What I learned about dialing in a barrel

[DaveTooley]

do you have a D type spindle or is it threaded ? I just wonder cause I wonder how your inboard spider is made? I have D type chucks on all my lathes and so I think I could make them out of a back plate. thanks

On my manual machines the chuck backing plate provided enough meat for the screws.

 

[hoz53]

On my manual machines the chuck backing plate provided enough meat for the screws.

Thanks

 

[Edd]

...... So I dialed the area at the pivot point of the chuck shims to zero, then I dialed the breech to near zero. I checked the throat area and it was maybe .0003". Since this was a hunting rifle in a heavy recoiling cartridge, and I have a floating reamer holder that moves radially AND axially, I called it good. Also, the muzzle only had about .012" of runout. .....

I have never chambered a barrel and have no plans to ever chamber one but I have a question.

Why wouldn't you want to dial in the throat and the muzzle as close to zero as possible and then pre-bore the breech? Wouldn't that make all three points have no runout?

 

[butchlambert]

I have never chambered a barrel and have no plans to ever chamber one but I have a question.

Why wouldn't you want to dial in the throat and the muzzle as close to zero as possible and then pre-bore the breech? Wouldn't that make all three points have no runout?

You may not have chambered a barrel, but you understand machining.

 

[butchlambert]

the bore of barrels are not strait. dialing in the two points you mention doesnt guarantee the rest of the chamber is inline with the throat.

Sir, you might think a little bit before saying that. Now, tell me a better way to do it and why is it better?

 

[Alex Wheeler]

I have never chambered a barrel and have no plans to ever chamber one but I have a question.

Why wouldn't you want to dial in the throat and the muzzle as close to zero as possible and then pre-bore the breech? Wouldn't that make all three points have no runout?

Depends on your goal. If you want the crown directly in front of the chamber, thats how you do it. If you want the chamber coaxial to the bore in front of the chamber, thats not how you do it. You have to decide what is more important. Or source perfectly straight barrels and the end result will be the same with both methods. I have yet to find a dead straight one though. I have found some very close though and tracked them. They didnt shoot any better than the ones that were not very straight. But I feel some chambering methods handle those less straight ones better than others. If bores were all dead straight, no matter how you dialed it or even if you did it between centers, the result would be the same. The differences show up more the less straight a bore is.

 

[butchlambert]

Depends on your goal. If you want the crown directly in front of the chamber, thats how you do it. If you want the chamber coaxial to the bore in front of the chamber, thats not how you do it. You have to decide what is more important. Or source perfectly straight barrels and the end result will be the same with both methods. I have yet to find a dead straight one though. I have found some very close though and tracked them. They didnt shoot any better than the ones that were not very straight. But I feel some chambering methods handle those less straight ones better than others. If bores were all dead straight, no matter how you dialed it or even if you did it between centers, the result would be the same. The differences show up more the less straight a bore is.

Alex, I'll challenge you on that. If you indicate the throat and muzzle and prebore and ream, your chamber will be coaxial to the indicated throat. You have no control over what the bore does from the throat forward with any setup. A Gordy rod will not straighten a wandering bore.

 

[Alex Wheeler]

The chamber will be concentric to the exact point you dialed (the throat), but it will not be coaxial to that section of bore unless you have dialed in past the throat as well. I dont use a Gordy rod, or any rods at all. Im not saying one way is better, Im trying to avoid that very sensitive topic. I have my way and I do think its better, but Im not saying what that is. Im just describing the differences.

 

[butchlambert]

The chamber will be concentric to the exact point you dialed (the throat), but it will not be coaxial to that section of bore unless you have dialed in past the throat as well. I dont use a Gordy rod, or any rods at all. Im not saying one way is better, Im trying to avoid that very sensitive topic. I have my way and I do think its better, but Im not saying what that is. Im just describing the differences.

Tell me, how much does the barrel wander, say at the end of a seated bullet? Say it wanders .001 when all are talking tenths. Figure this a brown hair measures about .005 and a blonde one about .003.
I don't have any secrets in my chambering methods.

