what is the advantage the fat boy?  disadvantages?  Im wondering because i have a 16in carbine with a carbine length gas system, and i am going to put a LaRue 7.0 on it.  since im going to have remove the front tower it might be a good time to up grade the gas tube.  is it worth it?
Thanks in advance

Remman

I asked the gunsmith that removed and installed my barrel about my gas tube. He said that it's something that doesn't usually wear out (unless of course you're ruining it by doing many full auto mag dumps sequentially). Unless it's broke, don't fix it. I've never had any problems with mine in about 6000 rounds. I am sure the extractor spring is getting close to being ready for replacement though.

i have run the fatboy gas tube and it made a difference in limited circumstances.  you gotta ask yourself is there a need to change the gas tube?  
if your rifle functions 100% with the std tube, stick w/ it.....
the fatboy is a higher volume car gas tube that slows the velocity/lessens the gas pressure that actuates the bolt carrier, and it is the answer to a couple problems related to shorty ars in full auto mode.....shorty barrels (especially 10" or 11.5") have very little barrel length after the gas port, and this makes reliable functioning of the rifle an iffy proposition if the gas port isn't drilled to the correct size.  if the port is too small, then short dwell time between when the bullet passes the gas port and the exits the muzzle  is not enough time to fully pressurize the tube and finally and completely actuate the bolt opening.....hence short stroking and the bolt wont pick up a fresh round when cycling.
to compensate, some barrel makers open the gas port more to compensate and thus allow more pressure to enter the tube for the given dwell time......finding the ideal gas port size is the big question, but its easy to open it too much.  if the gas port is opened too much, then the gas pressure may be excessive and there may be too much pressure and the bolt gets opened rather violently....a condition called "bolt bounce" results where the gun is basically beating itself up.  also, in fa mode this higher bolt velocity equates to much higher rate of fire........

so fatboy came out to remedy the problem of excessive gas port size.....whether it was orginally drilled too large, or if the gas port has eroded over time due to thousands and thousands of rounds thru the barrel.  the larger volume of the tube somewhat dissipates the high pressure and slows the gas pulse to lower levels (kinda "simulating" the gas pressure level of a longer gas tube) while still maintaining reliable function.  also, since the pressure is lowered, then in fa mode, the rate of fire will also drop.  

so you have to ask yourself if you have any of the problems with your setup....oversized or eroded gas port? bolt bounce? excessive rate of fire in fa?  then you may need a fatboy.....hth

Quoted: ... so you have to ask yourself if you have any of the problems with your setup....oversized or eroded gas port? bolt bounce? excessive rate of fire in fa?  then you may need a fatboy.....hth

true but what if someone wants to have less recoil and stay on target better for double taps?

Quoted: Quoted: ... so you have to ask yourself if you have any of the problems with your setup....oversized or eroded gas port? bolt bounce? excessive rate of fire in fa?  then you may need a fatboy.....hth true but what if someone wants to have less recoil and stay on target better for double taps?

That is why I have a Fatboy on my M4 carbine.

i have one on my m4 and it works as good as the old tube. i think it does make rapid fire a little more controlable

are there any reliability issuses with different ammo.  i think i recall some one saying that 55grn didnt work as well.  

Remman