why?

[Earl]

I have three good friends that are competition shooters and outstanding benchrest gunsmiths, All of them dial in their barrels to the the "half tenth" or better. When talking about "dialing in a barrel" we are talking about the bore, not the outside of the barrel. Lester uses a .00005 indicaor and adjusts his set-tru chuck until he sees no movement on the indicator. Bob does not use a pilot on his reamers. Lester and Gary do. Gary pre-bores the chamber, Lester does not. Bob uses a steay rest, Lester and Gary chamber thru the headstock. No matter what the method, most everyone "dials in" to get the bore (at the chamber end) running as tru as they can possibly get it. I have seen it take 45 minutes to get the bore dialed in. I have also talked with a champion long range shooter (1000 yard) that poo-poos the whole process and claims that he chambers a barrel in less than 30 minutes and uses vice-grips to hold the reamer!!! I did not believe that at first and then I heard the same thing about him from some other trustworthy sources so I now believe it is true.

The target is the only thing that really counts. Pick the method that sounds most reasonable to you and do it. Check your results. Try a different method and see how it goes. The target will tell you if you did a good job. (a borescope will make you feel good about your work but looking good does not indicate that it will shoot well) I have a Heavy 10 and a 12 x 36 grizzly. I do the rifle barrels on the heavy ten thru the headstock. I used the steady rest method to chamber a few inch and a half barrels for my rail gun. (heavy 10 only has a 1 3/8 bore) I don't like that method (screws up the finish on the outside of the barrel so I bought the grizzly) I have floating reamer holders (bald eagle) a straight pusher (gre-tan) and sometimes just use a tap wrench to hold the reamer and push it with a center. I have the Lambeth-kiff reamer stop setup. I have pilots up the kazoo even though I chamber in just a couple of cartriges. I have only chambered about 35-40 barrels so I am not really an expert but I do hang out at with my friends a lot and they all have their own reasons for doing it their way. Don't spend a lot of time worring about the best way to do it. Use the tooling that you have access too and try to spen more time at the range than behind the lathe.

Earl

 

[Tozguy]

thise discusion more "what if " just to let the ideas flow
before i make up my mind on the way i want to go to cut my chambers

As Earl pointed out those that have 'gone before' us have chosen a method that suits their tooling and (I would add) their personality. There is no single best way. JT you have asked some good questions about machining. There is a lot of pleasure from knowing that you thought it through and did the best job possible with your equipment.
In my opinion there are few shooters, if any, who can evaluate a chamber job with a target.

 

[JT.]

I have three good friends that are competition shooters and outstanding benchrest gunsmiths, All of them dial in their barrels to the the "half tenth" or better. When talking about "dialing in a barrel" we are talking about the bore, not the outside of the barrel. Lester uses a .00005 indicaor and adjusts his set-tru chuck until he sees no movement on the indicator. Bob does not use a pilot on his reamers. Lester and Gary do. Gary pre-bores the chamber, Lester does not. Bob uses a steay rest, Lester and Gary chamber thru the headstock. No matter what the method, most everyone "dials in" to get the bore (at the chamber end) running as tru as they can possibly get it. I have seen it take 45 minutes to get the bore dialed in. I have also talked with a champion long range shooter (1000 yard) that poo-poos the whole process and claims that he chambers a barrel in less than 30 minutes and uses vice-grips to hold the reamer!!! I did not believe that at first and then I heard the same thing about him from some other trustworthy sources so I now believe it is true.

The target is the only thing that really counts. Pick the method that sounds most reasonable to you and do it. Check your results. Try a different method and see how it goes. The target will tell you if you did a good job. (a borescope will make you feel good about your work but looking good does not indicate that it will shoot well) I have a Heavy 10 and a 12 x 36 grizzly. I do the rifle barrels on the heavy ten thru the headstock. I used the steady rest method to chamber a few inch and a half barrels for my rail gun. (heavy 10 only has a 1 3/8 bore) I don't like that method (screws up the finish on the outside of the barrel so I bought the grizzly) I have floating reamer holders (bald eagle) a straight pusher (gre-tan) and sometimes just use a tap wrench to hold the reamer and push it with a center. I have the Lambeth-kiff reamer stop setup. I have pilots up the kazoo even though I chamber in just a couple of cartriges. I have only chambered about 35-40 barrels so I am not really an expert but I do hang out at with my friends a lot and they all have their own reasons for doing it their way. Don't spend a lot of time worring about the best way to do it. Use the tooling that you have access too and try to spen more time at the range than behind the lathe.

Earl

notised you are from arizona i only now of one Lester there and he is a top hall of fame shooter (the other names sounds strangle familiary to LOL)
i got a floating reamer pusher ( i build buit not tested yet see project of the day forum pg 75 )
i got a older lathe http://www.lathes.co.uk/mondial/page2.html
got a spider on the back of my headstock ,got a front indipendant 4 jaw ore spider setup the lathe is long enuf so i can chose bought methodes headstock/steady rest
the only thing missing for now is some pilot bushings for my jgs reamer

 

[chuckorlando]

Do these reamers actually float or do they pivot? If it floats I would think it would be able to travel straight within the available movement. Provided it started straight. If it pivots I would think your creating a triangle to which your ream becomes the hypotinuse and enters at an angle. That would put the front to one extreme and the rear to the other creating an egg.

