Dialing in barrel with a long headstock/spindle length?

T

thisguy65

Guest
Hey guys,

May be getting a Nardini lath and they are known to have wide head stock. Question is what are some setups guys have ran to support the muzzle end of the chamber? I know of a bushing method but seems like it would be a pain in the butt to have make a bushing for each barrel. Plus the bushing would be going off the OD and not the bore so the adjustment wouldn't be there for the muzzle end, correct?

I rather go off the headstock than between centers personally.
 
With a spider on the outboard end, some sort of provision is made so that the barrel can pivot in the chuck jaws. With this setup, this is not necessary because all of the adjustment is done at the chuck end. I would suggest that you contact the manufacturer for details. Obviously, if there were not parallel section, some sort of adapter would have to be made, perhaps a shrink on aluminum sleeve that was turned between centers after mounting on the barrel. In any case, for barrels that have some parallel shank in front of the tenon, I think that this is a brilliant solution. The other thing to consider is the usual speed used for chambering.
 
Boyd Allen said:
With a spider on the outboard end, some sort of provision is made so that the barrel can pivot in the chuck jaws. With this setup, this is not necessary because all of the adjustment is done at the chuck end. I would suggest that you contact the manufacturer for details. Obviously, if there were not parallel section, some sort of adapter would have to be made, perhaps a shrink on aluminum sleeve that was turned between centers after mounting on the barrel. In any case, for barrels that have some parallel shank in front of the tenon, I think that this is a brilliant solution. The other thing to consider is the usual speed used for chambering.
Click to expand...


Thanks for the explanation. Seems as the system is a fancy set thru chuck.

lets go off for a second and say this TBAS was non-existent. Now what? Even in his videos he uses a rear spider.
 
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My big 16 inch grizzly is pretty long in the head stock. What I did for the shorter barrels is simply make an extension tube that I can slide over the barrel and give the barrel the added lengh it needs to go out to the outboard spider the lathe came equipped with. I tapered one end of my extension tube to roughly match the barrel contour . I secure the extension with brass tip set screws. The taper inside the extension also centers itself onto the barrel. On the reverse end of the extension I cut threads. I can then use the threaded end on the finished chamber so I can cut the crown.
Hope this makes since. I'm on my cell phone so I'm not proof reading. Good luck. Lol. Thanks lee
 
skeetlee said:
... an extension tube that I can slide over the barrel ...
Click to expand...

A similar idea - if you are going to install a tuner, go ahead and thread the muzzle for a tuner, and screw an extension onto the threads.
 
mks said:
A similar idea - if you are going to install a tuner, go ahead and thread the muzzle for a tuner, and screw an extension onto the threads.
Click to expand...

If you did this you wouldn't be able to indicate off the bore since the breech would be "free floating" in the spindle, no?



Lee, how long are you tapering and at what degree (on the compound) if you remember? Thinking a 3-4" taper would be good enough?
 
What you seem to be unaware of is that a number of skilled gunsmiths do not indicate in their barrels at both ends but instead in a segment of the bore at the chamber end. In order to do this the muzzle ends up off center to some degree, but the thought is that the alignment of the chamber to the bore is more important. As a part of this process, the barrel is indexed so that the curvature of the barrel is pointed up relative to the action. Similarly, when a crown is done, the same procedure is followed, so that the chamber end is not centered at the off end of the spindle, but the muzzle is, as well as the section of the barrel that is immediately behind it. Here is a video that is an excerpt of one that Gordy Gritters sells for instruction, that demonstrates what I am talking about.

https://www.youtube.com/watch?v=aII2tbavKnM&list=FLuTrbMDzH6BqrbYtjeAXU6g
 
thisguy65 said:
If you did this you wouldn't be able to indicate off the bore since the breech would be "free floating" in the spindle, no?



Lee, how long are you tapering and at what degree (on the compound) if you remember? Thinking a 3-4" taper would be good enough?
Click to expand...

Right, these extensions are more useful for the method that aligns the chamber and lets the muzzle go wherever it wants. Although, you could use a hollow extension and reach in with a long indicator to center the muzzle if you were so inclined.
 
Boyd Allen said:
What you seem to be unaware of is that a number of skilled gunsmiths do not indicate in their barrels at both ends but instead in a segment of the bore at the chamber end. In order to do this the muzzle ends up off center to some degree, but the thought is that the alignment of the chamber to the bore is more important. As a part of this process, the barrel is indexed so that the curvature of the barrel is pointed up relative to the action. Similarly, when a crown is done, the same procedure is followed, so that the chamber end is not centered at the off end of the spindle, but the muzzle is, as well as the section of the barrel that is immediately behind it. Here is a video that is an excerpt of one that Gordy Gritters sells for instruction, that demonstrates what I am talking about.

https://www.youtube.com/watch?v=aII2tbavKnM&list=FLuTrbMDzH6BqrbYtjeAXU6g
Click to expand...

Some very well known shooters use this method.

The big problem with that " curvature of the barrel" thing is it is not consistant through the bore.

A while back, we did a test on this on an old unlimited barrel. I scribed a straight line down the OD, and then parted the barrel into 4 inch sections. The ID wandered quite a bit in relation to the OD.

It's in the archives somewhere.
 
Jackie
this very well may be, but I have done even further testing here at my home range.
I do indicate my run out at either 6 or 12 o'clock depending on what the barrel is being used for, and what position is closest. However, I forever have wondered just how important this was to accuracy. Long story short. For short range benchrest I haven't found any conclusive evidence that indicating the run out to 12 or 6 O'clock has any adverse effects on accuracy. I have on several occasions let the run end where it may be, and the barrels will still shoot in the teens. I have proven this to myself enough times now, ill swear it to anyone. Minor scope adjustments is the only downside I can find...
Long range shooting, I haven't tried this, so I can not say. I indicate the throat, and then again 2 to 3 inches in front of the throat. everything behind the throat is bored true. I know my bullet starts straight with this method and I am very comfortable with it. Lee
 
Skeet, one of the results of doing barrels the way I do is the muzzle is always pointed in the same direction in relation to the barrel threads and action face.

I have three barrels ready for this years Group Shooting Season. All three of those barrels will hit amazingly close to each other on the target at 100 yards when I change from one to the other.
 
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In our world of trying to get the last 0.002" out of a benchrest rig, I just can't see not having the muzzle pointing in the same direction as the rest of the rifle.

I chamber through the headstock on a lathe where I can indicate the BORE on both ends. This allows me to, when swapping barrels, to be within +/- 2" at 100 yards. If I had to go look for the first bullet hole somewhere way off the target I would not have confidence in that setup.

Ranges are supposed to have a zeroing target set up for anyone that had to swap barrels during an event. I have seen some barrels chambered using these "range rods" not even be on the paper at 100 when the paper is 24" x 24". Not me.


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I understand the hole impact thing I truly do, however how hard is it to reach up and give the scope a couple extra clicks? during my testing the worst Impact shift I came across was only 2 inches. It took me about 3 seconds to correct that with a couple fouling shots that we are going to take anyway. I'm not advocating not timing the barrel. I always do, however ill never be able to rap my mind around indicating at both ends. I just cant see how a point 20 inches away from the work end has any real barring. Lee
 
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