I've looked it up and I can't really tell which is better.  Any help would be appreciated.

I would also like to know.

The bottom line is the mid-length fixes many of the issues caused by the shorter carbine gas system.

If you are going with a 16" barrel I highly recommend a mid-length.

"Better" is probably not what you're looking for.  They have strengths and weaknesses.

The carbine-length gas system is shorter, gets higher pressure gas from the gas port and the impulse is sooner in the pressure curve, and thus pushes the bolt carrier back faster and more abruptly.  It works well, and is well suited for short barrels.

The mid-length system is longer, so it gets gas that's higher pressure than in a rifle-length system, but lower than a carbine system.  This gas is also produced midway between carbine and rifle points in the pressure curve so it's less harsh than a carbine but harsher than a rifle.  The gas pushes the carrier back less quickly and less abruptly, so it's easier on your parts (and shoulder to some degree).  it works well and is well suited for the 16" barrel.

I am convinced that the midlength is a better system, but the carbine has been around a long time and can be very reliable.

i have two middy's and an 18" rifle ...no carbines

Quoted: The bottom line is the mid-length fixes many of the issues caused by the shorter carbine gas system. If you are going with a 16" barrel I highly recommend a mid-length.

+1 carbine gas system on a 16" is pointless. Mid-length is superior and looks better to boot.

If the bbl is less than 16" then carbine is cool.

Thanks for the replies.  I've got 2 5.56's in CAR lenght and a 6.8 on order with the same setup, but I think I'll see about getting the 6.8 in a mid-length, since it's gonna take about 12 weeks anyway.  I'm getting ready to build a 5.56 from the ground up and was looking at another CAR length, but not now.  Thanks for talking some sense into me.

Quoted: Quoted: The bottom line is the mid-length fixes many of the issues caused by the shorter carbine gas system. If you are going with a 16" barrel I highly recommend a mid-length. +1 carbine gas system on a 16" is pointless. Mid-length is superior and looks better to boot. If the bbl is less than 16" then carbine is cool.

However, if you have a 14.5/14.7" barrel, you'll do just fine with a middy gas system too.  I had Steve at Adco re-profile my 16" HBAR to a lightweight and shortened to 14.7" w/pinned A2 FH and it runs like a top.

Quoted: Quoted: Quoted: The bottom line is the mid-length fixes many of the issues caused by the shorter carbine gas system. If you are going with a 16" barrel I highly recommend a mid-length. +1 carbine gas system on a 16" is pointless. Mid-length is superior and looks better to boot. If the bbl is less than 16" then carbine is cool. However, if you have a 14.5/14.7" barrel, you'll do just fine with a middy gas system too.  I had Steve at Adco re-profile my 16" HBAR to a lightweight and shortened to 14.7" w/pinned A2 FH and it runs like a top.

Doesn't that look like a bizarre dissipator?  Post pics, COSteve!

I had a RRA CAR4 (hbar) and a STAG M4 profile barrel.  I liked them both and they did the job without complaint.

I recently sold my CAR4 upper and replaced it with a 16" mid length.  I have read enough about them to know that is what I want.  I almost went with the middy on the STAG, but wanted the lighter M4 barrel.

I haven't fired the middy yet, but I'm sure I won't be dissapointed.  For looks, I think I have the best of both worlds with those two rifles, but I do like the look of the midlength a little more.

Quoted: Quoted: Quoted: Quoted: The bottom line is the mid-length fixes many of the issues caused by the shorter carbine gas system. If you are going with a 16" barrel I highly recommend a mid-length. +1 carbine gas system on a 16" is pointless. Mid-length is superior and looks better to boot. If the bbl is less than 16" then carbine is cool. However, if you have a 14.5/14.7" barrel, you'll do just fine with a middy gas system too.  I had Steve at Adco re-profile my 16" HBAR to a lightweight and shortened to 14.7" w/pinned A2 FH and it runs like a top. Doesn't that look like a bizarre dissipator?  Post pics, COSteve!

Not at all.



And at 7.65lbs as shown (w/o mag) it is very light and nimble.

Quoted: Quoted: Doesn't that look like a bizarre dissipator?  Post pics, COSteve! Not at all. img.photobucket.com/albums/v726/Coloradoglocker/100_0103.jpg And at 7.65lbs as shown (w/o mag) it is very light and nimble.

Indeed, not odd looking at all.  I had expected the gas tube length difference to put the FSB farther forward.  That's what I get for imagining without having real numbers handy...  Thanks for the picture.

I have a 16" carbine, a 16" middy, and a 14.5" middy. I would not buy anther carbine unless it was a 10.3" or an 11.5"

In a 14.5-16" barrel the middy has the following advantages:

Smoother bolt stroke
Slightly softer recoil
Less wear and tear
Longer sight radius
More rail space if you install a rail system
Better balance
Better looks, IMO

Would it be possible to have the barrel reconfigured from a CAR-length gas system to a mid-length system?  If so, what's the normal cost?

Quoted: Quoted: Quoted: Quoted: Quoted: The bottom line is the mid-length fixes many of the issues caused by the shorter carbine gas system. If you are going with a 16" barrel I highly recommend a mid-length. +1 carbine gas system on a 16" is pointless. Mid-length is superior and looks better to boot. If the bbl is less than 16" then carbine is cool. However, if you have a 14.5/14.7" barrel, you'll do just fine with a middy gas system too.  I had Steve at Adco re-profile my 16" HBAR to a lightweight and shortened to 14.7" w/pinned A2 FH and it runs like a top. Doesn't that look like a bizarre dissipator?  Post pics, COSteve! I love the look of a 14.5"/7" on a middy. I don't like a 16"bbl on a carbine gas system... too much bbl sticking out... Not at all. img.photobucket.com/albums/v726/Coloradoglocker/100_0103.jpg And at 7.65lbs as shown (w/o mag) it is very light and nimble.