I have no experience here just been thinking about this from the first post. Figured I would toss it out and get some perspective.

 

[dave2176]

Do these reamers actually float or do they pivot? If it floats I would think it would be able to travel straight within the available movement. Provided it started straight. If it pivots I would think your creating a triangle to which your ream becomes the hypotinuse and enters at an angle. That would put the front to one extreme and the rear to the other creating an egg.

I have no experience here just been thinking about this from the first post. Figured I would toss it out and get some perspective.

The holder floats, not the reamer. It allows for the tailstock to be off a bit. Some reamers have a live pilot so they don't spin in the rifling. But yes if not lined up sufficiently you could make the reamer the hypotenuse and taper the chamber.
Dave

 

[Tozguy]

JT, nice work on the reamer holder.
Just wondering how you plan to clear chips from the reamer.
Also, how does the pilot already on the reamer fit the bore?
It seems to me that the type of rifling in the barrel is an important consideration when fitting a pilot and choosing a technique. Some types of rifling are more likely to be deformed by the pilot than others. For instance, narrow lands and/or 4 lands would have the less surface contact with the pilot than 6 wide lands would.
That is the main reason why I would not rely solely on the pilot to align the reamer with the bore. Considering the design of your reamer holder-pusher, I don't see how you can avoid preboring the chamber to get enough control on the reamer.

 

[JT.]

JT, nice work on the reamer holder.
Just wondering how you plan to clear chips from the reamer.
Also, how does the pilot already on the reamer fit the bore?
It seems to me that the type of rifling in the barrel is an important consideration when fitting a pilot and choosing a technique. Some types of rifling are more likely to be deformed by the pilot than others. For instance, narrow lands and/or 4 lands would have the less surface contact with the pilot than 6 wide lands would.

That is the main reason why I would not rely solely on the pilot to align the reamer with the bore. Considering the design of your reamer holder-pusher, I don't see how you can avoid preboring the chamber to get enough control on the reamer.

I probably will prebore the hole wit a boring bar I got Kriegers with 4 lands so I think that is the best way
the pilot on the reamer is standard seems to be a .3640 (will have a set of pilots next week ore so )
I got travel enuff on my rear rest to get the reamer completely out the hole (6ppc is not so long )I got about 6-7 " of travel
I got a long WE in 2 weeks so that will be the real test for me

 

[Earl]

In my opinion there are few shooters, if any, who can evaluate a chamber job with a target.

Most competitive shooters can evaluate their shooting systems very well. They have the finest shooting equipment available in the private sector. Custom Actions, Triggers, stocks, scopes, bullets and barrels. When you have such a system and change one component (like a freshly chambered barrel) you can imediately tell if is good enough to be competitive. If it doesn't shoot up to your expections, you screw on a "known good barrel" and compare the results. You cut off the chamber and re-do it, cut a new crown and try it again. If it still doesn't shoot competitively It is usually relegated to a corner somewhere. Some might ask "what does shooting competitively mean?" I recently returned from a match where I shot a 10 shot group at 100 yards that measured 0.189 inches (one hundred eighty nine thousands of an inch ) larger that a bullet. I didn't even make the top 10 for that relay!

 

[Tozguy]

Earl,

My comment was not intended as a slight to competitive shooters. I compete in bench rest enough to know how many variables are involved in shooting a good target. It gives me tremendous respect for those who shoot in the ones consistently let alone in the zeros.

My comment does not relate to their ability to evaluate a barrel. It relates specifically to what a target can tell us about the quality of a chamber job. It would be a surprise for me to learn that someone can look at a target and end up saying ‘’ ah yes the chamber job is bad on this barrel’’. As you implied, when a new barrel doesn’t shoot to expectations there are several factors to consider. Isn’t that why we can say that a good chamber job is no guarantee that the gun will shoot? If a new barrel doesn’t shoot and gets put aside, isn’t the next barrel chambered in exactly the same way?

Cutting a chamber (and cutting a crown ) is a machining operation that can be done reliably and checked for precision before it leaves the shop. It can be done and done well by a machinist who understands the objective of the operation but who has never pulled a trigger.

Some top competitors who do their own smithing accomplish amazing results at the range. However, there is ample evidence that one can be a top gunsmith without being a competitor. If someone is passionate about learning to cut chambers properly, which I think is what this thread is about, it can be done without having to win the Super Shoot first.

With respect, Mike

 

[JT.]

winning the SS with gear you made yourself must give 10x more satifaction
i may not be a great shooter like the real pros but my 4th place years ago(for once everything feld good ) in the 200 HV and in the running to win the 200 LV (till i fel of the bench the last shot of the SS and ended 20 th ore so) with a barrel chambered by a friend ,i tought immidiatly "what a great barrel job ". made my own stocks and bullets ,home made frontrest the next logic step is doing my own chamber job .some time i am maniac on a thing and i can get in to it real deep and this is gooing that direction i will go for so close as i can get to perfection just to now i dit the best job i can do