Full length gas tube vs. midlength. - Page 3
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Old 06-21-2011, 06:16 PM   #21
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I think we have a nomenclature difference here, perhaps I am using the wrong recognized term.

Stoner's AR-10 Rifle System, which was the intial design in 7.62 before the scaling down to 5.56/.223, was a gas operated, 508mm (20 inches) barrel length system.

The scale of the point on the 20" where the gas port was placed was in relation to the length and the pressure of the round in question (7.62) on prototype 4 as 1 thru 3 were adjustable gas systems.

When the AR-10 was scaled down, the same criteria was used as the round was smaller, thus the pressure less, and that is what I have known as a "rifle length" gas tube.

It would appear that "carbine length" is the preferred term. I had always attributed that to being on the length of the tube on the rennovated XM177, the short barreled versions. The relation to the receiver was modified because of the shorter barrel, but the scaling was roughly the same.

The comment about Stoner was in relation to the scaled length from the receiver to the gas port, not that Stoner designed a 16" as that was merely a spin off of his design.

I apologize for the wording as it is appears in doing some reading on several informational sites about the origins of the M-16 I had the terminology wrong. Mea Culpa.

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Old 06-21-2011, 06:57 PM   #22
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No big deal, I get tripped up trying to explain stuff myself all the time. don't sweat it Brah
I tried to find a better pic to illustrate the differences, but this is the best I could snatch off the interwebz...
All are 16 inch barrels with standard FSB gas blocks (Top to Bottom)
Carbine
Mid
Rifle gas systems

Compared to a standard 20" Rifle length gas upper


I was kind of trying to illustrate how the mid length was created to keep the gas port location on a 16" barrel at close to the same ratio as the original soft shooting rifle length had with the 20" barrel.
Maybe I just confused myself....
Lol best I can do!

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Old 06-21-2011, 08:23 PM   #23
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Nope. That actually meshes with what I always thought I was saying.

I saw "carbine" as the carbine rifle, the short barreled XM177, so that carbine picture on top would have the shorter muzzle right off the end of the sight ramp/gas block. Thus if I needed a replacement gas tube, it would be the much shorter tube.

With the "rifle length", in my mind, it was the scaled distance from receiver to gas block betwen 7.62 versus 5.56 so while it was closer to the receiver, it was in relation to the intial "rifle" design, which was further out on the 7.62 barrel.

I have been thusly educated and now realize my terminology was wrong.

Apologies once again.

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Old 06-21-2011, 09:29 PM   #24
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So I was reading about Carbine vs. Mid Length and found that mid length will be less harsh on the BCG on a 16" barrel. Is it absolutely necessary to have midlength? If so I will probably have to delay my ar build and wait for PSA to have those mid lenght complete upper in stock again or go with BCM which cost quite a bit more.

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Old 06-21-2011, 09:34 PM   #25
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Quote:
Originally Posted by luan87us View Post
So I was reading about Carbine vs. Mid Length and found that mid length will be less harsh on the BCG on a 16" barrel. Is it absolutely necessary to have midlength? If so I will probably have to delay my ar build and wait for PSA to have those mid lenght complete upper in stock again or go with BCM which cost quite a bit more.
I feel the midlength is the best way to go in a barrel 16" to 14.5".
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Old 06-21-2011, 09:44 PM   #26
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I feel the midlength is the best way to go in a barrel 16" to 14.5".
Man but I hate that long looking handguard. I guess I'll wait a bit on my build then. Hopefully PSA will have their midlength back in stock soon. Waiting on my new credit card anyway.
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Old 06-21-2011, 09:45 PM   #27
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Originally Posted by luan87us View Post
So I was reading about Carbine vs. Mid Length and found that mid length will be less harsh on the BCG on a 16" barrel. Is it absolutely necessary to have midlength? If so I will probably have to delay my ar build and wait for PSA to have those mid lenght complete upper in stock again or go with BCM which cost quite a bit more.
In my opinion I also feel the mid is the way to go, but No its not "absolutely necessary".
In fact when I bought my last AR I wanted a mid-length 16" but I ended up buying a carbine length because I found a great deal on one close to home.
Have had no problems with the carbine length being a little over gassed and unless you go through tens of thousands of rounds a year,every year, I doubt you will either. There are tens if not hundreds of thousands of 16" carbine gassed AR owners that are completely happy with their rifles.
I did end up adding a heavy buffer to mine to slow the bolt speed down a bit. It didn't need it, but I like the way it feels better now.
Also i plan on, when time and money allow, trying a heavier M16 style carrier to see if I like that feel even more.
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Old 06-21-2011, 09:51 PM   #28
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Man but I hate that long looking handguard.
Then you will really hate mine
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Old 06-21-2011, 10:00 PM   #29
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I kinda fall in line with Gatekeeper. While the mid-length is commonly preferred and definitely most "user friendly", the Carbine on a 16" barrel has been used with minimal issues for years, they shoot great and are arguably most reliable. Throw a H2 in the tube and you're GTG!

Now if you want a bit of compromise and still to stick with rifle (original) length gas system, use a 18" barrel. The feel is the same as my 14.5" mid-length (thing of beauty) and shoots circles around a 16" carbine as far as accuracy.

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Old 06-21-2011, 10:01 PM   #30
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In my opinion I also feel the mid is the way to go, but No its not "absolutely necessary".
In fact when I bought my last AR I wanted a mid-length 16" but I ended up buying a carbine length because I found a great deal on one close to home.
Have had no problems with the carbine length being a little over gassed and unless you go through tens of thousands of rounds a year,every year, I doubt you will either. There are tens if not hundreds of thousands of 16" carbine gassed AR owners that are completely happy with their rifles.
I did end up adding a heavy buffer to mine to slow the bolt speed down a bit. It didn't need it, but I like the way it feels better now.
Also i plan on, when time and money allow, trying a heavier M16 style carrier to see if I like that feel even more.
Hmm thing is i will probably sharing this ar with my shooting buddies as well so we might go through quite a few rounds. We go shooting almost every Sunday. Don't know how much we're going to shoot .223 since it costs a bit more than 9mm and 22lr but I think we'll maining be shooting this AR if I finish it (I think we would do about 500 rounds or so a month at least). Do you think carbine will be fine for me? or should I settle for the midlength? I just really hate the ugly long looking handguard on them unless I get a hand rail which make my build blow out of budget T.T
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