Color change in a blued cylinder

[mojave30cal]

What would cause the blued finish on a 1950 38/44 transitional
cylinder to turn a "plumb" color? This HE is chambered in .45 Colt with a blue 4 inch barrel and a pinned half moon front
sight. Looks like the barrel was cut back from a 5" or 6" bbl.
and re-blued and re-case hardened. Sort of a "Franken gun".

Any thoughts??

 

[flundertaker]

Time.
Seriously I dont know the chemical process but since Bluing is technically a form of "rusting" I would bet that the plumb color is a continuation of that process over a long period of time. I have seen many old SA Rugers that have this on them. I actually like it the way it looks. Sort of the BTDT look.

 

[Skeetr57]

The color difference is probably due to different steel alloys or different heat treatment of the cylinder and frame. You don't see this effect with rust blued guns or the older carbonia blued ones, just the ones done by the modern caustic hot blue. I have read that the two tone look can be avoided by placing the parts in the bluing tank at a reduced temperature before raisig the temperature to the desired stage.

 

[Modified]

Most of the time I've seen this happen on old smiths it was pretty clearly on a re-blue. I don't know if that is the case here, but in my (admittedly limited) experience that has been the case.

Although I have seen some guns that did have a slight difference between cylinder and frame, I would never have called it Plumb like I would old rugers or dan wessons.

 

[Texas Star]

This is one reason wny I now buy mostly stainless guns.

I've seen it a lot on Ruger blued single actions, not so much on their DA guns. Had it happen to the receiver of a Sako Finnbear rifle.

 

[bgrafsr]

Re-blued Winchester receivers are also known to turn plum colored.

 

[153]

Lot's of guns turn plumb. Sometimes it happens overnight and other times it takes years to show up. Not much you can do about it, unless you use another bluing method besides the common caustic blue. I've tried all the methods, including soaking the parts in ice before and after the tank ... nothing worked.

I've heard Winchester used to "iron plate" '94 receivers before bluing them. They had a lot of trouble because of the alloy used in the post '64 .30-30. But I could never find anyone who plated with "iron" so that may be an "old wives tale."

 

[dlidster]

I have a very nice M&P from the early to mid-thirties (6275xx) that is not a reblue that has a plum-colored cylinder. I find it both interesting and attractive. I have a K-22 Outdoorsman that's just a bit newer (6574xx) with a cylinder without a trace of the plum color. But . . . my S-prefix transitional M&P (S 9528xx) appears plum-colored in bright sunlight.

FWIW, my Ruger No. 1S receiver made in 1984 is plum-colored, while the receiver on my No. 1V made in 2000 has nary a trace.

The photo is of my early M&P.

Addition: On a rifle I built on a Mexican Mauser action back in 1959, my gunsmith deliberately made the bolt shroud plum-colored by "bluing" it in salts at a higher temperature than normally used to truly blue the metal. (For the sake of others here as old as I am who lived in the Chicago area, I'm referring to Paul Haberly at the Chicago Gun Center.)

 

[mojave30cal]

This revolver I'm referring to looks like a transitional 38/44
with a serial # 75XXX thereabouts. It has a 4 inch barrel marked 45 Colt ctg., and the half moon front sights are pinned
to the top of the barrel. The hammer and trigger look like they
had a recent re-case hardening, and the over finish looks like
it was re-blued. Only the cylinder is plum color. I couldn't find
this revolver any where in the SCSW catalog, so it must have
been re-done in the .45 Colt caliber sometime in the past. It's
a "Frakengun" if you will.

 

[Texas Star]

I've heard that Ruger's problem is their steel alloys coupled with silicone in their molds.
But unless the steels used in their DA guns are different than Blackhawk guns, it's probably just coincidence that I haven't seen plum-colored Ruger DA revolvers. I only buy stainless handguns now, anyway, and have seen no issues in either Ruger or S&W stainless guns.

But I have seen many WW II guns that had plum-coloring and some Colt Govt. Model .45 and Woodsman pistols from the 1950's and later. A gunsmith told me the problem is from not having fresh bluing solutions and having the salts at the right temperature. I can see why that'd happen in Axis countries in the latter years of WWII, but not in commercial guns made later.

Oh I've also seen Browning Hi-Power guns with red parts. Sometimes, it takes getting the gun out in sunlight to see the problem. But it helps to examine a potential purchase with a strong flashlight. I carry one at gun shows.

 

[bgrafsr]

I have a very nice M&P from the early to mid-thirties (6275xx) that is not a reblue that has a plum-colored cylinder. I find it both interesting and attractive. I have a K-22 Outdoorsman that's just a bit newer (6574xx) with a cylinder without a trace of the plum color. But . . . my S-prefix transitional M&P (S 9528xx) appears plum-colored in bright sunlight.

FWIW, my Ruger No. 1S receiver made in 1984 is plum-colored, while the receiver on my No. 1V made in 2000 has nary a trace.

The photo is of my early M&P.

Interesting that the ejector rod is also plum colored.