Plum color

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Nov 17, 2009
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Webster, MD.
I was wondering what causes the plum coloring on some parts. While looking over my Bearcats the other day I noticed that the loading gate of my 1996 model has become plum colored. Perhaps it has always been that way but I never noticed it till yesterday.
 
Some alloys of steel will do that when the old style bluing salts were used.It often takes years for the color to change.
Here is a picture of an old WW Greener shotgun I have. It was reblued by Navy Arms in the 60`s. Look at its color now.
 
I have seen the plum color on a recent shotgun reblue. The person who did it said it was not in the tank long enough and the blue was too thin. He reblued it by putting it back in the tank and it came out fine. So thin original blueing is one possible cause.
 
From another member:

rugerguy
Ruger Guru


Joined: 11 Dec 2002
Posts: 13246
Location: Ohio , U.S.A. Posted: Wed Feb 27, 2008 9:49 am Post subject:


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It is pretty well explained in Larry "the x-con" Wilsons book "Ruger, the Man and His Guns.............."
bottom line it's , in the case of the Ruger, a "casting issue", the "mix ( or they call it the batch) is made of a bunch of different metals to attain the "proper" engineered alloy of 4140 Chrome-moly steel that is common for use in making firearms...Ruger has been doing this on their own for many years, and have it down "pretty" good for the MOST part. BUT once in a while the batch may be not thoroughly mixed or when pouring the mix into the mold, the use of silicon was/is used to aid in the "mixing /flow of the material into all the creases and crevices...anything out of "spec" ( too much , too little...) will affect the outcome of the metallurgy and its properties...now come time to "blue" the parts and if there are " hot or cold spots, streaks, etc, the blue will come out a different color in these areas... just as heat treat ,(hardness) can affect the bluing, so does the actual metal itself....now, Ruger collectors tend to find this "color" hues variations "nice, cute ,pretty, different" what ever, BUT it is still a "boo boo", a flaw, wrong.... these same colors can also be gotten by improper temperatures of the salt bath ( bluing solution) and also by not leaving the parts in "long enough" and when this occurs with ANY other gun company ( for the MOST part) they reject it or reblue it.... this is also quite common when 'outside' sources reblue any firearm and they are NOT "good at what they do", this is often a sign of a "reblue", so it is a "catch 22"....no WBR never threw anything out nor "wasted it", that's why years ago , in the beginning they even offered to "redo" any firearm "free" for the owner, a letter was put in the shipping carton ( box) along with the firearm ( maybe Flatgate will post that "neat" picture of the original 'letter from Ruger.......)
Problem is MOST firearms ' "experts" ala Winchester, Colt, S&W and others, do NOT like to see this "plum" and will pass up on buying any of the guns that have this as I said, it is "wrong" ....not desirable to any of those makes and models....ONLY the Ruger collectors get off on this...and yes, it is "nice, cute, different" as all humans are....yes, I even take a liking to it myself....BUT having been in the refinishing business since the late 60's, we KNOW it's "wrong" and would NEVER put out a job that has this....by the way, if it is in fact , in the metal makeup, and you do a proper "reblue" job, it will usually again "turn plum" or "streak".........
yes, you can at times address this by upping the temperature range but this is NOT good for your 'salt bath" we used to save doing the nickel steel guns and such towards the end of the "bath life" as they will ruin ( kill the bath) so the old 'nickel steel ' Winchesters went in "last" and yes, they would come out and stay "blue" for the most part, as will any of the Ruger metal parts...........................
This is a simple ,easy explanation, nothing "technical", as I am NOT a metallurgist, nor do I even LIKE to use/play/work with ANY "salt bath" makes MY skin crawl, and get itchy all over.......I do the prep and final fit , all the "hard" stuff, and leave the "cooking" to the 'chef'.........


and to answer your question, YES, even today , once in a while you will see parts at times that have this "color" makes no matter the model either.
 
Many firearms take on that plum color, not just Rugers. I have a Finnish Valmet 12 ga. O/U made in the 1960s that has a plum receiver now. It was blue when my wife gave it to me in 1986. Many happy memories in that gun, and I LIKE plum guns! A friend has a Winchester .22 pump model 61 with the same color receiver, made in the late 1940s.

Chuck, I envy you that Greener GP shotgun! You'd be surprised how many of those are still doing what they do in odd corners of the world! They don't break.
 
I have a p95 here that I bought my son for Christmas a few years ago when he still lived at home (his wife wont let him have it that's why its in my possession lol) but anyhow pretty much the whole slide turned plum/purple. the gun is roughly 4 or 5 yrs old. kinda a shame actually now that I think about it I positive there hasn't been 200 rounds through it maybe 150-180 and I know 40 of them were from me lol
 
Another make that frequently turns plum as time wears on is the Heckler & Koch P7 series 9mm autoloaders and these were certainly anything but inexpensive.
 
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