Enlarging revolver chambers to groove diameter

[phoenix511]

Anyone done any before-and-after accuracy testing on enlarging the chamber on a BP revolver to the barrel's groove diameter?

There are several good Forum threads (search for "enlarge chamber" in the Handgun topic) that deal with how to enlarge the chamber and to what size as it seems nearly all Italian replica have chambers somewhat less than groove diameter.

I'm interested in what the original dimensions were and how much did accuracy change after enlarging the chambers.

I have two Rem 1858 Pietta's, where the chamber is only 0.002" less than groove diameter (maybe NOT a candidate to enlarge), and a Euroarms Rem 1858 that has chambers that are bore diameter (probably a candidate for enlarging).

 

[kwilfong]

I can't quote specific group sizes, but I have seen groups tighten up after reaming the chambers. I've done 3 Pietta Remingtons & a Pietta 1860 Army, all to .453" to go with .452" groove dia., just today did a Euroarms Remington to .449" to work with the .448" groove dia.

 

[hawkeye2]

"I have two Rem 1858 Pietta's, where the chamber is only 0.002" less than groove diameter (maybe NOT a candidate to enlarge),"

These are the ones you NEED to ream! I have all mine reamed to .456" and use a .457" ball. Actually I would ream the other one too. Cut a new gentler forcing cone while you are at it.

 

[wulf]

Because the rifling is so shallow, I reamed all
my 36's to 380. Greatly improved accuracy and
hitting power...two 1836's, 1851 and 1862.Nipple
pressure increases and hammer blow back is
possible.
Wulf

 

[CoyoteJoe]

I had a new Euroarms Remington .44 which, out of the box, threw nothing that could be called a group. I found that if I rammed a ball into a chamber and pushed it back out with a rod through the nipple hole it would actually fall through the barrel. I reamed the chambers and immediatly began shooting one inch groups at 25 yards.

 

[Stophel]

Is this something you all are doing with a hand held reamer, or sending off to someone to do for you?

 

[D Sanders]

Had an ASM Colt Walker,.007 under groove dia. Reamed out to .001 under. Made a huge improvement in groups.

HH 60

 

[kwilfong]

I wouldn't recommend doing it by hand. I chuck a pin guage that's snug in the existing chamber in the spindle on the mill & use it to line up the cylinder in the vise on the mill table, then replace the pin guage with the reamer & have at it at the lowest rpm, then repeat for the rest of the chambers.
If any of you boys don't have the facilities for this,& would like to try it, I could be talked into it :hmm: I have reamers in .449", .452", & .453" Other sizes would require a new reamer @ $30-$60 a pop.

 

[kwilfong]

What tooling are you using to rework the forcing cones? Seems like Brownell's has something for that but I haven't tried it.

 

[Norinco]

Pipe deburring tool?

 

[kwilfong]

Don't think I'll try that on any of mine. Too much chance for chatter & not sure what the proper angle is.

 

[CoyoteJoe]

Is this something you all are doing with a hand held reamer, or sending off to someone to do for you?

I've done several by hand and have no complaint with the results.

 

[Stophel]

Where are the reamers available from? I would have figured that since you are only reaming out a TINY amount (like one or two thousandths) that it shouldn't be too difficult to do without a milling machine.

 

[CoyoteJoe]

Online from ENCO, 29/64ths = .453" I'm sure there are other sources and sizes but that one works for .44 revolvers using .457" balls.

 

[kwilfong]

I just bought a .449" & .452" from MSC Ind. Supply. I use the mill because I have it & it keeps everything straight. Looks like it can be done by hand if you're careful.

 

[hawkeye2]

A Brownell's kit I bought 15 or more years ago. I only bought the .38/.45 kit and wish I had got the whole thing with .22 & .32 tooling.

 

[brentp]

How much more complecated is it to ream out stainless steel cylinders?

 

[Norinco]

Should be the same process, unless you have a crappy reamer.

 

[kwilfong]

I'd be sure to have a fresh, sharp reamer & turn it slow with plenty of cutting oil. I've been using 80 RPM on the Bridgeport. The stainless used on barrels & cylinders isn't all that hard but it's tough & "stringy'.

 

[kwilfong]

A Brownell's kit I bought 15 or more years ago. I only bought the .38/.45 kit and wish I had got the whole thing with .22 & .32 tooling.

Thanks for the input! I'll have a look at those. I have several C&B's that could benefit, + I've been doing some work on a 45 Blackhawk Convertible. :thumbsup: