Pm and Cm parts?

[LRR]

I understand that the cost difference between the pm9 and cm9 is partly due to the barrels and the slide stop. Yet, if you look at Kahr parts on their site, the parts have different part numbers but are the same price. Are they the same? If so, what's the point?

[Scarywoody]

Makes you wonder. I can see different part numbers to compartmentalize the purchasing of the parts across models. I looked up other CM and PM and same thing. I'm sure there is a good, logical explanation.

[dohcacr]

CM has conventional rifling. PM has polygonal rifling. Both forms of rifling have their advantages.

http://www.kahrtalk.com/attachment.php?attachmentid=14150&stc=1

[kenemoore]

I think one of the biggest cost differences is the labor spent on the parts and pieces. If you look at the two side by side, the PM model has had more secondary operations the sharp edges are broken, a little polish here and there.

[CJB]

I understand that the cost difference between the pm9 and cm9 is partly due to the barrels and the slide stop. Yet, if you look at Kahr parts on their site, the parts have different part numbers but are the same price. Are they the same? If so, what's the point?

There are a few points.

First, Kahr's website is lacking. The part number Kahr actually uses within their own company is not shown, and ordering parts is best accomplished over the phone, in my experience.
Second, the C line - CW, CM, and now CT, are examples of marketing. The differences - slide stop, barrel and front sight. The rest is cosmetic.

The barrels cost exactly the same to make, no difference of appreciable amount. Both hammer forged, both need mandrels, and materials are the same.

The slide maching is the same cost - except perhaps a few more of one or the other may be made per hour, so that does factor some.

The slide stop on the C line is one piece, and two piece on the P line. Slight added expense for the P type, but both work well and are interchangable.

So really, they're the same pistol, with only very minor differences.

Why the big price difference then? Does it reflect the "cost of manufacture"? Nope! Its all marketing, how the product is brought to the marketplace, positioned and how much Joe Consumer will actually pay. Even if the P line were less expensive to make, they'd sell it for more, because folks are willing to pay more for it.

[Bills1873]

I have a cm & a pm. Pm was $412 slightly used. If I had to replace it, I would with a cm. I'd not pay extra for a pm.

[LRR]

I've read that the pm slide stop is milled and the cm slide stop is injection molded. That would be a big difference in price yet same on website.

[Alfonse]

I've read that the pm slide stop is milled and the cm slide stop is injection molded. That would be a big difference in price yet same on website.

I believe only the pin is different. Both of the levers are MIM. The pin would be turned, to be sort of particular about detail. I have never heard about a slide stop failing on a CM.

[CJB]

I believe only the pin is different. Both of the levers are MIM. The pin would be turned, to be sort of particular about detail. I have never heard about a slide stop failing on a CM.

+1

If you look at the lever from a TP/P/PM with an eyeloup, say 7x to 10x, its pretty clear that the part was molded. The pin part is some sort of godzilla steel that cannot be machined (aka "Krell Metal"). It has to be ground (or so they say). I do know its a pretty tough piece of metal. That pin fits into a hole in the lever. The pin also has a groove in its end. A tiny cross pin fits through the lever, into a blind hole, and captures the pin by that groove. The pin may, or may not spin in the lever. The pin itself is nickel plated, to permit corrosion resistance and match the finish (sort of) of the stainless slide stop lever it fits into. If you alter your slide stop, for instance rounding it, then refinish it, you'll displace the nickel plating, and the pin itself will become dark as it oxidizes. I've not had any (of four I own) become full of "red rust", just a dark surface finish, even after going swimming in the Sea at Daytona Beach.

The C series is just entirely molded, as also are most of the slide stops for any pistol out there - such as the .45 Autos from Colt's (and copies), etc.

The forming of parts by either investment casting, or metal injection molding is not a bad thing, if the process is well controlled. When Ruger pioneered IC parts, they were lambasted, and mocked. Time has proven that the IC parts are solid. Now MIM gets the bad rap, when really, Colt has been using MIM parts since at least the 1990's (maybe 1980's) for things like safeties, slide stops, magazine catches and the like.

IC is great for making intricate large castings that require only finish machining to become a workable part. Ruger has taken that to an art form, and Ruger "ghost casts" (like ghost writing) for the entire firearms trade, as well as for anyone who wants/needs high quality cast parts. Ruger's casting division is the largest precision caster in North America.

