Your chambering guy

[wildchild]

So ya spend $300 plus dollars and wait 6 plus months to receive your barrel, then ya gotta have a trust worthy prospect to cut a chamber and thread so you can go about your business shooting it after he charges X amount of dollars. My question is can he cut a chamber to print and back it up???
If you have a .330 neck 30 br can you fit a .331 gauge pin in it?!!! how about a .332
If so, what just happened to your freebore that was cut in your reamer to .00 or say .020 or the brass movement from the "custom die for chamber" of one chamber to the new one.
If he didn't do it, do we live with it and hope he does a better job next time? Who has had a chamber cut from same reamer on different barrels and seen a drastic difference in free bore and a set measurement to reach the lands and scratched there heads in confusion?? Id bet at least 100 members... 8)
Food for thought I guess ;D ;D
Dont everyone at once get up and measure there chambers ;D

 

[Gundoktr]

Fat chance of getting a reamer with a .337 neck t cut a .337 neck! Reamers don't always cut to size. Besides, only a fool would guarantee accuracy from a rifle he built. Too many variables; he don't know what kind of a shooter you are, reloader, etc.

My guarantee: You will be happy with what you get.

 

[gunsandgunsmithing]

Don't forget...chambers aren't the only thing that has tolerances. As blessed as we are to have great reamer makers, reamers are just like everything else...they have tolerances too, as do lathes. Temps affect final dimensions as well, particularly when splitting frog hairs that we do when speaking in terms of .0001". Most people have no idea what that means, much less do the understand machining to those tolerances. A reamer can't ream a hole smaller than itself, and the tolerance is on the + side, around .0004" on reamer's od. With a reamer on the big side and a .0002" runout, it's easy to conceive a full .001" oversize from stated dimension. Measuring to .0001" is a much different exercise than machining to .0001". People throw those kinds of dimensions around like they are common practice...they are not. Even in a lab environment, we are still measuring with a micrometer and cutting with a "hacksaw", so to speak, as things such as tool stress, deflection and temperatures all affect the final dimensions, not only of the chamber, but the reamer when it's made. Because we don't live in a perfect world, we have custom dies...that by the way, aren't perfect either, nor are the barrels we use. You asked about what would happen to freebore if the chamber were a bit big...what about the barrel? What if the land and/or groove dimensions were on the big side? Obviously, the reamer won't begin to cut as soon and the freebore will be different. Just some things to consider, as many assume perfection in the tools and components that the gunsmith has to work with. That simply is not the case. As I said, everything has tolerances. We are fortunate to have great barrel, action, and reamer makers, as well as great smiths to make it all come together. All that said, if you have a neck dimension that's .002" over, I'd talk with the smith and get to the bottom of why it's that far off.--Mike

 

[Bob3700]

If you are using your own reamer, the freebore should remain the same, within reamer tolerances.

Your gunsmith should be able to hold the headspace dimension to the point where brass should interchange between bbls.

With the tooling available today, there is no excuse for a headspace or throat dimension (length) being out of your spec. Heck, home hackers like me can accomplish that, the pros should be that much better.

You will get what you pay for in most instances. The well known smiths have long waits cause they do good work and the target confirms their quality. That is why you pay and wait.

Bob

 

[wildchild]

Fat chance of getting a reamer with a .337 neck t cut a .337 neck! Reamers don't always cut to size. Besides, only a fool would guarantee accuracy from a rifle he built. Too many variables; he don't know what kind of a shooter you are, reloader, etc.

My guarantee: You will be happy with what you get.

