Anyone cut a chamber in a barrel without a reamer? By that, I mean just cut a chamber on the lathe with a tool.

Seems like with some basic cases like a 45-70 (straight case, rimmed) that this would be a fairly straightforward task.

I have a wildcat idea I want to play with but don't want to mess around having custom reamers ground.

Sam B.
http://www.fireflyarms.com

Sam,

Yes sir you can cut a chamber without a reamer, but I would imagine it not to be too easy.

All depends how good you are on the lathe, and how good your lathe is.

Hi Sam,

This might help answer some of your questions?:
http://www.nookhill.com/ubb/ultimatebb.php?ubb=get_topic;f=5;t=002616#000019

Regards, Bill

SamB,

There you go, perfect example of archieved information. Do a search regarding "half round reamers" We had a discussion a while back on how to make one of a kind reamers for test jobs. making up a half round reamer would be a lot less frustrating than trying to cut a chamber using a boring bar and the lathes compound feed. Been there, done that. Successful? Yes, care to repeat it? No...

Good luck,

Malm

Sam,

A Half-reamer may also suit your needs?:
http://www.nookhill.com/ubb/ultimatebb.php?ubb=get_topic;f=5;t=005367#000000

Then you don't have to mess with solid carbide boring-bars (to reduce deflection), CNC lathes, etc., that may be required for chamber boring with a single-point cutting tool.

Regards, Bill

Case Hardened Corn Cob Reamers. Shape the cob with sandpaper, then fire harden in the campfire.

On a more serious tone, I highly advise using a proper reamer for any chambering job, especially if the goal is a "Standard SAAMI Chamber" and the rifle may in the future fall in the hands of another person. Even Wildcats benefit from a real reamer. Chamber surface finish is very important, and dimensional tolerances are extremely important both for safety and ease of extraction.

Many years ago when I was sure I knew everything I worked in a well equipped tool and die shop with all the fancy lathes, mills and grinders. I made a chamber reamer, with flutes, the standard way. After this one time experience I learned to send money to a professional reamer grinder, it is a whole bunch cheaper and you get a better product.

What is your Wildcat? Chances are it has been done before.

With all due respects friends, it's possible to bore a chamber instead of reaming it.

It's all in the way you hold your cards.

I have researched this just a bit.There is tooling avaliable,commonly referred to as "micro tooling" that will do this,within reason.Anything from .375 bore and up wouldn't be that hard(you can fit a bigger boring bar into the bore),depending,of course on how long the chamber is.A solid carbide bar combined with a good CNC machine(small chuck,high RPM and a very rigid spindle)and you could give it a try.Try it before I do...please.

Having only ran a mere few thousand parts on CNC lathes, the answer is most definitely, YES.

Here would be your limitations:
1)diameter of neck(anything under .308 caliber is going to be extremely difficult.

2)Length of cartridge(any cartridge over .308 length is going to be nasty to hold tolerance.

3)Inspection and qualification of the machined surfaces.

About the best cartridges going for this kind of operation would be the WSM's or WSSM's.
Surface finishes and tolearances on those particular cartridges would rival any reamer in existence. The best scenario would be probably the .375 WSM.

Boring bars for doing this kind of work are pretty much off the shelf if you know where to look. There really not that special.
Solid carbide would be undoubtly in order as well as having through coolant capabilities as well.

Most likely you would rough the operation out with an endmill before tackling the finish op with the boring bar.

But, with all that said, it is more than feasible, and could produce quite desirable results. You just better figure on getting your own CNC before you start. This is not a job for the manual lathe, by any means.

I know a Gent that shoots 1000yd BR and he does his "own" chambers and dies on a CNC him and his brother have in their shop, a very expensive one. He said it's friggin scarry it cuts so damn FAST too! The last one was a 30, short mag length, but based on the 416 Rigby case.

Well, yes, anything can be done, but when you run the bottom line costs associated with making half reamers, trying to bore with a boring bar on a manual lathe, etc., it ain't cost effective IF one is making a living chambering barrels and building rifles. If anyone really wants to see it, I have a nice article written some 25 years ago about cutting chambers in a manual lathe with boring bars and dial indicators set up to measure what you are doing.

I would venture to guess few of us have the proper CNC lathe and the programming experience to bore chambers. If you do, then you are fortunate.

For one-off work, or something for the home project category, sure, have at it. But when safety is involved and once the rifle leaves your hands you have no idea of who uses it or what they will stuff in the chamber, the it is reamers made by a professional reamer grinder for me.

One key for me is repeatabiilty. I want the 416 Ultra chamber I put in a rifle today to be the same as the one I put in a rifle 5 years from now.

The rules change when one progresses out of hobby gun work to a business.

As I read the original question, no where do I see any reference to "hobby or business" much less anything regarding "repeatability". I see an uncomplicated, very simple question asking if a chamber like 45-70 can be cut without a reamer, and the straight, "No Bullshit" answer is "YES" period.

It wouldn't matter if a person were wanting to do an experimental project, requiring a specially dimensioned chamber, as a hobby, or as a professional development project, the answer is the same, "YES" it can be done.


Regards,

Malm

For completeness only, but there are a number of factories that hammer forge their barrels AND chambers at the same time. FWIW, Dutch.

Thanks for the insight folks. Seemed possible and I'm glad to hear it has been done successfully.

This is a one-off project for fun. A short .50 along the lines of a 500 Whisper, 50/110, etc. I don't doubt it has been done before, but as I said, it's just for fun.

Thanks again,

Sam B.
http://www.fireflyarms.com