Hi Folks. How difficult is it to lathe cut a rifle barrel chamber?

are we assuming we have a chamber reamer?

No, I don't. Sorry, I should have been clearer. I'm talking here of making the tool/tools and turning the chamber. (I do have the instructions on how to make a reamer but that looks pretty time consuming too - and is something I have not done before so it could include a trial run or two).

Oh, I would turn a set of sizer dies at the same time.

quote:

I'm talking here of making the tool/tools and turning the chamber.

Maybe someone else here can do it.....it's much cheaper for me to buy a reamer and then resell it....This don't get you the sizing die however...

I'm not a gunsmith but am betting that time and materials wise you are better off just renting or buying a reamer.

Red

You think making a reamer looks time consuming? Cutting a chamber with a boring bar is not exactly a walk in the park. You would probably do better to use 3 different size drill bits. One for the body, one for the neck and one for the throat. If it's going to be a belted magnum, then it will take 4.

I know of a couple of crackerjack CNC people and their attempts were less than successful. Can you imagine a boring bar that hangs out 2.25" and is small enough to do the neck and throat of a .243. The bore size of a 6mm is approx .236". This is for a short 6BR.
I don't think so even with a solid carbide boring bar.
Butch

There is a chapter in Gunsmithing Tips and Projects about cutting a chamber with a lathe and boring bar. The author said 30 caliber is as small as he would go. He used a taper attachment to cut the body taper and the compound to cut the shoulder angle in one setup. Obviously it depends on the chamber. A 45-70 would be fairly easy.

It is pretty easy to make your own reamers, IF you are making "spade reamers". They make pretty darned nice smooth cuts, too. Many of the old time gunsmiths used them.

The subject has been discussed in detail here before, so it's probably easiest to search "spade reamers" here, then go to google and search it again.

Basically it entails cutting the shape you want on the lathe, then filing away almost half of it. Makes a good, strong, single-fluted reamer.

Building a spade reamer is the way to go if you just really want to. I would rather buy a reamer and yes they can be sent to NZ.
Butch

Spade reamers are also called "half reamers". As Canuck said, many of the old timers used them. I have made a few myself for one-shot jobs and you can make one in a couple of hours at most.

I have tried boring a chamber, and it ain't fun. The body and neck are easy enough but boring the shoulder requires a bunch of light cuts and everything has to be set back to "zero" between cuts. One little misstep and you can ruin the whole thing. I've found it easier to make a 1/2 reamer just for the shoulder.

But, as Butch said, buying a reamer is probably cheaper in the long run. Unless your time is worth nothing.

Ray

You might have success looking for discussions of "D" reamers.

I think those that have ever made their own will be the first to encourage you to use a properly made commercial multifluted reamer. I would consider making another only if it were for a short rimfire round, and then only as a last resort. It is possible to do this and make an acceptable chamber, but this type of work has a very long learning curve. Many things can and do go wrong. You need a good lathe, a good surface grinder, and a good heat oven. For my money, reamers are a bargain.

I love to make my own tooling, and do so as often as I have time, but I am just not rich enough to put the time and money necessary into making reamers. Good Luck! Let us know if you are successful.

Roger

This goes back a few years. Lucky the info is still in print.

https://forums.accuratereloading.com/eve/forums/a/tpc/f/...?r=71810864#71810864

https://forums.accuratereloading.com/eve/forums/a/tpc/f/...?r=34510964#34510964

Boring a chamber is not so difficult for some configurations. Large bore straight or straight taper chambers can be cut pretty easily especially if not too deep.
Plan well, have patience and take it slow. Even then you may still need a throat reamer.
A taper attachment helps if the chamber has a taper.

Thanks for all the input Folks. This sounds like a fun challenge! Yup, I want to try this just because I can. One day I want to take a rusted/shot-out 303 barrel and rebore and re-rifle it to 357/303. But for now, I want to cut a chamber. I did not know about the spade reamers. I had the idea I would have to do it in three steps and that a 30 caliber would be the smallest reasonable bore to do but, it is a 257-303 wildcat I am after. Well, If I can make a chamber to properly fit the 257 Roberts then that is what I will do.

Today I turned a drill bit into a bullet mold reamer and cut a 215gr hollow point bullet mould, shaped like a Norma 311 bullet. (I am about to cast my first bullet!)

quote:

Originally posted by 303Guy:
Thanks for all the input Folks. This sounds like a fun challenge! Yup, I want to try this just because I can. Today I turned a drill bit into a bullet mold reamer and cut a 215gr hollow point bullet mould, shaped like a Norma 311 bullet. (I am about to cast my first bullet!)

Good On Ya, .303Guy!!! In the long run, making your own reamers and other tools, and learning how to do every kind of work is the least expensive way there is to go, even if you were a Billionaire and got $10,000/hour selling your time as a consultant.

How's that? Because you will be self sufficient in one more respect. There are times (and I've seen one of them in my lifetime) when no amount of money can get you what you desperately need, and making/doing it yourself is the only way to get it.

If you have the knowledge and experience, you'll be okay but those who didn't want to "waste their valuable time" learning how to do it will be up the proverbial creek with no paddles but their tongues.

