Chambering without a reamer?

Bill Lunbom · Nov 12, 2006

I'm going to display my ignorance for all to see. Is it really necessary to use a reamer? Seems like a fellow could do the deed with a boring bar. Set the compund at the correct angle and stop at the measured depth. Am I missing something here?

deltaenterprizes · Nov 12, 2006

the finish would be kind of lacking,dimensions not as close as necessary,and repeatability would be tedious

Dave Haven · Nov 12, 2006

It would be a serious challenge with a bottleneck case.
I did sleeve a 9mm Parabellum chamber on a submachine gun a few years ago and re-cut the chamber with a boring bar because I didn't have a 9mm Parabellum chamber reamer. It worked - went ratta-tat-tat when test fired..

Chamber reamer is a LOT easier.

kilroyjones · Nov 12, 2006

If you are planning to chamber a barrel and don't want to buy a reamer read below. If you were just asking if it could be done, ignore my post

There are companys on the internet that rent chamber reamers. Can't come up with a name right off the top of my head, but a search should find it.

willbird · Nov 13, 2006

The chamber itself is probably the least problematic, cutting a proper THROAT with a boring bar would be the real challenge

. I think your time would be better spend MAKING a remaer, which some of the older guys have done, and they tell me it will make just as good a chamber as a boughten reamer, the ones they made are called "D reamers"..they have only one cutting lip.

Bill

GGaskill · Nov 13, 2006

It would be practical with a CNC lathe but with most bottleneck cases, you would have a body angle, a shoulder angle and a throat angle that are all different which would make it a challenge not worth the trouble with a manual lathe. Plus the reamer gets the diameters right at the same time.

PCali · Nov 14, 2006

I've got an article in a book someplace about cutting chambers (and loading dies) using a boring bar...
Yes, it can be done... a couple dial indicators, a good SHARP tool, lots of cuttting oil.. and patience.
Throat with a reamer.

I have also made a "D" reamer to make a loading die.
Turn the profile on a piece of drill rod.
Harden.
Polish.
Grind away exactly HALF of the profile except for the pilot.
Use a hand stone to slightly relieve behind the cutting edge around the circumfrence.
Lot of work, but the reamer I made did cut a couple dies, and the finish was good enough that I could have cut a chamber.
The reamer wore too quickly to do a third though... but that was almost certainly from grinding and allowing it to overheat (softening it a bit more than I shoulda).

A CNC lathe would be great for this kind of work. Both for profiling a reamer, and for boring a chamber.

In my opinion...
Paul F.

RobbieBeggar · Nov 16, 2006

If you have a good grinding setup, you can modify the regular reamers to work as chamber reamers. Rimmed rounds are much easier as headspacing is much simpler. I've done 9mm, 10mm and 7.62x45R like this.

jabezkin · Nov 18, 2006

One thing about boring a chamber. location is correct. Using a reamer for geometry is correct, so bore to locate, and let the reamer start inside your bored hole, thats one of the reasons God tapered cases. Good Luck and God Bless

RayO · Nov 21, 2006

Wolfe Publishing has a book called "Gunsmithing Tips & Projects" that has an article on how to cut chambers using boring bars.

failsafe7 · Nov 22, 2006

Elk Ridge, I believe used to be Buck Steele's. (that's the name that I remember, anyway) This was the cat's ass for reamer rentals at one time. Coincidentally enough, they are at http://www.reamerrentals.com/

You can also rent at 4-D. - http://4-dproducts.com/

KenS · Nov 26, 2006

I've rented reamers from Elk Ridge (www.reamerrentals.com/) a bunch of times. They're fast and don't count the time in the mail as part of the time you have it. They've always been sharp.

The downside I see to chambering with a boring setup would be the time it takes and the risk of a ruined barrel.

I don't think doing a straightwall revolver chamber would present many problems and would likely do it if it ever came up.

jabezkin · Nov 26, 2006

KenS
Ah, well, straight wall revolver chambers aren't and won't do if it ever comes up. Trust me, I'm not jumping on you but it could ruin someones project.

Clark · Nov 28, 2006

There are articles in old gunsmithing books about making bottle neck chamebrs with boring bars.

I tried it with a 452" groove 45/70 and did not get good groups at the range.

I have make great 9x23mm chambers with drills.

I have made 45acp chambers with a .479" reamer and a thoater, that works very well for a bolt rifle.

The Shilen told Bryant that he:
1) Drills to remove metal
2) Boring bar to get hole concentric
3) reamer to get final shape

He does this to reduce the wear and tear and the reamer.

I have made the forcing cone for shotgun chokes with the boring bar. THey are about 1/2 degree.

jabezkin · Nov 28, 2006

Clark,
I have bored chambers but for higher pressure rounds, finish and that little bit of taper is the difference between brass dropping out at 60000cups or wondering just how strong that ejector rod really is. In a 5 shot 45, one brand of brass is good for one reload, another maybe 5, and good ol federal, 60000 cups and we dont care. As the pressure goes up, I try to eliminate as many variables as I can. I like to"chop" my cylinders with an end mill, flutes releived, to save the reamer. I never do use an official roughing reamer, just chop to near size, and chamber. What bolt gun did you put the 45 ACP in ?

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Chambering without a reamer?

Bill Lunbom

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willbird

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RayO

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