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View Full Version : Dialing in barrel with a long headstock/spindle length?



thisguy65
02-11-2016, 09:28 AM
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.

Dusty Stevens
02-11-2016, 10:41 AM
Some folks use the viper barrel fixture or homemade cathead. You can make your own.

Boyd Allen
02-11-2016, 11:09 AM
This is unique, expensive, and completely solves the problem in a very clever way.
http://www.straightshotgunsmithing.com/page25

thisguy65
02-11-2016, 11:27 AM
This is unique, expensive, and completely solves the problem in a very clever way.
http://www.straightshotgunsmithing.com/page25

But muzzle end of the muzzle is still unsupported (outboard end of the headstock)?

Boyd Allen
02-11-2016, 11:52 AM
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.

thisguy65
02-11-2016, 12:05 PM
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.


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.

DSM
02-11-2016, 12:44 PM
Make a spider on inboard side as close to spindle as possible and another on outboard side.

Boyd Allen
02-11-2016, 12:51 PM
If you have a long enough bed, the other interesting option is what I have called a mid bed headstock, so that you have a spider with its own bearing or bearings that is aligned with the headstock's CL. http://www.practicalmachinist.com/vb/gunsmithing/spider-place-steady-262387/

There have been a number of variations of this idea built. Some time back Speedy published the plans for one on Facebook.

thisguy65
02-11-2016, 12:53 PM
Make a spider on inboard side as close to spindle as possible and another on outboard side.

Still looking at 24-26"

skeetlee
02-11-2016, 02:06 PM
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

mks
02-11-2016, 05:21 PM
... an extension tube that I can slide over the barrel ...

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.

thisguy65
02-12-2016, 08:01 AM
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.

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?

Boyd Allen
02-12-2016, 12:08 PM
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

mks
02-12-2016, 12:41 PM
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?

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.

jackie schmidt
02-12-2016, 01:00 PM
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

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.

Gene Beggs
02-12-2016, 01:29 PM
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.


Works good! :)

skeetlee
02-12-2016, 01:47 PM
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

jackie schmidt
02-12-2016, 04:31 PM
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.

JerrySharrett
02-13-2016, 06:05 AM
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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skeetlee
02-13-2016, 10:56 AM
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

mks
02-13-2016, 01:20 PM
I would be interested to know if anyone has done ladder tests with the same barrel clocked at 6 and 12. (Just another one of those tests that I would do if I had more time...) Theory says that the 6 clocked barrel gives more compensation, because the line of the muzzle blast force runs higher above the center of gravity of the rifle. If the rifle needs more compensation, then 6 should help. If not, then 12 is better. It would also be a way, although inconvenient, of tuning for different yardages, i.e., 12 for 100 yards and 6 for 200 yards.

CMaier
02-13-2016, 05:28 PM
Lee,
Did anyone mention jackie nearly set a national record in group, shooting a 30 br, chambered his way ??



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

Zebra13
02-13-2016, 11:17 PM
Lee,
Did anyone mention jackie nearly set a national record in group, shooting a 30 br, chambered his way ??

CMaier,

So how do we explain somebody like Bob Brackney? Brackney and Brackney built guns have accounted for a lot of wood through the years and unless he's changed his ways, he chambers barrels using the steady/tailstock method. I believe the MacMillan .009 rifle was chambered the same way. We could probably peruse the record books and find record groups that were shot by rifles chambered in 40-eleven different ways.

My point? I think it's more about the Indian than the arrow. I think Jackie nearly setting a national record is more indicative of his shooting ability than his chambering method. In fact, if you look at the pictures of Jackie chambering a barrel, you can see he chucks directly on the barrel. No pivots, wires, or anything else. Now some would tell you that he's toiling about in the dark ages because he does that and doesn't have some sort of pivoting affair between the chuck and the barrel. In fact, if I'm correctly picturing how he holds his muzzle captive in the spindle, he may be bending his barrels! And yet he cleans his fair share of clocks on the range, with rifles not chambered in the "ideal" manner...

Kelly Johnson once said, "It doesn't have to be perfect, it just has to work".

Ben Hogan said, "The more I practice, the luckier I get".

But chambering discussions are sure a fun way to whittle away the winter days, aren't they?

Justin

CMaier
02-14-2016, 12:09 AM
Yes and at one time a front engined race car won the Indy 500,
but over time some people were willing to try new things, to learn .
To win by not following the crowd.
winter in socal is never un-nerving...just cloudy.



CMaier,

So how do we explain somebody like Bob Brackney? Brackney and Brackney built guns have accounted for a lot of wood through the years and unless he's changed his ways, he chambers barrels using the steady/tailstock method. I believe the MacMillan .009 rifle was chambered the same way. We could probably peruse the record books and find record groups that were shot by rifles chambered in 40-eleven different ways.

My point? I think it's more about the Indian than the arrow. I think Jackie nearly setting a national record is more indicative of his shooting ability than his chambering method. In fact, if you look at the pictures of Jackie chambering a barrel, you can see he chucks directly on the barrel. No pivots, wires, or anything else. Now some would tell you that he's toiling about in the dark ages because he does that and doesn't have some sort of pivoting affair between the chuck and the barrel. In fact, if I'm correctly picturing how he holds his muzzle captive in the spindle, he may be bending his barrels! And yet he cleans his fair share of clocks on the range, with rifles not chambered in the "ideal" manner...

