Midlength system really more reliable?

[Wondering Beard]

From what I have read on various sites, the midlength gas system is at least theoretically more reliable than the carbine gas system but something has been nagging at me.

If I understand what I have read correctly, the longer gas tube provides for a more uniform and smoother gas flow leading to a supposedly more reliable cycle while the shorter system in the carbine provides for a more violent one.

Considering that the carbine system has had its bugs pretty much worked by now, the main difference it has with the midlength system is the violence of action from the shorter gas tube and thus how hard it is on internal parts.

Wouldn't it then be more accurate to say that the carbine gas system is not so much less reliable but less durable, as parts may have to be changed more frequently?

Also, wouldn't it be fair to say that in extreme conditions (extreme fouling, extremly cold or hot weather etc..) that the very violent action of the carbine gas system may be more likely to move the impediments (dirt, sand, ice etc..) inside the action whereas the smoother midlength system might not be as capable?

Or am I just totally off on all of this and need to start reading again?

[Paulo_Santos]

Reliable isn't the right word. It should be durable like you wrote. Take a 16" barrel with a midlength and a 16" barrel with a 16" barrel with a carbine length gas system, if gassed properly, they will both work very well. Keep in mind that I've been shooting mostly the 6.8 SPC in the last 4 years (over 20k rounds) so the 5.56 recoil isn't that big of a deal to me compared to the 6.8. In theory, the midlength one should be slightly softer shooting since the dwell time is shorter. For most practical purposes, I don't see much of a difference. For gamers, the softer shooting is preferred for the faster shooting. I have a 16" midlength which is a very nice shooter, but that is not the first thing I would look for in a 16" barrel unless I was going to use it for 3-gun or other games.

[Wondering Beard]

Thanks Paulo.

Just to be clear, I don't intend to purchase another AR any time soon. My question was more out of interest in the hows and wherefores of ARs.

I still do wonder if the "violent" action in the carbine gas system might not actually be an advantage when dealing with more extreme conditions and thus, in a sense, more "reliable" than the midlength gas system.

[Paulo_Santos]

Makes sense what you are saying. As the AR gets dirtier, it will get sluggish, so the harder cycling of the carbine gas system can actually help out.

[rob_s]

Mike Pannone did a test and article on running the M4 without lube and IIRC it went for thousands of rounds. I believe that the more violent impulse of the carbine gas system is what made his gun run as long as it did as dirty as it got.

However, I still think that the mid-length gas system has merit, and I do believe the theory that it isn't as hard on the rifle. I resisted it for years and finally gave in when the BCM mid-lengths finally came back after a long hiatus. I also recently got a T&E 14.5" mid-length gas BCM rifle, another version I was resistant to and which I have now come to really appreciate.

[TehLlama]

In a lightweight setup, going to a midlength makes a larger noticeable difference in shooting sensation. Properly lubricated the middy isn't going to give up much, and certainly be able to fire more rounds without a hitch than anybody is willing to lug on their person, but the carbine system is certainly viable, and I'd agree that the overgassed nature of the carbine system doesn't hurt when carbon is building up, but either will keep running with some lube.

[Dualspringfields]

So which is better? Mid or Carbine. Im think of getting another upper. I already have two carbines. One is a DPMS that will be the one getting replaced. Wondering which one would be better. Not brand,but llenght. Mid or Carbine.

[Paulo_Santos]

I'd get the midlength in a 16" barrel.

[Dualspringfields]

Thanks

[Keebsley]

It seems that the trend nowadays leans towards middy's. For my next upper, I'll be snagging a BCM 14.5 middy.

[TehLlama]

When the BCM 14.5" Middy LW's come out, I'll have to sell some stuff to make room for it. I can't wait for that, a 9.0 Lite Rail or VTAC/TROY 9.0, and EAG package to come out.

On a 14.5" it's an honest toss-up which is better, and will depend on what application you have in mind, but a 16" middy is becoming popular for a reason.

[rob_s]

In a 14.5-16" carbine I can only think of a few reasons why I'd choose carbine-length gas over a mid-length at this point:

Extreme weight reduction. For a woman, child, or disabled person with arm-strength issues. The longer gas tube, and further forward placement of the gas block, adds weight and shifts that weight further forward.
Parts availability. If I were in LE and using a personally-owned carbine in a sea of department-issue carbines I might want to stick with a gun that uses all the identical parts as the armorer keeps available.
Replicating an issue gun. Were I in a situation where I had an issued carbine for work, I believe I would replicate that issued firearm as closely as possible for my personally-owned gun if I was using said gun in training.


Otherwise, and after a long period of resistance, I have become totally sold on the mid-length gas system in barrels 14.5"-16".

[markm]

I can't see any reason why I'd ever buy another 14.5" barrel with a carbine length gas system.

[prizz23]

It seems that the trend nowadays leans towards middy's. For my next upper, I'll be snagging a BCM 14.5 middy.

Amen to that!

[peabody]

i just putt together a dissy' 16 incher with middy gas' and yes.i like it alot.
it is a little smoother.
my cmmg barrel is a ADCO trimmed down lightweight.
looking forward to the MOE rifle length handguards.
so far using a plum crazy lower, the A.R.M.S. model 41-B front sight is just awsome , .. :)
everything is very light.
may turn out to be my favorite AR.
alto ? im still in love with my A1 20''
nothing beats an old slickside :)
peabody.

[tac40]

I was hoping Ken Elmore from Specialized Armament would chime in here. I have several Colt carbines and never had any issues. I like the mid-length and have one in a 6.8 upper. I wonder why Colt hasn't moved in this direction.
"If it ain't broke, don't fix it" maybe a reason.

"This expression has been popularized from the idea that any attempt to improve on a system that already works well is pointless, and may even be detrimental. Reportedly it originated in the United States in the 20th century from Bert Lance who, as a government official, was quoted in May 1977 issue of Nation's Business[3] as saying, "If it ain't broke, don't fix it." Lance's advice, according to William Safire, "has become a source of inspiration to anti-activists."

Thank you Wikipedia.

[peabody]

just re-read this thread....

for what it's worth. my neighbor has a DPMS dissipator 16'' barrel, with rifle gas.
very soft shooting. runs like a champ' we've shot severl thousands of rounds through his, nary a problem.

it just keeps on chugging away, no matter what we feed it.

someday im going to HAVE to get a 16'' with rifle gas. i just love the way his shoots.

peabody