View Full Version : Lmt carrier = noticeable difference?
I understand the engineering behind it, but when will the upgrade be noticeable as opposed to just improved efficiency which should lead to longevity?
Just on a suppressed Sbr?
What about a precision 16”?
vicious_cb
12-09-18, 20:16
I understand the engineering behind it, but when will the upgrade be noticeable as opposed to just improved efficiency which should lead to longevity?
Just on a suppressed Sbr?
What about a precision 16”?
Its not about efficiency, the LMT enhanced carrier is about solving the issues of 14.5" and 16" carbine gas systems. If you arent running those gas systems then you probably dont need to be using one.
It actually works very well with suppressed SBR's.
Its not about efficiency, the LMT enhanced carrier is about solving the issues of 14.5" and 16" carbine gas systems. If you arent running those gas systems then you probably dont need to be using one.
Difference between a Colt BCG and LMT EBCG. Requires one less on the gas setting of an SLR AGB on a Noveske 14.5 middy with A5H3. Reliable lock back. Functions from UMC 55 gr to M855.
So, what I'm reading here is that a mid-length would not need such a enhanced BCG? I just ordered a Colt BCG for an eventual middy 16" carbine I hope to build.
So, what I'm reading here is that a mid-length would not need such a enhanced BCG? I just ordered a Colt BCG for an eventual middy 16" carbine I hope to build.
I think you might be mixing up quality and enhanced. No doubt many will agree that the Colt is a quality BCG, the LMT carrier has several changes/improvements that your Colt BCG won't have:
here is an article with pretty good pictures: http://smallarmssolutions.com/home/lmt-enhanced-bolt-carrier
I'd like to get one but the cost compared to my normal toolcrafts on sale keeps me on the bench.
OK, yes there are improvements that any rifle/carbine could benefit from. Specifically carbine length gas systems but any length gas system too. But I'm not SOCOM and I don't, as much as I would like to have, their budget or shooting schedule. So, I'll just stay over here and be happy with my Colt BCG... I will be using a LMT receiver so there!
I can't imagine that there would be any benefit to using an LMT Enhanced carrier in a 20" barrel with a rifle length gas system.
Bolt yes, carrier no.
vicious_cb
12-10-18, 15:12
It actually works very well with suppressed SBR's.
Definitely, I've been following other users experiences in the other LMT threads with suppressed SBRs. My previous post was more for the not so savvy general audience since it seems it does require some tinkering based on the barrel length, gas port and buffer weight combo.
I need to try one of Pappabear's LMT carriers in my suppressed SBR. It's ported down, but still snappy as hell. I'd love to see if the carrier makes a difference.
I can't imagine that there would be any benefit to using an LMT Enhanced carrier in a 20" barrel with a rifle length gas system.
Bolt yes, carrier no.
Agreed from what I've read. Bolt can be used for any barrel length. Carrier is another story.
My understanding is that the EBCG is specifically for carbine length gas systems. Not that it wouldn't function on a mid-length (I have a 14.5" BCM mid-length that it works fine on), but it was designed for a carbine gas system and it's earlier unlocking.
A side benefit is that the carrier has the extra vent holes so it has ever-so-slightly less carbon buildup.
The longer the barrel, the less you'll notice a difference with carrier. In the 16in I've used it is still great with an SLR gas block though, you can turn down the gas a bit more, but not as much as in an 11.5in. I haven't tried it in a 20in, but I'd imagine the difference would be even more slight, but probably still noticeable if you have a suppressor.
The bolt is just always a straight up upgrade.
Am I right to assume the LMT bolt would fit right in a Colt carrier?
That is correct, their bolts work with any carrier, and their carrier works with any bolt basically.
Hammer_Man
12-11-18, 12:11
I have two rifles with carbine gas systems, one has a Colt bcg and the other has a LMT E-bcg. Between the two, there is the slightest difference in perceived recoil impulse, with the LMT being ever so slightly softer. To be honest, it may just be placebo... Can anybody else confirm my perceptions?
Can anybody else confirm my perceptions?
Comparing two barrels, even from the same manufacturer, isn't very scientific... Two different manufacturers is really stretching it.... with port size, bore diameter variances, chamber/leade variations, etc.