Kelly Johnson once said, "It doesn't have to be perfect, it just has to work".

Ben Hogan said, "The more I practice, the luckier I get".

But chambering discussions are sure a fun way to whittle away the winter days, aren't they?

Justin

skeetlee
02-14-2016, 10:05 AM
Lee,
Did anyone mention jackie nearly set a national record in group, shooting a 30 br, chambered his way ??

Jackie is a fine shooter for sure. Much better than ill probably ever be! I would love to have Jackie's ability behind a rifle. Jackie is also a master machinist, and I am not. However, None of this, means I cant think for myself. Indicating a point 20 plus inches away from the business end of a barrel, ill never be able to rap my mind around. I'm not saying Jackie is wrong and I am right, I'm just saying when I think for myself, this doesn't make sense. And as long as your throwing out achievements, ill add a couple of my own. The last two years at the St Louis Benchrest club, a shooter that has been shooting my barrels has won shooter of the year. Not once, but twice! Second place, or runner up last year was also shooting barrels I chambered for him. Id say I am doing ok. I would also say that anyone that can feel .005 or even .015 of barrel run out at the muzzle during recoil has some serious shooting abilities. My method is working for me and the folks I'm doing work for, so for now I don't see any reason to change. That's the bottom line for me. Lee

Mike Bryant
02-14-2016, 06:19 PM
I used a shell reamer and reamed the spindle bore on my lathe. Then built a dead center that used pilot bushings to slip into the rear of the spindle. Lock it down with one of the four set screws tapped in the rear of the spindle. When it comes to the muzzle end of the barrel it's not that critical as to how closely it's centered. If it was, you couldn't push it over to get two spots lined up on the chamber end. IMO and that's all it is my opinion, the most critical part of a chamber is having the throat indicated in. I've indicated barrels in just about any way you can including pushing the muzzle out of line to get the butt end running true at the throat and start of the bore. Haven't seen it makes any particular difference as long as the throat is centered in the bore when the chamber is finished. If the throat comes out where it's off centered, freebore longer on one side that the other, more than likely the barrel won't shoot. As with everything, there are exceptions to the rules. It's a lot better feeling when you're done with the chamber to run a dial indicator into the neck and have no runout, run it at the back of the chamber and not have any runout. Then look at the throat with a borescope and have the throat is centered. That at least gives you an idea it should shoot. The final check and the one that counts is how it shoots on paper.

Zebra13
02-14-2016, 11:15 PM
Yes and at one time a front engined race car won the Indy 500,
but over time some people were willing to try new things, to learn .
To win by not following the crowd.
winter in socal is never un-nerving...just cloudy.

CMaier,

I think you missing my point. I'm not anti-progress, and thank God for the experimenters in bench rest...they've given us every major accuracy advancement in the past 50 years. Hell...Gordy Gritters is one of those experimenters who came up with a different way of chambering...and his method gets poo-pood by some. But it is my humble opinion that ability and practice mean more on the paper than your chambering method. Some would have you believe that if you don't chamber a certain way, you're an All-Conference jackoff. And I give you Bob Brackney, whose chambering method is generally considered less accurate than chambering through the headstock. But he wins, as do his rifles. How do we explain that?

Cloudy in SoCal? It was about 80 in CenCal today. The wife and I took the boat up to Nacimiento and caught about 20 Spotted Bass for Valentine's Day. Am I a romantic or what?

Justin

Louis.J
02-14-2016, 11:37 PM
Throwing an indivduals accomplishments on the table proves nothing as far as one's quality of workmanship is concerned. I have seen good competitors work around slight inaccuracys in workmanship do some amazing shooting by using their abilities to understand and shoot the conditions presented to them making a good rifle look great. Checking one's work when completed as outlined by Jackie Schmidt is the key for judging the quality of ones workmanship! Just as I have seen good workmanship look great I have also seen outstanding workmanship simply look good all based on the individual sitting behind the rifle.

thisguy65
02-16-2016, 12:21 PM
I have to ask this for setup.

If I have a barrel that is say 12" long blank that can't be any shorter. If I made a sleeve with set screws to extend the barrel. I think this would work to set the 2nd point to chamber or cut the muzzle.

If having a full blank that was just a little short I would thread the bore of the muzzle for a brass or steel rod. I'm more incline for steel or alum. instead of soft brass. This would allow me to cut the tenion and then I could switch to a extension that is more solid, thread round bar that is thread (ID) to screw on to the tenion.

CMaier
02-16-2016, 12:27 PM
thread the muzzle BORE..NO.
OD YES

I have to ask this for setup.

If I have a barrel that is say 12" long blank that can't be any shorter. If I made a sleeve with set screws to extend the barrel. I think this would work to set the 2nd point to chamber or cut the muzzle.

If having a full blank that was just a little short I would thread the bore of the muzzle for a brass or steel rod. I'm more incline for steel or alum. instead of soft brass. This would allow me to cut the tenion and then I could switch to a extension that is more solid, thread round bar that is thread (ID) to screw on to the tenion.