LMT ar-15 bolt carrier GTG?

[Barron1]

Hi guys,

New to the forums - forgive me if this is covered somewhere already. I just purchased a complete LMT MRP rifle. I thought all LMT carriers were m-16. I should have checked the chart more closely. Mine came with an ar-15 carrier. I trust LMT, but I know an M-16 carrier is preferred. Should this concern me? I was hoping some members here had experience with carriers like mine and could give some feedback.

Thanks much,
B

[Eric]

Don't sweat it. The difference really is minimal and LMT is top notch. Shoot it, a lot!

[markm]

This whole 16 carrier thing has gone full retard. As long as the carrier shrouds the firing pin collar, it's fine. The only other difference would be a negligible weight variance.

[Barron1]

Thanks guys. That's what I wanted to hear. I've been after an MRP for a while so I'm looking forward to it.

B

[lamarbrog]

This whole 16 carrier thing has gone full retard. As long as the carrier shrouds the firing pin collar, it's fine. The only other difference would be a negligible weight variance.

This is totally true. I am pretty snobby when it comes to AR parts... but FA or SA carrier is pretty much the very definition of inconsequential. I have both, and aside from the fact one doesn't work when I attach it to an M16 lower half, they function the same.

LMT makes a great product.

[Paulo_Santos]

This whole 16 carrier thing has gone full retard. As long as the carrier shrouds the firing pin collar, it's fine. The only other difference would be a negligible weight variance.

Damn, where have I been? Is the M16 carrier the latest must have thing? I haven't been following "The Chart" for years now, so I'm not "in the know" anymore. LOL.

I wonder if people even know the reason for the M16 carrier in the first place.

[AR-10]

Should this concern me?

No. I have an old Colt 6920 (serial number under 1000) that came with an open-bottom carrier.

I've been asked why I don't swap it out for an AR-15 or M16 carrier, but don't see the point.

It's never, ever caused an issue.

[FortTom]

Deleted - double posted...

[FortTom]

Damn, where have I been? Is the M16 carrier the latest must have thing? I haven't been following "The Chart" for years now, so I'm not "in the know" anymore. LOL.

I wonder if people even know the reason for the M16 carrier in the first place.

I didn't get the memo about the retarded M16 carrier craze either. But I can say this. My latest build (I should actually say assembly) is based on an LMT lower and LMT upper. It uses the M16 carrier, simply because I chose Spikes NiB bolts for it and another, and they happen to be M16. I can say that the LMT is one of the smoothest an coolest running AR's I've ever owned, or used while in the military. Maybe it's just dumb luck. I don't think the weight difference is significant, however at cycling speed, even a small amount of wieght could be amplified, just no way to answer that question. My personal guess is either would perform just fine, with negligble differences, but again, that's just a guess on my part. But please, when the "retarded craze" is over, someone send me the memo so I can dump both bolts....just kidding...lol....[:)]

FT

[Barron1]

My only concern was weight. I read (in conjunction with the chart I believe) that the m-16 carriers are preferred b/c they are heavier and increase lock time after firing some making extraction more reliable. Looks like this is not as big a deal as I thought. Funny how when you get an idea in your head it stays with you regardless of your understanding (or lack of). I was bothered way too much when I saw the non-m16 carrier. I almost dropped 88 bucks to replace a GTG carrier just b/c of something I read a while back. Glad you guys cleared it up.

[Paulo_Santos]

My only concern was weight. I read (in conjunction with the chart I believe) that the m-16 carriers are preferred b/c they are heavier and increase lock time after firing some making extraction more reliable. Looks like this is not as big a deal as I thought. Funny how when you get an idea in your head it stays with you regardless of your understanding (or lack of). I was bothered way too much when I saw the non-m16 carrier. I almost dropped 88 bucks to replace a GTG carrier just b/c of something I read a while back. Glad you guys cleared it up.

A heavier buffer will do the same thing.

[TangoSauce]

A heavier buffer will do the same thing.

Thanks for posting where I was going to go with my post.

