Metal Injection Molded parts

[Globallyoff]

I have a question especially for the engineers on here with some experience with MIM technology. Is the MIM process inferior to casting parts or has the quality control of some of the pistol manufacturers slipped?

I recently bought a Gen 3 Glock 19 and had the problem of ejected casings hitting me on the chest and face/head. I've never had this problem with my Gen 2 Glocks. The extractors in the newer Gen 3 Glocks are MIM, and there are multiple threads on GlockTalk about this problem. I did remove my extractor and smooth out the molding marks on my extractor. It was much smoother in the slide after that. I plan to test fire it this weekend. And I dont "limp wrist" the pistol. It does cycle 100% thru about 300 rounds so far.

I've heard similar things about Kimber 1911 pistols, but both of mine are old school, and don't have any MIM parts.

 

[charliepapa]

the general consensus (here, there, everywhere) based on my reading is that MIM parts = suck. it's done as a way to reduce the cost of production, not because it's better. once I understood that the process was similar to how pills (medicine) are made, I understood the lack of faith...

 

[Sin-ster]

As I've been told...

There's a lot to consider in terms of the scope of this question. Some parts (with less physical stress) are not a liability if MIM'd. And not all MIM processes or quality are the same-- which goes without saying. Honestly, in certain cases, the cost savings far outweigh any perceived shortcomings-- as is the case with the extractor-in-question.

A Gen 3 G19 with extraction "problems" is not a matter of a slipping manufacturer. (Even on a Gen 4; it's a matter of slipping engineering and marketing. But I digress...)

Now that it's been mentioned, I remember a few cases smacking me in the forehead out of my G17 when I first picked it up. Unfortunately, it was so long ago and so many things have changed since then, it's hard to pinpoint exactly why. I didn't "limp wrist" either, but I'm unquestionably a much better shooter now than I was back then. I also swapped out the recoil spring for a lighter one, which may have played a factor. Most importantly, I've shot the living crap out of the thing (30kish? I lost count)-- so any kind of bur or obstruction has probably worn away by now.

It should be a pretty simple problem to troubleshoot, as the Glock is so easy to work on. (Youtube can teach you how in a matter of minutes.) If you have access to other guns, you can simply swap out the pertinent parts and work through the process of elimination. Or just buy a new one-- they aren't super expensive, and it never hurts to have a spare. (Yes, the extractor will eventually go out-- but most people will never shoot it enough.) Letting other folks shoot it will rule out the possibility that it's just you.

Did you buy the gun new or used? At any rate, it might be worth checking the plunger spring-- I've seen them rust out before. Come to think of it... Mine did, and I replaced it and definitely haven't had a brass kiss in the face since then. (Just not sure if I was still getting them BEFORE.)

 

[goteron]

MIM parts are fine. I doubt HK, Glock, and others would not see the false savings. The cost of returns would VASTLY outweigh any savings.

The MIM process has evolved a lot since it started and they understand it much more now.

Just like with everything, if they were made by a quality company, they are fine. The problem is you get small companies farming out these parts to crummy MIM providers and putting a bad stigma to them.

 

[charliepapa]

oh well, sorry for my apparent misinformation. it must have been some other idiot I was listening to about the mim parts. I could have sworn I read a thread here about S&W going on the cheap with mim parts that were failing in the firearms. thankfully someone in the know chimed in.

 

[Vanilla Gorilla]

The Aerospace uses MIM parts in all kind of critical roles. The problem isn't the MIM its bad QC and QA protocols when its used in the firearms industry that cause the problems. Glock in particular uses the same protocol for ND Testing of MIM components that Airbus uses. I doubt there is a single part in a Glock that can be MIM'd that isn't.

 

[Mjolnir]

Just had a detailed conversation with GKN and though I work with an auto exhaust supplier my interest is in aerospace, motorsport and firearms applications. A large percentage of aerospace applications will have multiple alloy, variable density MIM but usually sinter forgings. People all over the net speak of "MIM connecting rods" hub those rods are sinter forged; two very different processes.

That said, if the part is initially designed with the limitations of MIM taken I to consideration I've no pro LEM with it. Nowadays, its driven purely by piece part cost reduction, I think they call it. There are grain structure differences that if given the option I'd prefer a part machined from a forged ingot. Sinter forged parts are a viable alternative as they are carburized to give them a deeper hard outer layer and if designed properly it will be just fine.

It's all about reducing "investment" cost in the firearm industry.

 

[Globallyoff]

The Glock 19 was purchased new by the way. I went out to the range today, and I have to say that removing the casting marks from the extractor made the gun eject much better. It still doesn't like Remington UMC 115 gr. 9mm, but I only had 2 rounds eject back at me out of a box. Monarch 115 gr. ammo (Serbian) from Academy did better as did Federal law enforcement hollowpoint 124 gr. All cases went over my shoulder off the the right or far right. The gun has never jammed up, but now it's much better to shoot at the range.

 

[Mjolnir]

You can try a Lone Wolf Distributors extractor. It may help though it will depend on the root cause of your issue. Their part is cast versus the OEM version which has horrid fit and finish.

It looks like the polish helped but keep in mind it has a very thin hard surface; any polishing will remove this and you may experience accelerated wear.