LMT BCG and MIM gas keys.

[durus5995]

I remember when LMT switched to MIM gas keys back in 2009 there was a big ole crap storm. Now that some of these MIM gas keys have been out for a couple years I was wondering are MIM gas keys as bad as everyone thought way back in 2009? Have there been any substantial report of major failures?

[ALCOAR]

There has not been a single reported failure of one of these MIM keys to date....let alone a picture to verify the claim.

Keep in mind LMT is driven by what the Military Contracts they hold demand....one of which is the MIM keys, LMT tested these MIM keys to 25,000 rds. w/o a single failure.

I just got a brand new LMT F/A bcg w/ a new CQB MRP upper and it did not have MIM keys....this is most likely because LMT gives the whiny civilians the non MIM keyed BCGs while the MIM ones go to fill the Military Contract.

[Blankwaffe]

Ive not seen a failure reported either.
The MIM gas keys actually started showing up in the summer of 2008.Ive been running one since the fall of 2008 and have yet to see an issue with the MIM gas key.
So I say its a non issue that has been absolutely beat to death with speculation.

[Triton28]

No issues here.

This has been a huge boogeyman. There is no reason to believe properly executed MIM is a problem in small parts in firearms. Combine that with LMT's excellent reputation and I don't think anyone should be worried.

[thisaway]

Please help educate a newbie: how can you tell if the key is MIM?

[bkb0000]

Please help educate a newbie: how can you tell if the key is MIM?

it'll have a circular mold mark between the screws on top. and your staking will be cracked, rather than just deformed.

i haven't kept great track of this stuff.. but i know i've got about 8,000 rounds on one, and have put thousands of rounds on others that have come and gone from my possession. i was a little irritated back when they started doing it, but now i don't give a flying mc**** with cheese. it's a total non-issue.

[durus5995]

Please help educate a newbie: how can you tell if the key is MIM?

Basically instead of machining the gas key it is a molded part in a die.

http://en.wikipedia.org/wiki/Metal_injection_molding

[ALCOAR]

I was going to remind the OP that if MIM parts were a problem than we should def. not be flying ever on modern airplanes:eek:...Tons of MIM parts.

I clicked that wiki link and it had a great paragraph of info summing up MIM...

" Applications

The window of economic advantage in metal injection molded parts lies in the complexity and small size of the part. The products of metal injection molding are up to 98% as dense as wrought metal and used in a broad range of applications (including medical, dental, firearms, aerospace, and automotive.) Tolerances as small as +/-.003" per linear inch can usually be held without secondary processes. The difficulty of fabrication through other means may make it inefficient or even impossible to manufacture otherwise. Increasing complexity for traditional manufacturing methods typically does not increase cost in a metal injection molding operation due to the wide range of features possible through injection molding (internal and external threads, miniaturization, branding). "

[Blankwaffe]

Here is the link to the LMT gas key study that Grant posted sometime back.HTH

http://www.gandrtactical.com/images/archive/LMT/Gas%20Key%20Study%20Response%20June%202009.pdf

[ALCOAR]

I wonder exactly how the 135,000rds. were "test fire" or broken down...diff. assembles w. the MIM keys or all together on one unit??

LMT told me firsthand that they tested a single unit to 25k...not a single failure.

LMT is unmatched in the amt. of test firing and proof testing they perform on their kit and guns. It's mind numbing the amt. of rounds my pal told me they blow through annually....I drooled instantly, only to be reminded that it sucks apparently when you do it for a living and its part of the job to go blast a cpl. K's worth of rds. though a 10.5" MRP CQB on a Guardian Lower.

[durus5995]

Thanks for the info guys. I have never had a problem with the MIM keys perosnally but I am selling an upper and I was thinking about selling my LMT carrier and the guy had a fit that it had the MIM key on it. He was baseing all the facts on all the 2009 fud that pops up when you google it. He said he would be better served with a DPMS BCG that he cousin was going to sell him. I wasnt going to argue the point lol.

[bkb0000]

If you could point me in the direction of where I can read about it, I'd be pretty grateful.

there was a lot of stuff on right here on M4C about it a couple years ago. i can't produce any links off the top of my head. i can vouch for all the test firing they do, however.. every gun or part they send out is absolutely filthy from all the individual test-firing they do.

[mark5pt56]

Look, I deleted the previous post--keep this on topic with the gas keys. No need to start arguing over other topics.

[scottryan]

Keep in mind LMT is driven by what the Military Contracts they hold



And what contracts would those be? And where to they require a MIM key?

[mark5pt56]

I think we learned enough. Shoot on with your MIM key. If you don't like it-change it.