Sunday, February 27, 2011

Evidence of MIM

Look at some of the closeups of this entry level Remington1911.

I may be wrong but the pebbly looking areas on the parts and frame might be evidence of MIM parts.  On the thumb safety you can even see where a burr was ground off (the straight scratches) but other sections of the safety look they were 'cast'.  I'd think the rough sandy look to the metal's surface would be from the finish if there wasn't this evidence of machining too.

The frame itself looks pebbly, too.  If given the chance I'd prefer a forged slide and frame.  But how can you even tell on some guns with a lot of machining to smooth them out and a thick duracoat what have you hiding the evidence?  Is my parkerized Springfield MIM framed?  Dunno.  I kinda doubt the Colt is, but I don't know for sure.

The pistol is priced at entry-level... uh... levels, and you gotta expect a good bit of cheaper to manufacture Metal Injection Molding components and less finish work to the surfaces.  


Alex said...

What does MIM stand for?

JB Miller said...

I think it stands for Metal Injection Molding.

Richard said...

Probably all the small parts are MIM. The only one that would give me real concern is the slide stop, because it's put under real load. It's not uncommon for hammers, thumb safeties, etc. to be MIM on even decent guns (e.g., Dan Wesson used to do this).

I believe all Springfield frames are forged (by Imbel in Brazil). Bad finish is usually attributable to… bad finish. It takes time and money to get a presentation-grade finish, suitable for nice blueing. That's one reason why lower-end guns often come with a thick, ugly coating!

Last I checked, all Colt frames are forged.

Cast frames (not the same as MIM!), however, are nothing to worry about. Caspian has stated that they've had more customer problems with forged than cast frames, and they guarantee their cast frames for live against cracking. And you don't see many complaints about RIA cast frames, at least at their price point.

Tam said...

"Is my parkerized Springfield MIM framed? Dunno. I kinda doubt the Colt is, but I don't know for sure."

Your Springfield frame was forged at Imbel in Brazil. If it has an "NM" serial number prefix, it came into the US as an 80% frame and was finish-machined and assembled at Springfield's Geneseo facility, otherwise it was built in Brazil. Your Colt frame came from Bourdon Forge in CT, and turned into a gun in an industrial park in Hartford.

Tam said...

Frames are never made with the MIM process, but are cast.

Metal injection molding is not appropriate for large or thick parts.

Vinosaur said...

Interesting article. I work with a guy that has a part time gig with Gander Mountain, and he said they have had 5 Rem 1911's come back in for varying failure issues. They pulled the rest off the shelves locally and are awaiting resolution on the issues seen.

Jay said...

The story I keep hearing about Remington is that they are cutting corners in their production processes, and that quality is suffering. The use of stamped and MIM parts is part of it.

Their staple shotgun product, the 870, is apparently now made in stages at 3 different facilities. Thus there is no continuity in the manufacture of any individual gun.

Now that they have closed the Marlin plant and will be closing the Bushmaster plant, a decline in the quality of those models might be on the way.