I saw a model 28 on one of the for sale boards. The barrel was described as "plum" in color. I have a model 28 with a cylinder that's very much the same way. My gunsmith said it was stored in the sun and different metals will react differently to direct sunlight over the years. Does anyone else have experience or knowledge in this area?

Normally it is a sign of a reblue. The issue (as I understand it) is that the chemistry of the bluing materials got out of whack and so the different parts responded differently. On my S&W's I have only seen this on re-blues and it seems reasonably common.

I do have an H&K P7PSP I bought factory new and the slide has slowly gone purple so it can be just due to the different metals and different bluing. I know my P7 started out the same shade as I bought NIB and it has never been anywhere else.

__________________
SWCA 1646

It's caused by a number of reasons. As Peter says, one of them may be the bluing salt mix is off or contaminated. Most commonly it is because the temperature of the salt bath is wrong. Some alloys simply turn plumb colored when you try to blue them, the cast steel of the 1964 Model 94 Winchester receiver is the most notable.

Its not from the sun but certain light makes it more apparent,
This 29-3 has a purplish barrel and cylinder but the frame is fine.


same gun outside

I blued many firearms over the years. The temp has a lot to do with parts turning plum colored . repolishing and lowering the tempeture corected many of the plum problems but not all. I was told back in the 50's by the then Remington field rep that the carbon content had a part in the problem.


Good Grief, my memory must be failing, AALK8944 you are right it is nickle not carbon that is the problem.

Paulj

The "Plum" color is a result of aging of the bluing and the Nickel content of the alloy used for both the barrels and cylinders. If anyone ever paid attention they would notice that it is always the barrel and cylinder that show this tendency, and never the frame, sideplate or yoke! Just that should be adequate evidence that incorrect temperature, contamination of the salts, or other external cause is at work! If any of these were a factor you would see purple frames at times too.

__________________
Gunsmithing since 1961

I've bought a couple of S&W revolvers that had the plum color on them and one was the cylinder and the other was the side plate and it's a result of problematic bluing or so I've been told. They were both guns I was going to shoot a lot so I asked for a discount and got it and I bought them and never looked back.

I appreciate everyone's response. Interesting observations. This particular model 28 shows little, if any wear, and locks up very tight. The difference in color still bugs me. Perhaps a trip to "Ford's".

Yep, the correct answer as to why a blued firearm turns a plum color is that there is no one correct answer!

Bruce

In the shotgun section of the Marlin Collectors forum there is an extensive discussion on this subject. Marlin 90 shotgun recievers were made with " malleable " iron and if blued will turn plum after several years. 90s are excellent shotguns and it is almost impossible to wear out a reciever, its just that they turn plum with age. Marlin phosphate coated most of the recievers, but there are some plum ones out there. So, I would agree the plum color has to do with the alloy used

My very early first year of production M581 four inch has a deep plum color barrel. The frame and cylinder are normal blue.
I also have a mid 1960's Ruger Single-Six convertible with a plum colored frame. Both revolvers are 100% original finish.

__________________
Virtue,Liberty & Independence

It use to be, that you had to know the Alloy mixture to have the right salts to blue it correctly. Or at least we use to have some salts like that for our blue tanks. If it comes out Plum its temperature if it turns plum over time its usually Alloy Content.

__________________
Smith,Wesson,and Me-DirtyHarry