I know a retired machinist that does and guaranties it!!
this isnt about guaranteeing accuracy, but why have these fabulous barrel makers and bullets guys like Berger going out of there way so we can shooot out of oversized chambers.
lots of talk about Lapua changing brass thickness in the necks and big 5 page threads on what neck dia. to order in a reamer only to have it chambered bigger than the print. :

 

[wildchild]

Don't forget...chambers aren't the only thing that has tolerances. As blessed as we are to have great reamer makers, reamers are just like everything else...they have tolerances too, as do lathes. Temps affect final dimensions as well, particularly when splitting frog hairs that we do when speaking in terms of .0001". Most people have no idea what that means, much less do the understand machining to those tolerances. A reamer can't ream a hole smaller than itself, and the tolerance is on the + side, around .0004" on reamer's od. With a reamer on the big side and a .0002" runout, it's easy to conceive a full .001" oversize from stated dimension. Measuring to .0001" is a much different exercise than machining to .0001". People throw those kinds of dimensions around like they are common practice...they are not. Even in a lab environment, we are still measuring with a micrometer and cutting with a "hacksaw", so to speak, as things such as tool stress, deflection and temperatures all affect the final dimensions, not only of the chamber, but the reamer when it's made. Because we don't live in a perfect world, we have custom dies...that by the way, aren't perfect either, nor are the barrels we use. You asked about what would happen to freebore if the chamber were a bit big...what about the barrel? What if the land and/or groove dimensions were on the big side? Obviously, the reamer won't begin to cut as soon and the freebore will be different. Just some things to consider, as many assume perfection in the tools and components that the gunsmith has to work with. That simply is not the case. As I said, everything has tolerances. We are fortunate to have great barrel, action, and reamer makers, as well as great smiths to make it all come together. All that said, if you have a neck dimension that's .002" over, I'd talk with the smith and get to the bottom of why it's that far off.--Mike

Good post

 

[gunsandgunsmithing]

Don't forget...chambers aren't the only thing that has tolerances. As blessed as we are to have great reamer makers, reamers are just like everything else...they have tolerances too, as do lathes. Temps affect final dimensions as well, particularly when splitting frog hairs that we do when speaking in terms of .0001". Most people have no idea what that means, much less do the understand machining to those tolerances. A reamer can't ream a hole smaller than itself, and the tolerance is on the + side, around .0004" on reamer's od. With a reamer on the big side and a .0002" runout, it's easy to conceive a full .001" oversize from stated dimension. Measuring to .0001" is a much different exercise than machining to .0001". People throw those kinds of dimensions around like they are common practice...they are not. Even in a lab environment, we are still measuring with a micrometer and cutting with a "hacksaw", so to speak, as things such as tool stress, deflection and temperatures all affect the final dimensions, not only of the chamber, but the reamer when it's made. Because we don't live in a perfect world, we have custom dies...that by the way, aren't perfect either, nor are the barrels we use. You asked about what would happen to freebore if the chamber were a bit big...what about the barrel? What if the land and/or groove dimensions were on the big side? Obviously, the reamer won't begin to cut as soon and the freebore will be different. Just some things to consider, as many assume perfection in the tools and components that the gunsmith has to work with. That simply is not the case. As I said, everything has tolerances. We are fortunate to have great barrel, action, and reamer makers, as well as great smiths to make it all come together. All that said, if you have a neck dimension that's .002" over, I'd talk with the smith and get to the bottom of why it's that far off.--Mike

Good post

Thank you! I didn't mean to diminish or take away from the great quality of workmanship that we have available in this niche field. I just see many throw out numbers that simply aren't reasonable in the real world, for all parties involved along the way to having even the best guns. I say this because it's true. I came into gunsmithing by way of the tool and die making field. I understand what's involved in doing work to the standards that are quoted and claimed by many. The reality is that there are several good gunsmiths that do a great job, with plenty of pride in what they do. This is what you pay for....not so much the capability to hold better tolerances, but the desire to do the best we can do for our customers. Thankfully...that's very damn good in most cases, amongst BR smiths.

 

[jonbearman]

I would suggest gretan rifles or bob green in pennsylvania for a fair turn around.I had a known guy chamber my new 6 br 5r rifled barrel that wasnt cheap.He made a mistake and chambered it fo 6mm rem. I sent it back and he shortened the barrel alittle and made the chamber as tite as any I have owned. People make mistakes but be patient and dont bug them to hurry up.If you do,then things go wrong.You have to work with them and believe me they know their craft. Nobody is perfect and this fella will always get my business as he didnt balk at fixing the mistake.I personally think the guy is a stand up guy all the way.

