Greetings from Wisconsin!
Greetings from Wisconsin!
Howdy All, I just bought my first 870, on Gunbroker, and its not even here yet! Will be remodeling it into the home defense role. I just spent the better part of 2 hours reading a lot of very informative posts here! OK, so I have a stupid question, or at least I haven't seen the obvious answer myself! When we talk about 870 extractors I see them described as either the good forged variety, or the bad MIM type. What does MIM stand for? Made In Mexico?
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Synchronizor
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Re: Greetings from Wisconsin!
MIM stands for Metal Injection Molding, an advanced powder metallurgy manufacturing process that improves upon older powder metallurgy forming, allowing for large-scale production of finely detailed parts with strengths, tolerances, and densities nearly identical to machined parts, but with far less wasted material and expense.
There's nothing bad about the MIM extractors. Once in a while, you'll hear stories of defective ones causing problems (mostly because MIM tolerances aren't quite as good as can be achieved with other methods), but those aren't very common. The 2-4% decrease in strength or density with the MIM material really isn't an issue, since the 870's extractor is designed to be pretty beefy - almost overbuilt - and the dimensions of the MIM and non-MIM extractors are identical. My 870, my friend's 870s, and many 870s owned by members of this forum have MIM extractors that work flawlessly. Some people upgrade to the higher-end forged extractors just because they like the idea of having it, and having a weapon you're fully confident in is certainly worth a $15 part; but don't believe any hype that the non-MIM extractors are inherently unreliable or failure-prone, because they're not.
There's nothing bad about the MIM extractors. Once in a while, you'll hear stories of defective ones causing problems (mostly because MIM tolerances aren't quite as good as can be achieved with other methods), but those aren't very common. The 2-4% decrease in strength or density with the MIM material really isn't an issue, since the 870's extractor is designed to be pretty beefy - almost overbuilt - and the dimensions of the MIM and non-MIM extractors are identical. My 870, my friend's 870s, and many 870s owned by members of this forum have MIM extractors that work flawlessly. Some people upgrade to the higher-end forged extractors just because they like the idea of having it, and having a weapon you're fully confident in is certainly worth a $15 part; but don't believe any hype that the non-MIM extractors are inherently unreliable or failure-prone, because they're not.
Re: Greetings from Wisconsin!
Thanks for the rapid education, Sync! I guess that MIM is pretty much the same as what we older guys simply referred to as "powdered metal" technology. And I believe that all got started back during WWII. Like you say, casting more intricate small shapes, and bypassing machining operations to increase production and decrease labor. By the way I didn't mean anything derogatory with my guesswork on the meaning, and I do apologize if I have offended anyone!
Greetings from Wisconsin!
We'd love to see photos when it arrives. Welcome to the forum!
Last edited by JBall on Thu Jul 25, 2013 3:48 pm, edited 1 time in total.
Re: Greetings from Wisconsin!
Thank you! And I will post pictures!