I hope I'm wrong on this, but it looks as if a Third World War may be approaching more and more quickly. If so, we're probably all up a creek, but some at least will survive. How well they do during & afterwards depends on what they can do for themselves (and a whole lot of good luck).

My dad's skills (which he passed on to us kids) proved that during the last World War. We made our own shoes and clothes, raised, harvested, preserved and prepared our own food, repaired our own machines, and so on. So, we lived a bit better than many of those around us.

Some of them from the shallow end of the gene pool didn't fare easily at all.

If nothing else, having the knowledge and ability is fun, as you already appear to know.


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Thanks for that Alberta Canuck. (I hope you are wrong about the third world war! Sadly, you could be right).

I get most of my entertainment from doing and learning new stuff. I got my first successful cast bullet today. I have devised (but not built) a system for casting. The lead goes in through the nose end and comes out the base end. The 'sprue cutter' is actually the hollow point punch. Once the temperatures are correct, a cavity free and well formed bullet is produced. This then goes through a sizer to remove the taper from the shank an presto! The chamber reamer is coming up soon but before that is going to be a scope mount with range adjustment. (So many projects and so little time ).

quote:

Originally posted by 303Guy:
Thanks for that Alberta Canuck. but before that is going to be a scope mount with range adjustment. (So many projects and so little time ).

First off, you are quite welcome. Relatively young guys like you who enjoy learning and doing are the true "salt of the earth" in my view.

I'm quite interested in your adjustable mount project. Which approach do you plan to use?

I still prefer the old Stith "Master Mount" on my hunting-use Mausers, Winchester bolt actions, and Savage lever guns. Are you familiar with that mount? It is adjustable for both windage and elevation with a simple allen wrench. It could be better, though. Would be really great if a guy made one with "click" adjustments. It never came that way, but I feel should have.

The one I liked the least was the early Leupold Adjusto-Mount. B&L's (and their clones, Kuharskys, were okay for adjusting, but none-too-secure overall for keeping the scope securely on the rifle. At least those were my experiences.

quote:

... Stith "Master Mount"

No, I have not heard of it. Well, I might have but not the name.
I have had several ideas on how to do this, so far spring loaded sliding faces are on my mind. The idea then is to have a 'jacking screw' hand wheel (also spring loaded) to raise and lower the scope. No windage! The idea is to adjust for range only and to zero the scope in the 'at rest' position with calibrations as determined in the field. The thread pitch and pivot spacing will be chosen to give 1/4 MOA per turn adjustment. The whole thing is still in my head. (But the action is in the jig, ready for the mill).

Edited to add; I have come up with a system which relies on a taper pin in the front mount with a nylok nut on each side to pull the taper pin in firmly on the one side and to hold the other side firmly against the vertical mounting block. When I have drawn it up in CAD, I could post you the drawing.

Would be very interested in seeing the drawing when you have it worked out.

In the meantime, hope I'll get the chance to look through some of the thousands of documentary items I have from the old days...in there somewhere, I know I still have both a set of instructions , pictures, and line sketches of the Stith Master Mount. If I can find them I'll let you know. Then, if you send me a mailing address, I'll send copies to you for your info.

If not I'll have to take pictures of the ones I still have on some of my hunting rifles and send those to you.

The Stith MM used cones somewhat similar to the B&L mounts in principle, fore and aft, but they were screw adjustable and lockable (which the B&Ls were not) so that NO-ONE could move them without an Allen wrench...a real good idea both at matches and in hunting camps. Some people just seem to have irrepressible urges to screw with other people's sights. Of course no one would use them in matches these days, but they sure are nice in hunting camps...they're about as sturdy as one might envision a titanium anvil to be.

Likewise the Stiths were all-steel, and had two piece bases...that is one base forward and another aft, rather than one piece bases like the B&Ls.

The one thing I would caution you against is using a single verticle screw of anything smaller than at least 3/8" diameter as the single support for your elevation. Both Buehler and Leupold tried that and it never really worked out well for either in my opinion.

As far as a useful windage adjustment, either the cone methods used by B&L and Stith worked fine, but so does something as simple as the opposed screws in a Redfield Jr. base. Would work better, though, if one used one beefy screw which went all the way through a threaded hole in the bottom of the rear ring, thus both moving the rear ring sideways into alignment with the bore & target, AND holding it securely down at the same time.

Envision the lateral movement arrangement of the eyepiece on a Redfield Inernational rear sight, then scale it up to hold a scope ring rather than an eyepiece reticle. And of course, mount it directly to a base, or better yet, let it BE the base mounted directly to the rear reciever ring of the rifle. You'd have to make a rear scope ring to fit, too, but that's a simple trick.

Good luck, and if you can post pictures here, please let us all see it/them when you get done.

Best wishes,

AC

Thank you kindly Alberta Canuck. I'll PM you my mail address.

P.S. I have just found an ideal material for making scope mount bases. Alloy bicycle crank arms.

Take a look at the base to ring adjustment and mating of the scope mounts used on the Russian Nagants. They are bullet proof and adjustable too.
I would like to try adapting it concept to a top mount design.