No benefit in longer barrels with controlling gas, but there is no downside either. The more overpassed your gun the more noticeable the difference. The bolt is a work of art and is a nice upgrade to any gun, but nothing you would feel. Just function and longevity.
is it worth it......, its an expensive upgrade.
PB
jerrysimons
12-12-18, 09:54
In a nutshell the LMT e carrier requires less work to extract a spent case due to increased lock time/ chamber pressure blow down time (less friction of case walls pushing into the chamber walls due to higher chamber pressures). This translates to more reliable extraction and requires less gas drive (even with the additional expansion chamber vents) to function. The down side is increased rearward carrier velocity, which by itself may actually increase felt recoil. This is why most here have found it good to pair the LMT e carrier with the A5 buffer system which has a better spring rate and options for heavier buffers to help slow the carrier. Heavier buffers also provide additional reliability owing to slower carrier speeds for the magazine spring to present the next round and increased momentum driving the next round into the chamber.
I can’t say as heavy mass systems are really the way to go if your chief concern is recoil reduction and utmost reliability in different environments isn’t a priority, lightweight gaming systems have the advantage there.
Really the answer is to pair it with an adjustable gas block like an SLR. That solves both issues and allows its strengths to shine.
jerrysimons
12-12-18, 22:45
Really the answer is to pair it with an adjustable gas block like an SLR. That solves both issues and allows its strengths to shine.
The A5 improvements stand alone from gas regulation. Some have durability reservations about adjustable gas blocks though SLR surely is the benchmark. Personally I think a properly ported barrel coupled with the LMT E carrier and the Vltor A5 system is the ticket. Though gas regulation alone does not fully offset the quickened unlock timing the heightened pressure curve of shortened gas seystem causes. The LMT E carrier therefore still moves the unlock timing in the right direction with a delaying effect on unlock timing in shorter gas systems even when coupled with gas regulation.
I don't want to get this thread sidetrack, just note that fears of AGB durability are unfounded when using quality ones like SLR, Superlative, and Seekin's detent.
Back to the topic at hand, I just to clarify I wasn't suggesting using an AGB and INSTEAD of the A5+LMT Enhanced BCG. I was suggesting using an AGB with both of them. Each offer their own improvements, and the AGB allows both to be maximized and their drawbacks minimized. While you can get some of that improvement with a properly sized gas port, you cannot get all of it. But I can understand not wanting to change a gas block to something you need to remember and think about in some settings for some people.
everready73
12-13-18, 07:28
I don't want to get this thread sidetrack, just note that fears of AGB durability are unfounded when using quality ones like SLR, Superlative, and Seekin's detent.
Back to the topic at hand, I just to clarify I wasn't suggesting using an AGB and INSTEAD of the A5+LMT Enhanced BCG. I was suggesting using an AGB with both of them. Each offer their own improvements, and the AGB allows both to be maximized and their drawbacks minimized. While you can get some of that improvement with a properly sized gas port, you cannot get all of it. But I can understand not wanting to change a gas block to something you need to remember and think about in some settings for some people.
I wouldn't quite say they are unfounded. I have read of multiple issues with adjustable gas blocks from those manufacturers just this week on TOS. Mainly with the screws that adjust the gas. I wouldnt use an adjustable gas block unless i absolutely needed to
I don't want to get this thread sidetrack, just note that fears of AGB durability are unfounded when using quality ones like SLR, Superlative, and Seekin's detent.
Back to the topic at hand, I just to clarify I wasn't suggesting using an AGB and INSTEAD of the A5+LMT Enhanced BCG. I was suggesting using an AGB with both of them. Each offer their own improvements, and the AGB allows both to be maximized and their drawbacks minimized. While you can get some of that improvement with a properly sized gas port, you cannot get all of it. But I can understand not wanting to change a gas block to something you need to remember and think about in some settings for some people.
What will you get using an AGB that you wouldn't with the proper sized gas port?
jerrysimons
12-13-18, 11:09
What will you get using an AGB that you wouldn't with the proper sized gas port?
I think variability to account for ammunition and environmental variables at the expense of increased complexity, parts failure potential, or user error risks. I can see the place for them in the commercial market especially with good designs like SLR but they have no place in the military where ammo supply is a known variable and guns have to be soldier proof.