Essentially, the only time I've personally found it desired to have a F/A bolt carrier was when I had a carbine that was cycling fast. I replaced the bolt carrier with a F/A bolt carrier and it alleviated the symptom but did not fix it. I then replaced the spring with a Sprinco and started using an H buffer. Rifle ran fine after that with either carrier. Instead of spending loot on the F/A I could have probably replaced the buffer and/or spring for much cheaper.

[Paulo_Santos]

I apologize for the previous posts about the M16 carrier function. Obviously the primary job of the M16 carrier is to hit the top of the auto sear, which is holding the trigger. The other part that I wrote, was supposed to be a secondary function, as I was told, but I don't even believe that is true after reading more about it and doing some research on it, but I did email the instructor to clarify exactly what he told us, because the way he explained it, it made perfect sense.

So I deleted the other posts because I didn't want this thread to turn into a shitstorm, which would have been my fault anyway.

[markm]

My only concern was weight.

Yeah... the weight variance is negligible. The buffer is where you want to nail down the bolt speed.

[Barron1]

Thanks markm. Should I ever consider a heavier spring to address bolt speed, or leave it all up to the buffer? I run a car buffer in my 2 middy's right now with standard springs. Have heard H would be good to, but I don't want to lose the ability to function reliably with cheaper ammo. Sorry if this takes the thread from the original topic.

[Paulo_Santos]

Here is the response from Mike from Colt. The Auto Sear controls the timing, not the cycling, as I incorrectly wrote before. Obviously, the Auto Sear and the M16 Carrier go hand in hand.


The purpose of the auto sear is to keep the hammer cocked during full auto fire,* until the bolt is locked into battery and ready to fire to cartridge.* Remember the "J. Geils effect" I was referring to?**Because of the chamber pressure (52,000 psi) if the M16 fires out of battery: it will blow your face off; (the title of one of*J. Geils'*albums in the early 70's).* Due to the high cyclic rate of fire,* the M16 has a greater*opportunity to fire out of battery on full auto.**The auto sear has nothing to do with the rate of fire of the M16.* The auto sear only works when it is on automatic.** It is a*timing and safety device*device:* it times the hammer to drop (automatically) after the bolt is in battery and it does so safely so your face is not blow off (too much) while firing* a high cyclic fire weapon.** Bill Murray would call it a helpful safety device!
*
Remember the disconnector only works in semi;* the disconnector MAKES semi auto fire.
Bypassing the disconnector makes full auto fire.*
The auto sear only works in (full) auto; it makes full auto safely, it keeps it from firing out of battery and you losing your head over the affair!

[landshark]

Its really a non-issue as far as the weight is concerned. Just go look at all the folks who run light-weight BCG's and low mass buffers in competition. With or without an adjustable gas block, these guns run just fine. For them, they want fast lock times to ensure that they won't outpace the gun to make sure that shot to shot time is minimized.

As far the whole M16 vs AR BCG, as every one else has said, a heavier buffer would "fix" any issues that might come up. If extraction issues are your concern, then I would make sure to look under the extractor of your bolt and make sure that is has the small (typically) black little plunger inside of the spring, this will increase the spring tension and increase extraction. Even then, if your weapon fails to rip the brass from the chamber take it to a gun shop and ask them to drop gauges in the chamber. BCG Speed has less to do with extraction, then proper chamber specs and extractor tension.

I would stay away from different spring weights. Just my opinion

[Barron1]

It came with black insert, factory LMT spring (I think five coil) AND crane o-ring. I will probably remove the o-ring unless I have problems, since gun is mid-length. Thanks.

[M. Gale]

Here is the response from Mike from Colt. The Auto Sear controls the timing, not the cycling, as I incorrectly wrote before. Obviously, the Auto Sear and the M16 Carrier go hand in hand.

I don't work for Colt but I did stay at the Holiday Inn Express last night...

It's mechanically impossible for an M16 to fire out of battery as a result of a miss timed hammer strike. The firing pin isn't long enough to break the plane of the breach face until the bolt is locked.