[cslinger]

Every once in a while I come across a P7 with a pretty hideous beet or plum colored slide. Why is this?

I have a really nice SIG 225 that has the same effect on the hammer but that is kind of cool. But the whole slide would be different.

So what is the deal with the plum colored P7s. Were they made to match somebody's shoes?:)

Thanks
Chris

[Jim Watson]

It is usually said that some particular alloys or heat treatments take a plum color from the bluing solution. But that doesn't explain why some guns are plum and others of the same make are blue. Or why you can have a purple gun redone and it come out blue-black like one of mine.

Brownell's instructions for their bluing salts say that a reddish coloration is due to letting the tank temperature get above 292 deg F. (And that a gray cast is from a temperature below 285.) Hot blues are done with the solution at a boil; the dissolved salts raise the boiling point far above the 212 of pure water. As water boils off, the boiling point goes up until the operator adds water and it comes down. You can't do much with the burner, a liquid is boiling or it isn't; turning the heat up just makes it boil faster, not hotter; turning it down will let it stop boiling which is to be avoided with bluing. A seven degree range to control by composition isn't much.

I suspect that the metal can affect the sensitivity of color to tank temperature, that whatever steel H&K uses for P7 (and whatever Ruger was casting up for early Blackhawks) requires that the temperature be held closer than other alloys. But it is apparently still a matter of temperature control. All the other problems they describe with a bluing setup lead to uneven color, and that gun of mine was perfectly uniform, all over. Wish I had left it alone, it WAS distinctive.

[cslinger]

Thanks for the detailed answer.

I assume this only affects the coloring of the steel and has no ill affects on it's strength or longevity.

Thanks
Chris

[Handy]

It should also be noted that once black P7 slides age into plum. Again, it could be a minor QC thing, or a direct result of the alloy's properties.

[cratz2]

I see this everyone in a while on various other guns. Saw three Kimbers in a shop in Kentucky and all three of the slides were slightly plumbish. They guy in the stop, who otherwise seemed pretty knowledgable, told me that this was the result of bluing a hardened stainless steel slide.

[Jim Watson]

If he thinks you can blue stainless steel, he isn't very knowledgeable.

There are some processes that will blacken stainless. The few guns run through that mix that I have seen were flat black. Not to say they can't turn plum, just that I haven't seen even one.

[cratz2]

I've been told by three or four gunshops that many of Kimbers (Royals and higher end 'blued' guns) are made of stainless steel. I know traditional bluing isn't supposed to work on stainless and I know that many gun shops have uninformed folks working there... maybe this is just one of those widely dispersed myths?

[sanchezero]

And CS,

It has no effect on the pistols performance or longevity. All it does is support the NP3 and hardchroming industries.

:)

[CWL]

Plum colored P7 slides is really common (2 of my 3 were shaded plum), just something to do with how HK does these slides -and as has been pointed out, it probably is because of the steel used. Sometimes the color will fade from a dark color to plum over time. Worst case is when both sides are different colored.

It has also been claimed that refurbished P7M8s do this more because they have been reblued as part of their refurbishment.

Bluing on a gun doesn't have to be blue, it can range from black to blue to purple to brown.

[ether]

Anyone ever notice how the old style Sig hammers (the forged ones....not the newer cast ones) tend to get purple over time? I think the grade of steel receiving the finish has much to do with the final color. I've come to equate a purple hugh with a really good grade of steel. I may be completely off base, but to me it's more a sign of excellence than a cosmetic flaw :)

The 1996 P7M8 I just got (commercial, not a refurb) has a very "plum" slide, and I actually like it.

[MoNsTeR]

I've heard that a high nickel content leads to the plum coloration.

[six 4 sure]

Always wondered why the slide on mine was colored different. Now I know why, guess I'm going to have to check the hammer on my P225 now too.

Six

[modifiedbrowning]

My 225 has the "plumb hammer", I never really noticed it until I just checked it.



edited to fix my spelling.

[Handy]

My 225 hammer isn't quite plum, more brownish.

The factory replacement P7M8 slide I have is very plum. So was the PSP I had. They came that way. Others age into it.


You have to wonder if ALL P7 slides are actually plum, but they do something to further blacken them, like a dye or something. Just a thought.

[Tamara]

First refurb P7 I had definitely had a plum-colored slide (obviously refinished after the crest had been milled off). Most recent refurb has a more blackened slide, but it had had the mill-mark removed and the slide refinished before I bought it.

I, too had heard that it relates both to the finishing process used and the nickel content of the steel.