The bolt is not ION coated I have never see that in any statement from LMT regarding the bolt?
If you read Bill Alexanders statement in this thread it explains the feature's of the bolt and carrier better than any other statement I have ever found.
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As an engineer by trade it always impresses me to see detailed information such as what was posted here. Another reason why I enjoy this board.
I am interested in the long term reliability and parts sustainability of the entire 'system'. To this end I have adopted a mid-length gas system on a 14.5 barrel (BCM BFH). I have noted decreased bolt carrier speeds which in my opinion reduce stress on the moving parts in the system and therefore should increase parts longevity.
I am interested in the bolt due to the technical advantages and relatively non-existent disadvantages but am also considering the enhanced carrier as well.
Question is: Given a BCM BFH mid-length gas 14.5 barrel, H buffer and standard Colt carbine spring (with standard receiver extension) utilizing a wide range of available ammunition and weights how will the enhanced LMT carrier perform?
I use one in a 14.5'' LMT with a carbine spring and H-buffer.
I have about 4K through it give or take. Mostly XM193 & XM855
but I have put 100rds of wolf steel case 62 grain and 600 rds of 55 grain PMC Bronze. Wolf seems to be close to the edge but I didn't have any malfunctions with it. I had to replace the buffer spring around the 2K mark it fell bellow spec. Still going on the factory gas rings and they still pass the gravity check.
Huh, this thread raised it's head. I say after all this time, mine (the bolts) have run great on everything. Short long fat skinny barrels. I've not had problems.
You could justify the extra cash on the coating alone they clean real easy. I have to admit, I enjoy LMT coolaid.
That's what I was thinking. I was thinking that I could compensate for that by using the AR-15 BCG rather than the M16 BCG (lighten it up) and go to a carbine buffer vice the 'H' buffer (further lighten the mass). But in the long run I may just go with the bolt and forget about the carrier.
Any ideas how a 16" mid length with the enhanced carrier and bolt with a Vltor A5 stock would compare to a 14.5" mid length? Witch one would be "softer shooting"?
The carrier was optimized for the carbine gas system using a 14.5" -16" barrel. Anything other than that and you are outside LMT's specifications. So if it doesn't work for you outside of that there is nobody to blame but your self :sarcastic:
Now after saying that I have used it on a 10.5" barrel with carbine gas length system. With a suppressor attached it would lock the bolt back on the last round with out the suppressor it wouldn't lock the bolt back on the last round. I wouldn't bother with it on a middy gas system I think it would be too much of a good thing and you would be likely to have short strokes.
How does electroless nickel compare to nickel boron?
It's a good finish but in no way does it come close to the performance of NIB. I doubt you would be dissatisfied with electroless nickle though. If it wore off or you don't like it then just get it coated in whatever you want. It's still better than phosphate.
I think the main benefit of the enhanced LMT bolt is the mechanical design and not the coating. Things like the stronger steel, and the stress relief cuts, etc. are what makes it that much better / stronger.
The difference between M16 and AR15 carriers is so slight that it can be ignored, perhaps 1/3 ounce.
You should already be running a standard carbine buffer with a 14.5" midlength so there's nothing to be gained from switching from an H buffer to a standard carbine buffer.
Sorry for the slight necropost but since this discussion seemed to revolve primarily around the use of an enhanced bolt in 5.56 (with the exception of a 7.62x39 post) I though I'd raise the question of how much this design would benefit the 6.8 platform?
If I'm not mistaken, LMT uses this BCG exclusively on their 6.8 rifles and I don't think they would be a company that would use it if it weren't warranted when they could use a less expensive BCG if possible. They seem for the most part no-nonsense IMO.
I know it's hardened steel but does anyone know if it's Carpenter 158 or 9310?
What's the advantage of the enhanced bolt itself? Only the extractor and the cuts on lugs? Other than that would you say it's about equal to a quality bolt itself?
It's also hardened, nickel plated, and has less material taken out under the extractor like a standard bolt. Pics with the extractor removed are here.
https://www.m4carbine.net/showthread.php?t=1130
I've been trying to research the LMT enhanced bolt, I'm strongly considering buying one for my DDM4V1 LW (carbine length), I'm strongly sold on the utility of the bolt, but what about the carrier, do you think the DDM4V1 would benefit from the carrier or would it potentially cause issues?
Also of relevance, Hornady TAP 75gr. .223 pressure is what I have for defensive ammo.