Who dropped the big cash?  Worth it? If you're holding out, why?

Been using one for almost a year.  Very reliable and no problems - a delight to clean.  That said, don't expect dramatic performance changes, basically the bolt and carrier are designed to give more longevity and reliability to the system, you won't notice the difference unless you shoot a lot of ammo.  

had one in the gun for about two month, it has been a good piece upgrade.  the chromed bolt did not clean up as well as I expected.

The bolt is plated with electroless nickel. And by the way I got the chance to clean mine as it came from the factory looking like 40rds had been fired to test the B/BC.  The bolt appeared to clean quickly (as chrome plated bolts generally do) even though the fowling had been left on the BBC for longer than 5 days the Bolt wiped clean with CLP without scrubbing witha wire brush or anything like that [normally neccesary for std Bolts].


I have one but I have to wait till paperwork clears on my SBR to use it.  That could be a while.

[b]What does it do?:[/b]



electroless nickel bolt has added lubricity for smoother feeding when dry or near dry.

Rounded bolt lugs have more resistance to shear when a standard RAS is used and lots of pressure is exerted on the foregrip during firing (not a problem with FF RAS's)

The lugs also have a radius milled into their side surface that appears to be some sort of self-cleaning groove to allow the bolt to tolerate more debris (like sand) in the barrel extension.

The bolt is slightly thicker supposedly to reduce bolt breakage accross the cam pin recess.

The Extractor should not give a user trouble for the life of the weapon (no need to replace springs as they are good for 1,000,000 cycles.)

The third hole in the bolt carrier gives greater dwell time when used in 10.5's and 14.5's smoothing cycling characteristics. This also gives the brass more time to contract off the chamber walls and thus gives more reliable extraction esspecially when heavily fouled.

There is also a Oil hole in the BC which as far as I have been able to realize could only do three things:

1 allow the rear of the bolt to be oiled without dissassembling the BC assembly.

2 allow the user to cool the bolt and gas rings with a shot of CLP in emergency situations where high rate of fire is believed to endanger the gas rings which are crutial to proper functioning.

3 Allow the user to inject a shot of clp to get the dirtiest part of the bolt soaking before the user even goes home or back to the unit or whatever to break his weapon down to clean.

[/b]Horik reports that using his in a LMT 10.5 (it failed to cycle 5 times when he was breaking it in) he put the LMT Bolt into a std Colt carrier and fired some rounds and then put the LMT Bolt and carrier back together and fired that again- after which it began to cycle flawlessly) He noticed a big difference in recoil spike over a standard carrier, the empties ejected more consistently.

It sounds to me like the gas rings that come with the carrier are a little tight and need about 50-150 rds to smooth up (this is purely my assumption though).

This is really not fair test though as the carrier was really designed for the M4 barrel and not the very closely gas regulated LMT barrel which is known not to cycle with PRI gas tubes. Throwing a third gas hole into the mix is a lot like adding that PRI gas tube.

Mine is a LMT 10.5 as well but most of the time it will have a KAC M4 QD sound suppressor attached so it will get a lot more gas through it's tube than it was designed to- allowing the bolt carrier to correct the excessive recoil spike that I will be creating by adding the suppressor.

[b]These improvements may sound marginal to you but for others who try to get maximum perforemance out of their weapons the LMT SOPMOD II B BC is a great idea.  [/b]


Sorry if I just bored the living crap out of you : )  

I know I sometimes elaborate too heavily.

Knight's Armament is coming out with a similar product.  I am one of the hold outs who wants to see which is better before I pick one up.  My current bolt/carrier work just fine at this point.

I thought you posted that your rifle was malfunctioning with these parts installed?

[url]http://www.ar15.com/forums/topic.html?b=3&f=12&t=164878[/url]

Am I wrong on this?

If I am not and since you are one of the "looked up to members" on this site for your knowledge and expertise, how in good conscience could you recommend said parts to the average member?

.......I think Chen swapped the standard gas rings (in the LMT) with a Macfarland and had considered that to have been the problem.  I am speaking from what I remember of that thread though!

I love mine.......