 

[jonbearman]

One more thing,lathes are not capable of .0001 th's and the only thing that can hold those kind of tolerances as I was a precision grinder for 20 plus years is a grinder using electronic indicators and gage blocks that are calibrated in the millionth's.

 

[X Ring Accuracy]

Don't forget...chambers aren't the only thing that has tolerances. As blessed as we are to have great reamer makers, reamers are just like everything else...they have tolerances too, as do lathes. Temps affect final dimensions as well, particularly when splitting frog hairs that we do when speaking in terms of .0001". Most people have no idea what that means, much less do the understand machining to those tolerances. A reamer can't ream a hole smaller than itself, and the tolerance is on the + side, around .0004" on reamer's od. With a reamer on the big side and a .0002" runout, it's easy to conceive a full .001" oversize from stated dimension. Measuring to .0001" is a much different exercise than machining to .0001". People throw those kinds of dimensions around like they are common practice...they are not. Even in a lab environment, we are still measuring with a micrometer and cutting with a "hacksaw", so to speak, as things such as tool stress, deflection and temperatures all affect the final dimensions, not only of the chamber, but the reamer when it's made. Because we don't live in a perfect world, we have custom dies...that by the way, aren't perfect either, nor are the barrels we use. You asked about what would happen to freebore if the chamber were a bit big...what about the barrel? What if the land and/or groove dimensions were on the big side? Obviously, the reamer won't begin to cut as soon and the freebore will be different. Just some things to consider, as many assume perfection in the tools and components that the gunsmith has to work with. That simply is not the case. As I said, everything has tolerances. We are fortunate to have great barrel, action, and reamer makers, as well as great smiths to make it all come together. All that said, if you have a neck dimension that's .002" over, I'd talk with the smith and get to the bottom of why it's that far off.--Mike

Amen. We do the BEST we can but life gets in the way. Well stated.

 

[txdan]

.0001 ? Try this. Take a sheet of paper and cut it into 4- 8 1/2"X11" sheets. Then cut one of those into 10- 8 1X2"X11" sheets. Then talk to your gunsmith about the tolerances you require. We are blessed with outstanding craftsmen who do not get credit where credit is due.

 

[wildchild]

How about spending a bunch of time indicating in a barrel then float a reamer? :

 

[butchlambert]

How about spending a bunch of time indicating in a barrel then float a reamer? :

And your point is?

 

[Cigarcop]

How about spending a bunch of time indicating in a barrel then float a reamer? :

If you have the bore running true where else could it go?

 

[wildchild]

How about spending a bunch of time indicating in a barrel then float a reamer? :

If you have the bore running true where else could it go?

oversized, it floats around. not?

 

[butchlambert]

wildkid,
I don't use a floater, but if it is indicated properly, drilled, and prebored, what difference would it make. Have you worked in a machine shop?

 

[jscandale]

I think what windchill is maybe asking is can the chamber ream bigger if the floating reamer is not floating properly. If that is what you are asking, then I think it probably could. Let just say as a hypathetical example, a smith chucked a barrel in a standard 3 jaw chuck and did not indicate the bore. It's probably safe to say that the bore's runout is maybe .010-.020", not to mention the since the bore is cockeyed in relation to the spindle. In this case, and it's a pretty exagerated example, if in addition to such poor setup, the floater was not floating properly, the chamber would certainly cut significantly larger than expected.
If this is not what windchill was asking, then I just wasted a minute of your time...sorry.

JS

 

[butchlambert]

If I did not have a setup to properly dial in the bore, I would use a floating holder. If you had a properly dialed in bore, drilled, and prebored, it would take a very terrible floating holder to ream an oversize bore and it would be larger at the base.

 

[gunsandgunsmithing]

in in my experience the rate of feed and pre boring have more to do with the final hole dimensions than anything else.

 

[Cigarcop]

If I did not have a setup to properly dial in the bore, I would use a floating holder. If you had a properly dialed in bore, drilled, and prebored, it would take a very terrible floating holder to ream an oversize bore and it would be larger at the base.

Yep, drilled then bored...it would be awfully hard for the reamer not to want to follow that hole