I wouldn't quite say they are unfounded. I have read of multiple issues with adjustable gas blocks from those manufacturers just this week on TOS. Mainly with the screws that adjust the gas. I wouldnt use an adjustable gas block unless i absolutely needed to
Interesting, can you link? I've never seen or heard of issues with the newer SLR, SA, and Seekins blocks beyond the occasional "it got stuck" thing. Which I've never had because I put a drop of slip 2000 EWL every 1000-2000 rounds or so and go one click up and down. But I've also intentionally let the SA block go for 4K and it didn't get stuck, just a bit tight to move. Like I said, it is something you need to remember, but that is about it. I'd read positive reviews of the SA blocks on lightfighter as well. But if there are actual problems I'd certainly like to read about them.
MistWolf, that can depend on the design of the block. I'd suggest watching this series of videos (https://www.youtube.com/watch?v=UwHA9pvkgYA). But to give a quick summary: you cannot possibly have proper gas port sizing for every environment, load, buffer combination, rifle condition (dirty, clean, lube, etc), and suppressed/unsuppressed use, let alone combining these factors. This is especially true as the barrel gets shorter. That is why we see so many different barrels optimized for so many different loads, environmental conditions, and suppressed use. P&S had some good interviews detailing that makers like FN will even modify the port size if they know it is going for a competition in say Alaska vs. Arizona. What is optimal for M855A1 won't be for Tula, let alone can on/can off, and so on.
The adjustable gas blocks let you optimize for just about every possible situation and combination, and do so on the fly. As long as the gas port is cut just a bit big you can have the same rifle eject both PMC Bronze and hot Israeli M193 both at 2:30 with a few clicks on the gas block. Same with going hot/cold, suppressor on/off, gun dirty/gun clean and so on and so on. There are other large benefits as well, like being able to use significantly lighter buffer+spring+BCG combinations to lower perceived recoil and muzzle movement (and extreme example being what the 3gun people do) not to mention the overall weight of the rifle. It also puts less strain on the BCG since it delays unlock (and all the other benefits of this). A side benefit of this that most people don't think about is that AGBs actually make suppressors far more pleasant to use, cutting noise down by 3-7db to the shooter's ear, and cutting down on blowback; example here (https://www.youtube.com/watch?v=BNWVo76DwRs).
So there are a ton of advantages for very little drawback. Think of it like the switch from fixed stocks to adjustable stocks. And/or the switch from irons to optics. Same kind of process, and some kind of decision if it is worth it to the end user to KISS or go for the performance enhancement new technology offers.
Now I do want to be clear, yes plenty of rifles can work ok in a combination of conditions, but none will do so as well as or in as many as a rifle with an AGB that gets adjusted. Also, the gain is smaller (though still there) for those who will have the fewest variables change, so folks always using 1-2 types of similar pressure ammo with the rifle in similar conditions always suppressor or unsuppressed and so on (so basically most of .mil and most departments). Furthermore, an adjustable gas block isn't for everyone (or even most, can you imagine boots with 40 gas settings) but there is plenty of performance to pick up there if you are willing to.
Back on topic, the reason you get additional benefit combining the LMT E carrier and the AGB is that they compound the delay of unlocking and the AGB can help reduce the bolt speed (all else being equal). Hence my suggestion to OP.
Interesting, can you link? I've never seen or heard of issues with the newer SLR, SA, and Seekins blocks beyond the occasional "it got stuck" thing. Which I've never had because I put a drop of slip 2000 EWL every 1000-2000 rounds or so and go one click up and down. But I've also intentionally let the SA block go for 4K and it didn't get stuck, just a bit tight to move. Like I said, it is something you need to remember, but that is about it. I'd read positive reviews of the SA blocks on lightfighter as well. But if there are actual problems I'd certainly like to read about them.