 

[Alex Wheeler]

You may see .0005 you may see .0015, depends on the barrel. Your arguing whats better. Im just describing how to achieve two different goals. I do have secrets, because I dont feel like arguing, when I do not care how others do it.

 

[butchlambert]

i knew that would probably bring out such a reaction. Just my opinion and I also think youre a man with alot more money than I have.

Money has nothing to do with chambering or good machining practices. All the fellow is saying and I agree is if you indicate the bore and the throat and prebore and chamber, you have 3 points that will indicate the same.
Sorry I got your goat Alex and really can't argue your chambering method as it is a secret.
I let you guys continue posting on this.

 

[Alex Wheeler]

Money has nothing to do with chambering or good machining practices. All the fellow is saying and I agree is if you indicate the bore and the throat and prebore and chamber, you have 3 points that will indicate the same.
Sorry I got your goat Alex and really can't argue your chambering method as it is a secret.
I let you guys continue posting on this.

Thats my point Butch, I dont want to argue. Im very happy with my results. I only commented on what is achieved with the different methods. Thanks!

 

[Stan Taylor]

I hope my customers aren't reading this post, I won't never get no more work I've been doing it wrong for 30years,an hope my customers don't want a refund, so much for my retirement I'm trying to save.LOL

 

[INTJ]

Gunsmiths are defensive and sensitive about their dialing and chambering methods. ALL these methods work and there are barrels chambered with each of these approaches that shoot exceptionally well. The most important method is what a particular gunsmith is best at. Anyone who says otherwise is full of BS......

I am not a machinist and have only chambered half dozen barrels. So far I have chambered one 6 BRA barrel that shot three consecutive sub 2" 3-shot groups at 1000 yds. It also won for two gun agg it's first match. My new 300 WSM LR BR rifle I built is hanging in at .3 MOA and has managed 1/4 MOA at 600. My 33-28 Nosler has shot 1/2" at 100 yds with 225 grain TTSXs at 3170 fps with an 8.75 lb rifle.

What that shows is it just isn't that hard to chamber an accurate barrel. What is hard is doing it quickly enough to pay the bills, and that what these guys like @butchlambert, @Stan Taylor, @DaveTooley, @Alex Wheeler, and others do every day. Not to mention action truing, timing, stockwork, and making everything look good.

So let the other guy dial in and chamber the way he likes.......

 

[Stan Taylor]

when i said i wanted to retire they said you allready been Retard around here a long time-- now wat should I do

It's in our blood we don't know the word quit we just stay after it until they close the lid on us one last time My friend.

 

[hoz53]

It's in our blood we don't know the word quit we just stay after it until they close the lid on us one last time My friend.

I guess so-

 

[tobnpr]

Impossible to dial three locations to zero runout without bending the barrel in the spindle to accomplish it in my mind.
I welcome someone explaining to me how it could be otherwise.

Dialing any section of the bore to be concentric with the axial rotation of the spindle requires two points- I believe this is what Alex was saying above as well. For me, it's the breech and the throat. If I tried to add the muzzle end to this equation I would need to bend the barrel unless it happened by sheer luck.

 

[Papa Charlie]

I have not chambered a barrel, yet, but wonder how you set up a barrel in a lathe using the breech and the throat before chambering?
I can see breech and muzzle. Unless when we say breech, we are talking the barrel OD and throat barrel ID.
Thanks for the education.

 

[butchlambert]

Impossible to dial three locations to zero runout without bending the barrel in the spindle to accomplish it in my mind.
I welcome someone explaining to me how it could be otherwise.

Dialing any section of the bore to be concentric with the axial rotation of the spindle requires two points- I believe this is what Alex was saying above as well. For me, it's the breech and the throat. If I tried to add the muzzle end to this equation I would need to bend the barrel unless it happened by sheer luck.

What Ed said was indicating 2 points, throat and muzzle. prebore your chamber and ream, then you have 3 points that indicate coaxial to the bore. No, the Gordy method or any other method will not make a straight bore.

 

[Alex Wheeler]

You get to pick 2 points to dial in a part, the centerline between those 2 points will be concentric to the chamber. Simple as that.