Have 2 ruger m77 mkII from 1993 and both have distinctly plum colored receivers, the barrrels were of regular blue, was this just a bad batch of bluing salts? Neither has the original barrel and hasn't adversely affected anything to my notice, was just wondering?

They were blued on a Monday or Friday.

Nothing wrong with then, it's a steel vs chemical reaction. The bluing salts weren't strong enough or the metal wasn't left in long enough.

Older Leupolds do this too.

Adam

A cast reciever will often blue to a different color than the barrel in front of it. I used to have the same issue with high nickel steel as well. Different salts handle the cast metal differently. The concentration of the salt controls temp. So if there is too much water the temp will be a touch low and red or plum is often the result. I have had MarkXs that looked the same way.

It is only look not function

I can understand a gunshop bluing the occasional cast receiver and getting it wrong, but you would think the manufacturer would get it right. I've seen an awful lot of plum-colored Ruger receivers.

thanks for the input guys figured it was a bluing glitch not a heat treat problem. Actually the pawn shop where I bought them gave a discount for the mismatched bluing

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I can understand a gunshop bluing the occasional cast receiver and getting it wrong, but you would think the manufacturer would get it right. I've seen an awful lot of plum-colored Ruger receivers.

I bet it left the factory the right color. The bluing can turn plum over time. Like I said I've had MKx that were plum I believe the springfields were another one that turned plum due to the nickel.

I have a 257 Roberts like that; they left the factory that color; as stated it is a combination of steel hardness and bluing salt formula and temp. Old shotgun frames, being made from malleable iron, will usually turn out red unless you do some tricks, like lower the temp and I forget others. Using the wrong bluing temps (as in a fast factory operation) you can turn any alloy steel reddish.

The investment cast receivers turn plum colored with age and there is nothing to be done to change this, well, except buying a rifle with a receiver cut from billet.

The alloy steel used with investment casting has to have added silica so it will form better in the molds. This was one of the problems we tried to solve with the Omega III actions in 1973. The answer from the Labs came back saying it was the silica. The first actions were made of 4340 or 4140 bar stock. No problems. Started into the manufacturing using investment casting and the red shows up. There was a black chrome company that we used on a few of the recievers which was a plating process. Some times a quick chill on the metal between bluing will help make the metal turn darker. We tried several different brands of bluing salts with the same results. I don't know of any process which will keep the metal the same deep blue color. Red will appear on some actions more than on others of the same casting. The hardness of the actions are not changed and test on Ruger actions are some of the tuff ones to engrave. Ask any engraver!!!

I may be wrong on the name of the added material put into the casting metal as this was 30 yrs ago. I wish I had kept notes when I worked for Omega Arms, Inc.

Be happy--- 25 years down the road a collector will pay MORE for a nice plum gun!

Les, you remember correctly. When Bill Ruger started manufacturing receivers and parts with the investment casting process he had the same problem of receivers and parts turning purple with age. Nothing to do with the bluing process. He finally hired Batelle Memorial Insitute in Columbus, Ohio. In time they came back with scientific analysis stating it was the silicon added to the steel. It's purpose was to help the steel fill out the molds properly. Ruger then experimented to determine the least amount of silica to use in order to eliminate or at least limit the amount of purple after the steel aged. I have friends in the investment casting business and they have confideded to me that they prefer a certain amount of silicon in the mix for the same reason.

After rebluing many guns over the years I have observed the same problem with other investment cast guns. The old Charles Daly O&U's, Mark X Mausers, Wby Mk V's, Shilen DGA's, etc. etc. With the correct temperatures and techniques they can be reblued to a deep blue black.

As for a Ruger's action strength, I know of a Ruger No.1-B in 25-06 that a customer fired a .308 factory round in it. He brought it in complaining about the Ruger deforming his brass. Yes the bullet did exit and headspace was measured still with in factory specs.

Rust blue is the cure for purpleitis.

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Rust blue is the cure for purpleitis

Now that is a fact

The Mark X was investment cast??? Learn something new every day.

A time in the past was most people wanted a high polish mirror finish to signal all animals to watch out for this hunter. Ha Ha

I know that rust bluing will cover these actions, but I have never found a way to make a high polish finish with rust bluing.

One of the requirements in gunsmith school in 1961 was to write a research paper correctly as we had learned from Eng.101. Yes we had to have credits to transfer to a four yr school in order to get the Associates degree. My subject was RUST BLUING. I read all I could find at that time on the subject. I still don't like rust bluing!!! I was doing rust bluing before I went to gunsmith school.

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Originally posted by Lynn Beier:
Have 2 ruger m77 mkII from 1993 and both have distinctly plum colored receivers, the barrrels were of regular blue, was this just a bad batch of bluing salts? Neither has the original barrel and hasn't adversely affected anything to my notice, was just wondering?

I had a Model 54 Winchester where the action was plum color. My Mexican small ring Mauser's bolt stop spring was plum and stayed that way after being blued over, just a bit darker.

That might be high nickle content.

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Originally posted by Scrollcutter:
That might be high nickle content.

Seems reasonable. Not quite stainless steel. BTW, I've read that purple hues can be overcome by using Brownell's Oxynate #84 prior to their standard Oxy 7 hot bluing. "84" is a stainless steel blackening solution. Sounds like the process is rather invloved and not for the DIY. Here's an interesting read on firearms metal properties. http://www.rifleshootermag.com.../guide-to-gun-metal/ CB