What tool / cutter setup do you use to turn rifle barrel shanks?

LVLAaron

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What's your setup to turn rifle barrel shanks?

I have a number of CCMT style inserts and parting blades that I feel comfortable with... and they work. But I'm fairly new to this and wondering... If I were to set a barrel back 1 thread, or just wanted to take a few thou off a shoulder to clock a barrel - what tool would you use?
 

Cadillac

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My guess is it’s gonna be hss ground to your taste. Carbide needs speed and d.o.c. For good finishes were as hss will do it better with lower speeds. Production carbide would have the advantage.
 

xr650rRider

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That SCLCR10-3B right hand turning tool in the set you bought from QMT with a CCGT 32.51 insert (silver ones). When you get to the shoulder with the diameter your after, bring the tool out with cross slide cutting the shoulder face. I'm usually turning 600+ rpm.
Be aware that taking 1 thread might not be enough to clean up a chamber that has a different sized neck. If the new neck is smaller diameter than the old one (ie, .268 vs .272), you'll have to setback the entire neck length.

Then if you listen to some of the really good gunsmiths, they'll never setback an old barrel due to dulling the reamer unless it's carbide. I've done it and I use a pressurized barrel flushing system. But $300+ for most new reamers from JGS makes you avoid it.
 
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xr650rRider

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Also realize that if a barrel is already headspaced correctly and you take some off the shoulder to clock the barrel, you also have to remove same amount off back of shank to keep bolt nose clearance the same, then you have to deepen chamber same amount to keep headspace the same.
 

LVLAaron

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Also realize that if a barrel is already headspaced correctly and you take some off the shoulder to clock the barrel, you also have to remove same amount off back of shank to keep bolt nose clearance the same, then you have to deepen chamber same amount to keep headspace the same.

Yep. Totally understand. After 1000-1200 rounds we've been setting everything back a thread and putting a fresh crown on. Gets you another 500 competitive rounds through the tube.
 

xr650rRider

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I'm confused. Why wouldn't you just do what we've been doing then? Use the same tools.
 

LVLAaron

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I've been having someone else do it... And I'm just curious how others might approach it.
 

xr650rRider

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I was in your same position a little over 2 years ago, I bought everything and tried many things. One thing I quickly learned is we'll probably always do a better job than sending it to a custom shop. I own 3 benchrest rifles with Kelbly's Stolle Panda actions. All of them are supposedly identical, meaning a barrel installed on 1 will fit the other 2. When I bought them they all came with extra barrels that had seen a lot of rounds. All these barrels were matched to that action. I've had 6 or 7 other barrels made that were from information kept with gunsmiths that originally barreled the action. I bought 2 6mm 1:8 barrels on an online forum from a well known smith in PA. I was going to change from 6PPC to 6BR and needed the bolt diameter opened up, so they would handle both cases. Smith said no problem and will not need actions as all Pandas are identically machined. Both bolts were prestine and wanted to make sure the bolt faces were not touched so as not to screw with headspace problems. Again no problem. 6 months later when I got bolts and barrels back, one bolt face had been deepened .004", 1 barrel would screw on 1 action and not the other, 1 barrel wouldn't screw on either. Sent barrel back and it came back and fit loosely on either. Poured chamber casts and both chambers were crooked. The barrels were functional and headspaced with gauges within tolerance, so I shot them and they didn't shoot terrible. But it made me buy a lathe and mill. Then I set about measuring all of those different barrels and they were all over the map. Kelbly's provides a schematic on exact tolerance on threading and chambering and only 1 barrel actually matched those specs. A couple had cone angles off a few degrees, bolt nose clearances that basically had the case head unsupported and at risk of case failure. Gunsmith in business to turn out work can't take 4 hours to indicate a barrel in to < .0002" of runout. I think some do but it depends on who they are selling to and whether your a known shooter or not. Regular ole guy buying a barrel won't know any better. You won't either until you build the tools to measure them. I use a grizzly rod to dial in close initially then use an Interapid 312B-15 DTI to indicate directly on the lands and dial in to where I see virtually identical land to land. Usually dialing in a 3" or so area that is running exactly true to the spindle. This means the muzzle ends up where it ends up. Some of these barrels have horrible runout on the muzzle end when the chamber is running true. Most of these are Kreiger barrels, couple Shilens, 1 Bartlein. A couple barrels have virtually 0 runout on both ends. The point is, smiths like Alex Wheeler would not have even used those barrels with runout like that, he would have sent them back and exchanged them. Where do those end up? Sold online by someone else. I think it was in Tony Boyer's book where he talks about buying barrels by the dozens. They are chambered and tested, if they don't shoot great from the start, they are sold.
So doing it yourself, you can take the time and get them dialed in to the best of your abilities and you'll learn much in the process. That still doesn't mean they'll all be hummers. In the end, the target is only thing that matters.
 

xr650rRider

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One thing worth mentioning and you might not have this problem. Biggest source of frustration dialing in barrel was brass tipped screws. Probably adjusting them too tight but nothing like getting close and your tip crushes or distorts and throws everything off. I changed over to using aluminum pads with a ball bearing tip on adjustment screws on inboard and outboard spiders. Made a world of difference in speed of dialing in. Also make sure outboard spider and inboard side, whether spider or chuck, that the jaws or adjuster screws are aligned the same.

Making those aluminum pads is pretty easy with mill and annular cutter. Used some 1/8" aluminum and made a 5/16" depression with a ball nosed mill, then drilled out with maybe 3/4" annular cutter and the ejected piece is your pad. I have 5/16' ball bearings tig welded onto end of 3/8"-24 adjustment bolts.
 
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