I have been reading about the big boy gas tubes and is there any advantage to having one on a Semi auto AR?  If so where do I find one?  And people that do please post your thoughts.


Thanks in Advance

No advantage unless you run a short barrel in full auto, IMHO.

I was thinking about one for my Oly. Its an 11.5" and will FTE ocasionally on higher pressure. ie.Q3131 etc. But will not do it at all on lower pressure stuff like Wolf etc. This has been a perplexing problem for me but I think its a gas problem, and that fat tube may let chamber pressure subside enough to allow better extraction, and allow the gun to run more reliably. I am going to try one for myself to see if this corrects the problem. These short guns can sometimes run faster than the magazine can..   John

Hey keep me up to date on what you find out when you try!  Thanks.... anyone else?

My feeling exactly.

For some unknown reason the Fat Boy gas tube has become one of the "Must have upgrades" (like many others) for semi-autos on this site, even though it may in fact make your Carbine LESS reliable.

Go figure!

I disagree, I think they make the carbine MORE reliable IMO.  They aid in extraction problems associated with carbine length barrels, and make the felt recoil smoother and reduced. The aid in extraction also helps when your cases are more difficult to extract due to fouling, dirt, or melted laquer.  The effect is more pronounced with the shorter barrels, and also has the additional desireable effect of slowing cyclic rate on F/A fire.

That said, if you don't have problems with extraction, I would not blow the money on one.  I use them on three of my carbine uppers, but those are for my M16.  I don't bother with them on my 16" semi's.  There simply isn't enough benefit (though there is some) to justify the cost IMO.

Yep, I have had a hell of a time with FTE on my 11.5". Guy at the range said " just get a longer bbl short ones just dont work" . BS I said. Ive seen 7.5" bbls run fine. I narrowed it down to a gas problem after trying some  low pressure Wolf. Not ONE problem on the cheap ammo. Im gonna get a fat boy and Ill betcha I can shoot any .223/5.56 W/O a problem.. John

Read this thread before you go with a gas tube fix on a shorter barrel:

[url]http://www.ar15.com/forums/topic.html?b=3&f=118&t=170410&w=searchPop[/url]

Extractor lift issues are relevant because a certain amount of pressure at the chamber keeps the case against the bolt as the extractor lifts off and comes back down. The Fat Boy gas tubes might solve your too much pressure issue; but if they reduce chamber pressure to the point the empty case does not have enough push to stay on the bolt when the extractor lifts, you'll still have FTEs.

Also, check some posts here. Some have mentioned that multiple reliability mods (fat boy, one-piece gas rings, etc.) have actually decreased reliability and I bet the extractor lift issue explains a lot of that.