MistWolf, that can depend on the design of the block. I'd suggest watching this series of videos (https://www.youtube.com/watch?v=UwHA9pvkgYA). But to give a quick summary: you cannot possibly have proper gas port sizing for every environment, load, buffer combination, rifle condition (dirty, clean, lube, etc), and suppressed/unsuppressed use, let alone combining these factors. This is especially true as the barrel gets shorter. That is why we see so many different barrels optimized for so many different loads, environmental conditions, and suppressed use. P&S had some good interviews detailing that makers like FN will even modify the port size if they know it is going for a competition in say Alaska vs. Arizona. What is optimal for M855A1 won't be for Tula, let alone can on/can off, and so on.
The adjustable gas blocks let you optimize for just about every possible situation and combination, and do so on the fly. As long as the gas port is cut just a bit big you can have the same rifle eject both PMC Bronze and hot Israeli M193 both at 2:30 with a few clicks on the gas block. Same with going hot/cold, suppressor on/off, gun dirty/gun clean and so on and so on. There are other large benefits as well, like being able to use significantly lighter buffer+spring+BCG combinations to lower perceived recoil and muzzle movement (and extreme example being what the 3gun people do) not to mention the overall weight of the rifle. It also puts less strain on the BCG since it delays unlock (and all the other benefits of this). A side benefit of this that most people don't think about is that AGBs actually make suppressors far more pleasant to use, cutting noise down by 3-7db to the shooter's ear, and cutting down on blowback; example here (https://www.youtube.com/watch?v=BNWVo76DwRs).
So there are a ton of advantages for very little drawback. Think of it like the switch from fixed stocks to adjustable stocks. And/or the switch from irons to optics. Same kind of process, and some kind of decision if it is worth it to the end user to KISS or go for the performance enhancement new technology offers.
Now I do want to be clear, yes plenty of rifles can work ok in a combination of conditions, but none will do so as well as or in as many as a rifle with an AGB that gets adjusted. Also, the gain is smaller (though still there) for those who will have the fewest variables change, so folks always using 1-2 types of similar pressure ammo with the rifle in similar conditions always suppressor or unsuppressed and so on (so basically most of .mil and most departments). Furthermore, an adjustable gas block isn't for everyone (or even most, can you imagine boots with 40 gas settings) but there is plenty of performance to pick up there if you are willing to.
Back on topic, the reason you get additional benefit combining the LMT E carrier and the AGB is that they compound the delay of unlocking and the AGB can help reduce the bolt speed (all else being equal). Hence my suggestion to OP.
In other words, an AGB doesn't work better with the LMT E-Carrier and A5 RE than a properly sized gas port, it just lets you experiment with a wider variety of variables. I know this to be true because I have various length barrels, suppressors, A5 REs, AGBs and barrels that are properly. I find the A5 and LMT work just as well with the properly ported barrels as they do with a properly tuned AGB. I don't need an AGB to get the advantages of the LMT E-carrier or the A5 RE system.
I'm not against using an AGB. Using an AGB taught me a lot about what makes for a properly tuned AR.
I'm using an SLR AGB. I had some trouble with it and SLR was great helping me get it sorted out. Now it has rock solid reliability and it's earned my trust. But there are potential failure points.
I mostly agree MistWolf, but I think experimentation is the wrong word. Rather the rifle can simply handle a much larger variety of circumstances and reap the reward of being optimized for them. You don't by any means have to use an AGB as you said, but the more you want to do with the rifle, the more helpful it will be to have one. In other words, it is hard for me to think of a civilian who is this into shooting sports/defense that is only going to shoot one to two similar pressure loads, only ever suppressed or unsuppressed, in a small array of temps and rifles conditions, and then gets a gas port cut specifically for that. Still as you say it is a potential failure point, so someone needs to "opt in" to it, just like an optic is a potential failure point that you'd opt into changing the batteries for. Not to mention the huge benefits when running suppressed with an AGB as the videos above show.
I'm glad SLR helped you out, I've yet to use their CS but I've heard good things if I have to!
Experimentation is exactly the right word. Having an adjustable gas block lets the shooter play around with different combinations to find out what works and what doesn't. Once the shooter finds out what works, why change it? Simply to experiment, that's why. Changing ammo often means a change in POI. That means the rifle has to be sighted in again costing time and money. So why change ammo when you already know what works? Only two reasons I can think of- Economy and efficiency. Economy means we like to shoot as cheaply as possible so we can shoot more. Efficiency means we want ammo that does a specific job well, either better terminal ballistics or improved precision. Usually a balance between the two.