MIM (which Ruger also does) is better for small parts where detail is important and only minor rework or final machining will be needed. Think - side stops (or levers), thumb safeties for .45 Autos, that sort of thing. You can get a nice texture or checker on the surface, machine a hole or fit a mating surface during assembly, give it a blasted finish and call it done. MIM is small size, high detail, high precision. IC is large size, low detail, low precision. Each has its place. S&W uses MIM for all its hammers and triggers, and look at the level of detail they get on the checkering or grooves. Good stuff.

BUT THEY FAIL, DON'T THEY????!!!!???? No they don't, if the process is controlled. If you get slag, inclusions, voids, bad fill, you name the problem, then the recipe has gone off, and you're going to get bad parts.

Well hell's bells.... if your CNC tooling takes a walk in the woods - same thing. If your heat treatment goes south, same thing. If your forging dies are worn or misshapen.... same thing. Nobody complains about that though. Only MIM because its the newest, and the latest to have a few issues as the molding houses learn to make firearms parts. All industry has learning curves. Jeeze. And MIM is sometimes the only way to make a part. Take a real, real good look at the Kahr slide stop lever. I mean under 7x magnification. Would you want to run a CNC program to make that? Nope. Far, far.... FAR... to costly. MIM makes parts affordable.

And that's my story and I'm stickin' to it!

[LRR]

Sooooo.....I'm gathering there is no difference in the parts on the website and little difference between the PM and CM. The cost difference is 10% real and 90% hipe.

[CJB]

The parts are different in their construction.

The parts should be different on the website, but that place is lacking.

The parts are not to terribly different in practical application or implementation thereof.

Either slide stop will work, more than likely never fail, and each is subject to occasional bad parts or poor fitment.

The barrels.... toss up on which is "more expensive" to make. The hammer forging process beats the snot out of a short fat piece of steel and makes it a long thin piece of steel, with a nice smooth inner surface. The mandrel is what they put in side a precision drilled hole in the steel. The mandrel has a pattern on its outside which will become the imprint of the rifling on the inside of the steel. The only difference in cost is the price of the mandrel, which is good for many many barrels. I suppose... a conventional mandrel is a little cheaper to make, but... you gotta spread that cost over maybe a few thousand barrels, so the cost-per-barrel of depreciation of the tooling is really sorta small.

Three, or possibly four ways to rifle a barrel. One is cut rifling with a single or gang broach. This leaves a sharp edge to the lands, and you can do tricks with the depth and rate of twist as the broach goes down the barrel blank. For instance, Pope barrels were gain twist and a little tighter at the muzzle and well admired for their accuracy. Next comes button rifling, where a carbide "button" with the imprint of the rifling is pushed down the barrel hydraulically under a bunch of pressure. It irons the pattern into the metal. It also sets up huge stresses. Folks "claim" button rifling is really good, but no bench rest shooter would own one. Too many stresses. They do look pretty though. BTW, cut rifling is still the way to go for accuracy, and looks terrible! Hammer forging like described above uses a hammer machine (with hundreds of hydraulically actuated hammers) and smashes the barrel into shape around the mandrel. The hammering stress relieves the metal, and hammer forged barrels don't look as pretty as button rifled ones, but, sure do shoot well. Button rifling and hammer forging are both processes that allow inexpensive mass production. Cut rifling is very expensive because its slow. Next, is EDM rifling, which is seen from time to time. EDM is also slow, but depending on the process control, you can get tricky patterns and such. I can think of a way to EDM rifling, but... I'm not sure exactly how they actually do it. I do know that EDM is a slow process of erosion of the metal, and for high precision with little splatter, you need to keep the amperage of the EDM machine low and well controlled or you get a sort of splatter and rough finish.

Again, even if the P series were less expensive to produce, they would sell it for more, because people think its a better product. Why? Because Kahr says it is. Is it really? Well I like the dovetail front sight, but is it worth THAT much more? I guess a enough folks think so.

[b4uqzme]

Sooooo.....I'm gathering there is no difference in the parts on the website and little difference between the PM and CM. The cost difference is 10% real and 90% hipe.

For the most part. Yep.

[dustnchips]

I bought a used PM9 because it had night sights and it was only $450. My 380 is a new CW and it cost me another $80 for night sights and $40 for installation by a gunsmith. That made the cost of the 380 a bit more than the 9. I doubt that I would buy a new P over a new C though.