If the small amount of friction added from the McFarland gas rings makes the difference between function and nonfunction then what does that say? It says your running on the edge of reliability. I have watched that (LMT) thread with much interest as to why so many folks are so captivated with parts that may actually REDUCE the reliability of their SEMI-AUTO (since these parts are tuned for the FULL-AUTO) rifles just because they are hailed "the latest and greatest" by the experts of this site? But then again ChenLee may also have the PRI FAT gas tube and Heavy buffer in conjunction with these LMT parts (All of these parts are designed to slow the Carrier in an atempt to enhance a FULL-AUTO's longevity AND reliability).      

hey AKM,
maybe i can help clear that up as i was with chen that day.  the reasons for the jams in that particular incident had nothing to do with the bolt or gas system. it was the combination of a standard barrel extension installed in an upper with M4 feed ramp cuts.  the barrel extension overhung the feed ramps, creating a lip for the bullet tip to hang up on. when i took chen's LMT carrier and stuck it in my M4 to test it, it had no probs.  hope that helps.

another thing i noticed about the LMT carrier is that the inside of it where the bolt sits is relieved - the chamber is expanded.  
i've only had about 300 rnds thru my LMT carrer/bolt - not much i know, and that was used during a brand-new upper break-in.  no stoppages of any kind, but then, i might have gotten the same result with my regular carrier and bolt.
cheers,
MM

I'm sure most people are interested in this new equiptment due to it being an upgrade attempt and the fact that most people have not experienced reliability problems with them....

I was'nt stating the Mcfarland ring was the problem I said I remember Chen writing it may be a cause.......Now you know it was not!!

Any failure I had was in a 10.5" upper totally new with all brand new parts in the entire weapon.  After a breakin period it is the best BCG I've owned!  Yes the standard is fine but it is a free market!

"If the small amount of friction added from the McFarland gas rings makes the difference between function and nonfunction then what does that say? It says your running on the edge of reliability. I have watched that (LMT) thread with much interest as to why so many folks are so captivated with parts that may actually REDUCE the reliability of their SEMI-AUTO (since these parts are tuned for the FULL-AUTO) rifles just because they are hailed "the latest and greatest" by the experts of this site? But then again ChenLee may also have the PRI FAT gas tube and Heavy buffer in conjunction with these LMT parts (All of these parts are designed to slow the Carrier in an atempt to enhance a FULL-AUTO's longevity AND reliability). "

Yes sometimes combining a LMT B/BC with a PRI gas tube and AAC buffer is going to cause malfunctions, but I would rather have a couple trips out to the range spent getting my rifle running and have a rifle that isn't:

ripping nearly stuck cases from the chamber (causing extractors to wear out)

pouring excessively high pressure gas into the bolt causing gas rings to melt prematurely

spiking excessively causing bolts to shear at their cam pin hole

experiencing more recoil than neccassary and in general not allowing the user to place shots with maximum precision on tartgets as fast as possible.

Case in point: LMT uppers have a ROF of around 650RPM brand new
850RPM with a KAC suppressor attached
somewhere near 850 RPM at 10,000rds.
somewhere near to 650RPM at 10,000rds after putting in a PRI gas tube.

these parts (though some combinations will not function properly) will optimize the performance of any ar-15. They allow you to basically adjust your gas system.

just attaching the sound suppressor makes it act like it has an eroded gas port. In this case the LMT B/BC would help by reducing stress on the weapon allowing excess gas to escape the bolt rather than overheating the bolt and melting the gas rings. (and from Horik's experience it seems like it will be reliable without a suppressor attached so it doesn't compromise reliability.)

The AAC buffer will smooth functioning and bring down ROF so the gun will take longer to overheat in full auto.

full auto at 850RPM with a suppressor attached will destroy a weapon far quicker than at 600RPM.

[b]I'll bet KAC could make a better BC now that they have the ability to see their competitors product and all it's inovations and probably reverse engineer every feature into theirs and maybe add a few in the process (coughCHEAPBASTARDS). All kidding aside though it will be interesting to see if KAC can better the LMT product (LMT seems to have some amazing talent concerning their ability to machine metal and perform many operations for less cost than you would think would be mandatory to make a profit)[/b]

Good post GeenO!  There was a pic floating around here somewhere of one of the KAC enhanced bolt mods I think.  It was the drop in version not requiring their bbl. extension, whcih their other one will.  It looked to have the same extractor set up more or less.  That being the Lobster tail extractor system.  That was the only difference from the standard bolt I could see from the pic.  Perhaps there is more but only time will tell.  It also appeared to have the standard lugs ie., non-beveled!  I agree that LMT is up to par with anything out there.......perhaps better than most!

AKM,

You are right, I did have problems with the carrier, but that is because the LMT upper with M4 cut and the Diemaco barrel had no cuts, it also had problem with the Fatboy and McFarland gas ring. but independently, the LMT is flewless, I have dropped the carrier into a standard M4 and it functioned time after time.  It is all the experiment I am working with gun that have cause all the problem I mentioned in the past thread.  


My M4 runs with LMT carrier with standard gas ring and fatboy and H buffer with out any hiccups.  This is my result after many range testa and french speaking sessions.

Thanks for the report ChenLee.

A little too much American thinking: If one is good, then two must be better. [:D]