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Old March 4, 2010, 09:41 PM   #1
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Question on appearance of phosphate finish

I have an M1 rifle, A Springfield originally made in '44, that is from the CMP. The barrel is an SA '46, and sometime or other, the receiver was re-parkerized.

When I originally got it, the receiver was quite light in color. That was in '08

Now the receiver has taken on a pleasing olive green color

My question is:

Why has the color changed? All I've ever done to the metal is clean it (well I do fire the rifle, too). I run a silicon cloth over the metal once a month or so. I removed the receiver to oil the stock in every case that I worked on it. I am not complaining about the color, it just struck me today that it is darker than I recall it when I first got it. I did not expect the park to darken up at all, I had accepted the fact that the receiver would just be a light gray and maybe I'd have it re-done at Tim Shufflin's place one day or maybe not
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Old March 5, 2010, 12:32 AM   #2
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The WWII rifles were greenish from day one, but a gray finish can turn a kind of brown-green over time from oil, perspiration, etc. If the finish was there originally, the receiver should show the green tinge inside and in places like under the rear sight where nothing touches it.

FWIW, WWII M1's were not a light gray; that is almost always a post-war refinish. They were a smooth gray with a greenish tinge. Korean era rifles had darker gray Parkerizing without the green undertone.

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Old March 5, 2010, 06:39 PM   #3
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Thanks Jim

Understood re: the original colors, etc. It's a CMP rifle, re-barreled at an arsenal after WWII. No original finish is left on the receiver. I guess I'm not explaining well.

Here's a lousy photo of the receiver heel; I'm usually not a bad photographer but today ain't my day. When I got it in '08, the color would have been a light to medium gray. Here it is now. I would say that this almost approximates the color I see when I hold it my hands under natural light, but monitor differences can affect the color depending on which monitor you have and what your settings are:

This one's better but the flash lightens the color up a bit; the stock is not this red under natural light

I don't attribute this uniform color to sweat stains. I understand that oil is trapped by a phosphate finish and makes it darker. This is undoubtedly darker...but I could never, ever detect any green in the park until recently

I'm not complaining about the color; I'm pleased actually.

Last edited by Chris_B; March 5, 2010 at 06:44 PM.
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Old March 6, 2010, 11:42 AM   #4
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the original wwll parking was about the color of your mag release(manganese parking). the green tint came from cosmoline(or any petroleum based lube). the arsenal that had the gray parking(Zinc phosphate). On a freshly done manganese you can dip it in a dark machine oil or used motor oil and get the green tint right away. Haven't tried it with the zinc yet.
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Old March 6, 2010, 01:59 PM   #5
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Hmm. So I'm probably doing this unknowingly, as I clean and/or use the rifle, getting oil and grease on it, then cleaning etc. Interesting. I thought I was stuck with the color I had. That's a nice surprise
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Old March 6, 2010, 04:01 PM   #6
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This topic comes up periodically. Most of the Garands I see are zinc Parkerized. I do my own with manganese solution because it is darker, more dense, thicker and tougher, and the Parker company formulation is available from Brownells, which I use. You still see some earlier zinc Parkerized '03's that are fairly gray compared to the green Parkerized Garands and '03-A3's of WWII.

The oil and grease will, indeed, cause some color change over time, but I have a pet hypothesis (have not set up to prove this) that the difference in the WWII guns may be that the process by then had evolved so Parkerizing was followed by a dip in very dilute, hot chromic acid. This was to passivate and get chromium oxide on any free iron in the Parkerizing layer itself, to prevent rust speckling. But any free zinc would also react with the acid to form zinc chromate, which is greenish yellow. Darkening by subsequent immersion in the sealing oil, could then finalize the color. The tech manuals I've copied on the topic admit the military did dye Parkerizing in some instances, but no details are forthcoming as to when or with what? So it could also be that? Someone in Canada was offering a green phosphating service a few years back. Don't know if they're still at it or not?
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