Sometimes the shooter is concerned with ammo availability, but that's a unique circumstance. During the Great Ammo Drought, sometimes I had to shoot what was available because selection was thin. During that time I didn't have to worry whether or not my AR would shoot low pressure Tula or the equivalent, because that's the cheap stuff. Cheap stuff flies off the shelf faster than I can click the "Add To My Cart" button.
Once I got my AR with the AGB dialed in through experimentation, I never had to change the setting again. Unless a gas leak developed somewhere. With the properly gassed ARs, they are forgiving enough that switching from Federal 5.56 ammo to Remington 223 ammo didn't cause any kind of hiccup. I have two suppressed shorty uppers and shoot them almost exclusively suppressed. I paid good money for my suppressors. You best betcha Hong Kong believe it I'm gonna use'm! I basically stick to using Federal 5.56 ammo because of economy and availability. It gives me good enough precision out of my shorties and carbines to get the job done, basically keeping all shots in 2.5 moa. This is shooting in temps from 110 degrees down to as low as 5 (sometimes lower). Experience has taught me to find a load that works in your rifle and stick to it.
The difference between the batteries going flat in my optic and a small part in the AGB going bad is that I can pick up batteries at the local gas station.
I'm not against the AGB. I do like to experiment. Experimenting with the AGB and different buffers opened my eyes to the importance of getting the gas right and how buffers affect function, felt recoil and shot recovery. But when it comes to shooting, what works is sticking to what works.
What it all comes down to is the A5 RE, green spring and LMT E-Carrier with a properly sized fixed gas port has a wide span of operation with soft recoil. At least it does in my experience.
For changes in ammo, potentially that can be true (although I'd argue a lot of people switch between very low and very high pressure loads for plinking--->serious use). But as I mention there are many, many more factors that change more drastically and with less control. Suppressed and unsuppressed is probably the best example, but there are others like 115f degree summer ---> -25f degree winter, and clean and lubed--->dirty and no lube. I can tell you for all of these situations my gas block can be turned up and/or down to hit optimal function, and when I do I get less perceived recoil and muzzle movement, and if suppressed it is less noisy and gassy once done properly. Not to mention it just functions in general, which say a build optimized for a suppressor with hot ammo may not do when unsuppressed with weak ammo. That is my experience.
I will also say the things 3 gunners and others are doing with lightweight BCG+spring+buffers is pretty cool, and generally require AGBs.
I have no idea why someone would worry about switching from suppressed 5.56 ammo to unsuppressed weak ammo.
My properly gassed AR runs in hot and cold temps, clean or dirty. The only thing is, the one that's unsuppressed is always shot unsuppressed (it has a pinned A2) and the one that's suppressed is always shot suppressed. That's whether I rung them with the A5 lower or carbine RE lower; regular carrier or the LMT E-Carrier.
3 gun ARs are another animal altogether. That kind of tuning results in a narrower span of operation and as such, usually need an AGB for optimal performance.
vicious_cb
12-14-18, 03:11
I would highly suggest getting a properly ported barrel over an adjustable gas block on any AR you plan on using for Duty/SD. No matter what the design is, that adj. gas block will eventually either adjust itself or stop being adjustable if it didn't already throw its innards 10 yards down range.
Well I guess we'll just agree to disagree slightly on that one point Mistywolf, really just around optimization vs. raw function and in what conditions.
vicious_cb, do you have some evidence of unreasonable failures in SLR, SA, and Seekins blocks? I haven't encountered anything beyond QC/getting it stuck because you don't use it (as I mentioned before) myself or online. Now I don't have any super high round counts, but I have an SLR block closing in on 10k without issue. Seems they'd last at least as long as the barrel.
I understand where and when the reputation comes from, but it seems like the latest rendition of the technology has ironed a lot of the past problems out. Seekins is even shipping their SP10M (the mil/LE version) with their detent adjustable gas block (https://www.youtube.com/watch?v=9Mh3P0WjRx4). Adjustable pistons have existed forever with little to no issues as well.
Again I'm not trying to say everyone SHOULD put them on a duty rifle, I'm just curious about failure rates for my own uses.
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