Mike Rock Ballels

ooooo and the metal knows the difference?
I'll buy that it will move after firing but before firing unless it hasnt been heat treated and stress releived it wont change. Metal does not act that way when correctly heat treated. It doesnt move because it has a bore it moves because stresses in the material havent been delt with correctly.
Go drill a hole in a piece of round stock then turn the outside and let me know if the id gets bigger. It wont. Now pull a rod slightly bigger through the predrilled hole (simulating button rifling) and turn the outside and id say it will change (without any heat treating or stress releiving). Heat treat it and stress releive it and it wont change dimensionally.
i'd say that the reason Chris has seen a dimensional change is because of the amount of barrels hes worked with, I would also suspect that the ones that have moved if a metallugist were to examine it it would be defective in some manner conducive to allowing movement through improper heat treating and stress releiving. I would say that we shall never know as not to many of us have access to such equipment and have such indepth knowledge as to assess the materials composition enough to make an informed finding.
This all centers around the way a material acts not if its being done by a gunsmith or a machinist. Its all metal work and metal reacts the same no matter whos machining it.
They dont have a gunsmithing edition of Machinerys handbook its just the machinerys handbook. This is because it is a standard for everyone who works with metal to go by not just gunsmiths or machinist but everyone.
I am not doubting Chris but I have been to school for metallurgy and what is being discussed here goes against how material reacts in reference to heat treating or not.
Simply turning the outside diameter in itself will not change internal bore dia provided it has been correctly heat treated and stress releived.

[BountyHunter]

Got to agree with those saying the inside barrel dimensions will/can change if the outside is machined down.

For anyone taking Precision Shooting there has been a series of very enlightening articles by Bill Calfee the premier 22LF BR smith. He talks about "slugging" barrels to determine exact variations in a "perfect" bore to determine the best point for the crown and which end to even be the breach and crowns. In one of his articles he talked about that very thing and what dimensional changes he noted. He also talked about using set screws to put a barrel tuner on the end of the barrel and he can measure the restriction from 4 small set screws.

Tim North (Broughton barrels) uses basically the same technique to establish his crown and does not recommend retapering barrels after being bored and rifled.

You can disagree but I sure would not spend $300 on match grade barrel and then screw it up with reprofiling it. Now if all I wanted was hunting grade barrel, then go for it.

BH

[Michael Eichele]

Daveosok,

I am not doubting your abilities as a machinist or your knowledge about metals. I am sure you are quite good at your craft. The bottom line is that I was just a little preturbed by your statment of what I had to say as being "BS". That said, I am sorry if I had a slightly demeaning tone in my last post. I do however feel that there is a solid basis for my statments. I AM NOT saying you are wrong. There is alot of truth to many things you stated and can agree with much of it. I am not asking you to agree with me. I dont care who is right and who is wrong. I am sure we both have some of it right. So maybee we can agree to dissagree gracefully.