Lets discuss the "other" method of barrel chambering. (kind of long)

[Curious]

The reason I say two points is because when dealing with a piece, (i.e., the ID of a barrel), that is not straight with it's own self, all you can hope for is to get two points true.

Be willing to check your work. How many of you actually do?

Better yet, how many of you actually know how.

Can I ask what the two point are? I figure one is the throat.

Can I also ask what method you use to check your work please?

 

[adamsgt]

I took a Kreiger barrel to a local gunsmith to chamber it in 30BR for my HV gun a Bat action. His lathe chuck was a Jacobs rubber one and he used a steady rest. I was there as he performed all the operations. Unfortunately I didn't take good notes and can't replicate his process. However, he, not once, used any sort of dial indicator. And, the barrel shoots. I don't know what to say beyond that.

 

[JerrySharrett]

I still make the argument that for a barrel to produce the most precision, why would you NOT want the exit point of the bullet to point in exactly the same direction as the centerline of recoil?

As to chucking on copper wire, probably not the best. I chuck on the first 1/4" of pre 1982 copper pennys. This gives a more sound hold while allowing the barrel to be in a non-stress hold. Why pre 1982 pennys? Those were solid copper, not this pot-metal crap we are provided today by the greedy government we are living under.



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[jackie schmidt]

Can I ask what the two point are? I figure one is the throat.

Can I also ask what method you use to check your work please?

Assuming that ALL machining operations on the chamber end are performed on the same setup, here is how you check it before removing the barrel

Take your "tenth" indicator and reach in to the lands and grooves just past the throat that the reamer cut. Take a reading. Then move the indicator to the neck area, take a reading. Then, move it to the back of the chamber. Take a reading. Then, moving to the OD, place the indicator stylus on the barrel shoulder. Take a reading. Next, place the lathe back into threading mode, and engage the half nut. Place the indicator stylus in the V of the thread, and roll the chuck with a steady motion so as to keep all the slack out. Take a reading.

All of these indicator readings should run within .0005 or so of each other.

By the way, the other "point" you referred to is predicated on how you true your barrels in the beginning. That is an entirely different subject.

 

[Zebra13]

Assuming that ALL machining operations on the chamber end are performed on the same setup, here is how you check it before removing the barrel

Take your "tenth" indicator and reach in to the lands and grooves just past the throat that the reamer cut. Take a reading. Then move the indicator to the neck area, take a reading. Then, move it to the back of the chamber. Take a reading. Then, moving to the OD, place the indicator stylus on the barrel shoulder. Take a reading. Next, place the lathe back into threading mode, and engage the half nut. Place the indicator stylus in the V of the thread, and roll the chuck with a steady motion so as to keep all the slack out. Take a reading.

All of these indicator readings should run within .0005 or so of each other.

By the way, the other "point" you referred to is predicated on how you true your barrels in the beginning. That is an entirely different subject.

Gents,

Jackie's mantra of "check your work" is some of the best advice I've got from this forum. And I just learned another gem with his direction on how to check the barrel tenon threads. Would have never thought of that...

Thanks, Jackie.

Justin

 

[Pete Wass]

Question:

Once one chambers a barrel and then checks it and something is grievously wrong, what can one do about it? Assuming one has shortened the barrel to where they do not ant to make it any shorter.

My guess is that we would shoot it and if it shoots, great. If it doesn't, try harder next time?

A feller in the barrel fitting bidness told me that the first barrel he chambered he did in a regular 3 jaw chuck and it shot great. He insinuated that we may be over thinking this subject. Of course, the closer we can get to perfection, the less chance we have to create an error but I am thinking barrels sometimes will forgive quite a lot.

Pete

 

[jackie schmidt]

Once one chambers a barrel and then checks it and something is grievously wrong, what can one do about it? Assuming one has shortened the barrel to where they do not ant to make it any shorter.

My guess is that we would shoot it and if it shoots, great. If it doesn't, try harder next time?

A feller in the barrel fitting bidness told me that the first barrel he chambered he did in a regular 3 jaw chuck and it shot great. He insinuated that we may be over thinking this subject. Of course, the closer we can get to perfection, the less chance we have to create an error but I am thinking barrels sometimes will forgive quite a lot.

Pete

You are probably right. About all of it.

But the truth is, in my line of work, we are compelled to do things right, all of the time. True, every machined piece has a tolerance, but these tolerances are not "suggestions".

I strive to do every barrel to the best of my ability because I know I can. If I know something does not meet my standards, it is no different than letting a job get out of the shop that I know something is not quite correct.

 

[Pete Wass]

I understand completely

You are probably right. About all of it.

But the truth is, in my line of work, we are compelled to do things right, all of the time. True, every machined piece has a tolerance, but these tolerances are not "suggestions".

I strive to do every barrel to the best of my ability because I know I can. If I know something does not meet my standards, it is no different than letting a job get out of the shop that I know something is not quite correct.

I think most people who aren't professional machinists simply do the best they can and live with the results. What else can they do, realistically? It takes a lifetime to learn a skill to perfection and most DYI people don't have the time to become professionals. Many people like me may understand the principals but being able to do it all well takes a working lifetime. I do understand there is a "Feel" that comes with having done anything for a very long time and I will be the first to say, I never developed one for machining and @ 71 I don't have any illusions of the "feel" coming to me any time soon. I spent my working career trying to figure people out so I know quite a lot about that.

I have an old South Bend 10L and chamber through the spindle. I am an equipment freak so have ten or a dozen indicators. I zero the barrels until they do not move the dial on a .0005 indicator using ground pins to indicate on, front and rear. What happens after that is where the feel comes, I suspect and I know it takes a long time to develop that and I don't have enough time left to get there, I don't believe.

I have always questioned cutting a chamber into a banana, long before I ever started doing it. From what I have seen in results, it makes little or no difference. The most sensible thing is the way you do it, IMHO.

Pete