So What is MIM Now?

[BluegrazzGuy]

Sig formerly advertised no MIM parts. Their advertising now states "quality parts." My question is what part(s) are now MIM?

In one thread, the OP states the thumb safety and possibly the grip safety are MIM. http://forum.m1911.org/showthread.php?t=51600

In another thread, one poster thought only the disconnector was MIM. http://forum.m1911.org/showthread.php?t=51266

Now, I don't want to start a debate about MIM parts themselves, but I would like to know from anyone with information about MIM parts in current production Sigs.

[Solid]

My thumb safety is MIM or something cast for sure. My grip safety doesn't seem to be though.

[XGunslinger]

Only the disconnector, from what I've heard. And that is only 2008 build. Both of mine were built in '07 and have no MIM parts.

[tenalpha10]

Both the thumb safety and grip safety on my XO appear to be cast.

[sigmax]

Still remarkable few MIM parts for the GSR's price point.

[HAIL CAESAR]

Alot more companies could but out a non MIM pistol but it would take a little out of their profits. And they aren't going to do that.

[dstrbd223]

cast and MIM are not the same thing- correct?

[XGunslinger]

MIM=metal injection molded. Different from cast, which is machined, as is forged.

[rduckwor]

Both the thumb safety and grip safety on my XO appear to be cast.


Mine as well. 2008 build.

RMD

[bountyhunter]

cast and MIM are not the same thing- correct? Both go in a mold and have mold marks.

CAST is made by pouring hot molten metal into a mold and letting it cool. Usually the density is about 60% of a forged part (much lower strength).

MIM forces a blend of metal powder and glue into the mold. Then the part is taken out and "fired" to bond the metal into a solid part. Typically 90 - 95% as dense as forged steel parts. MIM is probably better than cast in most respects. MIM can typically be made to specs which are tight enough that additional machining is not required.

[XGunslinger]

Both go in a mold and have mold marks.

CAST is made by pouring hot molten metal into a mold and letting it cool. Usually the density is about 60% of a forged part (much lower strength).

MIM forces a blend of metal powder and glue into the mold. Then the part is taken out and "fired" to bond the metal into a solid part. Typically 90 - 95% as dense as forged steel parts. MIM is probably better than cast in most respects. MIM can typically be made to specs which are tight enough that additional machining is not required.

One plus to cast, per pistol makers, is that you can harden it to a much higher Rockwell than a forged piece. That's the reason FN went to a cast vice forged slide in the Hi-Power.

[BluegrazzGuy]

CAST is made by pouring hot molten metal into a mold and letting it cool. Usually the density is about 60% of a forged part (much lower strength).

I have never heard cast being only 60 percent as dense as forged steel and can find no reference to this. Can you please post your sources?

Depending upon the casting involved, it can be quite good. Caspian frames, for example, are cast. MIM can also be pretty good but not as good as forged or good casting. Depending upon the part, good MIM parts may be okay but not for other parts.