Anyone ever do chamber resizing?

Simmer down · Feb 2, 2013

I got a set of pin gages and found I have some variations in the cylinders of my 21-4s (.427-.429). It looks like I can use a finisher reamer to put them all at .429 or use a lapping set up Through-Hole Laps | MSCDirect.com to cautiously compound the smaller throats up to .429

Any voices of experience regarding ease, difficulty, or what not?

tomcatt51 · Feb 3, 2013

Simmer down said:
Any voices of experience regarding ease, difficulty, or what not?

Pretty easy to do. Too small throats are not good for accuracy. I'd say reaming is best.
REVOLVER CYLINDER THROATING REAMER | Brownells
Select the correct size pilot. Trim the base off a fired case, leaving just a "sleeve" to put in the chamber to help center the reamer. Use the thick brown nasty cutting oil. Turn the reamer by hand.

garbler · Feb 3, 2013

Most of the better shops use a honing machine like a Sunnen for this work. It leaves a better finish with more control than a reamer. You can ream if careful but you still need to come in and polish. I know Hamilton Bowen does a lot of this work and he uses a honing machine to open up chamber throats and polish. At one time he was cleaning up a lot of Ruger Vaquero's with undersized chamber throats that nobody could shoot since the bullets were being swaged down before they could get into the barrel leads.

Pachmayr's shop years ago had a number or various honing machines set up with various indexing fixtures for cylinders when he was doing match guns. I have some old photos of the shop floor from back in the early 60's showing this operation.

Simmer down · Feb 3, 2013

I have about 6 guns needing this sort of work so I'm weighing DIY vs writing a check.

tomcatt51 · Feb 3, 2013

garbler said:
Most of the better shops use a honing machine like a Sunnen for this work. It leaves a better finish with more control than a reamer.

"leaves a better finish" Are you speaking from "hands on" experience? If you're doing volume and have a Sunnen set up already they work well and it's quick. Hand reaming (most of us don't have a Sunnen hone) is more tedious. You match the pilot to the existing throat size, put the sleeve in the chamber, then ream. The results can be very good as is the surface finish.

When you're removing realtively small amounts of metal I think the reamer will "straighten" an "out of round" (very common) throat better than honing.

The reamed vs honed surface finish will look different but I doubt you can find any functional difference.

tomcatt51 · Feb 3, 2013

Simmer down said:
I have about 6 guns needing this sort of work so I'm weighing DIY vs writing a check.

Understandable. I don't know what kind of hands on skills you have, or if you know someone who does who you could have run the reamers. But, ~$130 for a reamer and pilots spread over 6 cylinders, I think is attractive.

garbler · Feb 3, 2013

tomcatt51 said:
"leaves a better finish" Are you speaking from "hands on" experience? If you're doing volume and have a Sunnen set up already they work well and it's quick. Hand reaming (most of us don't have a Sunnen hone) is more tedious. You match the pilot to the existing throat size, put the sleeve in the chamber, then ream. The results can be very good as is the surface finish.

When you're removing realtively small amounts of metal I think the reamer will "straighten" an "out of round" (very common) throat better than honing.

The reamed vs honed surface finish will look different but I doubt you can find any functional difference.

Of course you can hand ream a cylinder with a good reamer of the right design and pilot I have done it on many older revolvers and even re-lined a couple of rimfires years ago. I only mentioned the hone for reference and I certainly understand nobody is going to go out and buy such a machine for a couple of jobs. It's just that I spent some time with Hamilton Bowen years ago and knew a few guys who built match revolvers at Pachmayr and thought it was interesting that they used a honing machine to fine tune cylinders. Bowen is not what I would call a production shop so his choice of using a honing machine is based entirely on repeatable accuracy and performance.

While on this subject it is amazing how many revolvers and firearms in general leave a factory with chambers all over the place due to running worn or dull reamers. If they meet Saami spec they ship regardless of the difference between barrel spec and cylinder specs. You can get away with it on a match grade rifle since tighter chambering is usually best but a tight chamber mouth in the revolver usually means miserable accuracy. I have a lot of guns that had one of two chambers that would not group and with bullseye shooting you just leave that chamber open since you only need five anyway. Eventually the offender gets reamed and the problem goes away mostly otherwise the gun goes away

Regards

tomcatt51 · Feb 3, 2013

garbler said:
While on this subject it is amazing how many revolvers and firearms in general leave a factory with chambers all over the place due to running worn or dull reamers.

Agreed. I've accumulated chamber reamers just because of this. Just for revolvers. I have, .45acp, 38 spec, .357 mag, .22LR, and for S&W 41 chambers because of friends who have them. Since "Cylindersmith" stopped reaming throats other than .45 I'll be accumulating more throat reamers as need warrants.

I do (personally) have a 3" 10-8 HB that my saami spec .38 chamber reamer literally rattles around in. Same for a friends 625-3, may have been a recall gun. There do seem to be exceptions.

Simmer down · Feb 25, 2013

I got a 44 mag Clymer reamer and did my 29-2 with great results.
This is SA one-handed at 10 yards. I used to always get a least one flyer. Considering the variance in the throats that was likely the best I would ever get.

jepp2 · Feb 25, 2013

I have done 3 of my revolvers with .32 cylinders with a reamer I bought from Manson. Straightforward to do.

Another option is to rent the reamer from 4D Reamer Rental for a lower cost option if you don't want to purchase the reamer. I haven't rented from them so I don't know what condition the reamers are in.

I preferred to be the first to use a new one and thought I could always sell it afterwards if I didn't need it any longer.

Anyone ever do chamber resizing?

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