Saw on another site that someone had confirmed LMT was changing their carrier key manufacture to MIM. There was a shit storm about this.
I was wondering if anyone here knows if this is a fact.
Regardless of whether it is a fact, would it matter? I don’t know anything about MIM other than people say it is bad but can’t really explain why in small words for a small minded person.
If this is an issue how would you tell if the key is MIM?
What is mil spec since I assume it is not MIM?
I am not flaming LMT just wondering if this is an errornet issue or something to look out for.
I hate to post a cut and paste from another forum but I can’t find very much searching on google for “MIM vs Cast” and “MIM vs forged” and “MIM vs Billet”
This is from a knife forum and I have no idea if it’s valid:
"Yes and no on the casting. MIM is a derivative of casting, but the metal is mixed with a polymer binder and cast into a larger than finished part size mold (usually 15-20% larger from what I understand). Then it goes into a furnace to extract and burn away the polymer, so your end result is closer to a sintered metal part than a cast part.
If the search function were more accomodating, you would be able to find other discussions on this topic. This has been discussed previously. Unfortunately, it’s near impossible to find those discussions.
samcolt’s cutnpaste is accurate- that’s MIM in a nutshell.
i’m not sure what exactly the spec is for gas keys, but it’s steel and chrome-lined, not MIM
MIM keys can be identified by their brittleness, which is seen in the form of cracks at the tops of stakes, and i think i rememeber reading that you can see the injection sites as little circles somewhere on the top of the part.
The key doesn’t really take that much abuse… all it does is relay gas from the gas tube to the carrier. surely it’s under quite a bit of gas pressure for very short durations, but the part isn’t banging around against other metal parts… just the gas tube a bit.
i have to admit that my opinion is a bit biased by the fact the LMT uses or used MIM parts- makes me think things like “well it cant be that bad, if LMT is doing it.” for the record, i currently possess about 4 LMT BCGs, none of which have MIM keys, and each have been purchases at different times throughout the year. likewise, in the last couple of years, i’ve probably purchased well over twice that many, and haven’t ever NOTICED any having MIM keys… though its possible i’ve had some come through my hands.
one nice thing about the internet- if people don’t like what a manufacturer is doing, word spreads like wildfire, and manufacturers DO listen.
Thanks folks. For the record, I did try a couple of searches and didn’t come up with anything. I tried “LMT MIM” and “LMT BCG” and didn’t find anything. Since I just found out what MIM stands for I did a find on “Metal Injection Molding” and found the thread that discusses this.
Cut and pasted email reply to a member on TOS from Ryan Johnson of LMT
Just emailed LMT and received a response stating that they still use MIM carrier keys. According to the email they stand behind this process stating:
" Please know that all products we offer are made to Mil-Spec specifications per our government contracts and are tested to meet or exceed the requirements mandated by those contracts. " " However our current contracts call out for the gas keys that we use and it has been tested to over 125K without any kind of failure. We did copious amounts of testing with the new keys with the military and have found that what we use now is superior longevity and durability wise to the forged keys we used to use."
“All I can say is trust in what we are doing as the President of this company will not put his name behind anything that isn’t tried and true or doesn’t meet our quality control standards.
Please let me know if you have any other questions or concerns.”
Thank you,
Ryan Johnson
Sales Representative
Lewis Machine & Tool Co.
1305 West 11th Street
Milan, IL 61264
Phone: 309.732.9527
Fax: 309.787.2636
Email: johnsonr@lewismachine.net
I don’t understand or agree with LMT on the MIM keys, the AR15 BCGs, or the carbine buffer decisions, either. They are no longer a contender for my dollar. My next project is a Bravo Co middy on a DD lower.
And to answer the OP’s question, yes I have a new LMT carrier with an MIM gas key I am using it in a MK18 MOD0 10.5" upper that will see heavy use.
Am I worried about it failing? NO.
Who designed these gas keys? Engineers at LMT that have forgotten more knowledge about the platform and manufacturing firearms than we will ever know.
What the likely point of failure on a 10.5" carbine? The gas port, the bolt lugs, the cam pin hole in the bolt (which is still shot peened, MPI, and HPT), and barrel throat.
Please, I would love someone to point out someone, ANYONE who has had a failure of an LMT MIM gas key.
Disclaimer- I am a happy LMT user, though I only have about 3000rds through my
LMT with the MIM gas key. No complaints or failures so far.
Also, I agree with decodeddeisel, while LMT may not supply complete rifles like Colt and FN, they supply many service parts and add-ons to the military.
His statement is valid in the context of which it was stated. What AR-15/M16 components that are made by LMT are used in USGI M4s and M16s?
Blanket, generic statements from a manufacturer such as “used by our military customers” don’t mean anything. How do you define “military customer”? That could mean anything. That could mean the military of Peru, etc. That doesn’t necessarily mean the United State military.
I don’t see the point of buying an LMT anything with Bravo Co. offering better products at a better price, and Colt 6920s selling for $1100-1200.
My own personal experiences with LMT uppers, and the experiences of the guys I know who received LMT MK18s, have not been stellar. LMT CS leaves something to be desired, too.
Yes Scotty I have read enough of your posts to know that. Still though the LMT 10.5 does have an NSN, and it was issued.
Yes, LMT supplies M203s and the SOPMOD stock.
Tells me they know a thing or two about manufacturing small arms and small arms components for the military.
His statement is valid in the context of which it was stated. What AR-15/M16 components that are made by LMT are used in USGI M4s and M16s?
Blanket, generic statements from a manufacturer such as “used by our military customers” don’t mean anything. How do you define “military customer”? That could mean anything. That could mean the military of Peru, etc. That doesn’t necessarily mean the United State military.
Scotty, I know you have a “thing” for LMTs but the fact of the matter is that their had an NSN (albeit a temporary one), and they were issued. This would indicate to me that they have their shit together.
When I bought my BCG the LMT was in stock at the time, BCM was not.
My own personal experiences with LMT uppers, and the experiences of the guys I know who received LMT MK18s, have not been stellar. LMT CS leaves something to be desired, too.
If you don’t mind, would you share your experiences with LMT?
Likewise would you share the extent of your less than stellar experiences with LMT’s customer service?
Look guys let me make it clear, I am not some LMT fanboy. To me they offer a superior product as a good price. I probably would have gone with a BCM BCG if it had been in stock, and similarly I would have gone with a Colt 10.3" upper, but it was literally nearly 2x the cost of the LMT.
Still though the LMT 10.5