I just average the readings. Like I said, not rocket science and not perfect, but only takes about 10 minutes and it tells me how straight the O.D. is and how concentric to the bore it is at the ends. Over the space of 10-11 yrs I have done a total of about a dozen Liljas, Harts, Shilens, 1 Krieger, 1 Brux, 1 Lawton, and this Bartlein. Also some factory take-offs out of curiosity.

    I have never had a perfectly straight or true barrel.

    If the breech end has .001" or more runout, I turn it true while it's on the live center. The muzzle end is a little more trouble. I set it up on the live center and turn it true about 1/2" in front of where the crown will be, then use that to indicate in the muzzle threading or crowning setup, then part it off. Like I said, more trouble, particularly when I have to use the steadyrest and make an interim setup. Depends on how much longer the blank is than the finished length. The closer they are, the easier the setup.

    The Liljas have averaged being the straightest, the factory barrels the worst. One ran out .055" in the middle. Tomato stake.

    The worst runout on a premium barrel was .0075" in the middle. The finished rifle (.338 Excalibur) hammered at 1K, so that amount of runout didn't appear to hurt it.

    I don't have a set of range rods, so I fell back on this system.

    Sorry about getting long-winded, but wasn't real sure I understood the question, so went into considerable detail.

    Poorboy process, not for benchrest but works well for me. A couple of them shoot in the teens, a few in the 20's, most are sub 1/2 m.o.a., a couple just sub m.o.a.

    Good shooting, Tom
     
  6. SidecarFlip

    SidecarFlip Well-Known Member

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    Pierce is building me a Bartlien barreled 308 light contour right now. Good to know I have founded confidence in Bartlien.
     
  7. Hired Gun

    Hired Gun Well-Known Member

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    Barrels are contoured based off the 60 degree center drill into the ends of the barrel. The end of the bore is indicated and the center drill is run based on that. They ought to run dead true on the ends from the bore. I can't imagine how one could be off center. I have watched them profile barrels. It is done at 4500 to 5000 rpm. I would think .0075" run out in the middle would be shaking the house down.

    I only use Bartlein and Krieger if I'm asked my preference. I have found Bartlein to be consistently straighter than ANY other barrels. I can't really say they shoot measurably better than any others though when I'm putting my best foot forward it's with a Bartlein.
     
  8. EddieHarren

    EddieHarren Well-Known Member

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    Pardon me, but I was under the impression that you were indicating the ID of the bore.
     
  9. specweldtom

    specweldtom Well-Known Member

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    Nah Eddie, Since all my setups end up being made on the O.D., I just needed to know where the O.D. was in relation to the bore. If they are concentric at the breech and muzzle, setups on the O.D. will be accurate for the tenon, chamber, and crown.

    Hired Gun, I work in the chuck or in the steady rest, and 40 rpm to 63 rpm parting off, threading and chambering, and up to 400 rpm turning and facing with carbide tools (on barrel diameter work). I have spun a 31" finished length heavy varmint barrel at 400 rpm to semi polish it. I expected the .0075" runout to shake, so I worked up to 400 rpm in steps. No sweat. I'm not sure why it didn't vibrate, but it didn't. My lathe is a 13" swing x 72" between centers, and weighs about 2500 lbs. Maybe that helps, but probably .0075" just doesn't generate enough moment to shake a stiff barrel. I have run a 20" hvy barrel at 1000 rpm, also working up in stages. They polish better at the higher speeds. But even staging up, there is a pucker factor at 600 rpm or above. I wouldn't want to get hit by one that flew out, so I nearly always settle for 400 rpm max.

    I have a healthy respect for my lathe. I figure if I screw up, it'll beat me to death, or dismember me, or both. Keeps me on my toes.

    Tom
     
  10. Hired Gun

    Hired Gun Well-Known Member

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    Seven thousandths at home in the middle shouldn't be a big deal even at 2000 rpm. What I was getting is at 5000 rpm it I think the guy contouring it would have felt it and rejected it. Maybe not. I never check the outside. I work off the bore, one end at a time.