Gas tube length?

[Jbones1983]

So I'm down to the last few parts for my AR build and I'm a little confused about what length as tube to get. I have a 16" barrel, M4 profile that needs a .750 gas block.

So am I looking at a Mid-length gas tube?

 

[Golddiggie]

I believe it all depends on where the port is on the barrel.

 

[canislupy]

Assault Rifles For Sale - Mid Length Vs. Carbine Length Gas System | Assault Rifles For Sale

They have a nice picture illustrating.

 

[Golddiggie]

Sounds like if you didn't get a barrel that has the port further towards the muzzle, you'll be getting a carbine length setup. My new DPMS uses a carbine length tube. Not sure what I'll do for the next rifle upper I build.

 

[noxin]

I thought all m4 barrels were carbine length?

 

[ntomsw]

It all depends on where the hole is drilled on the barrel.

Typically a 14.5" would be a carbine length, and 16" would be a mid length gas system. That is not always the case though. My 2 AR 16" barrels are carbine.

 

[colt_fan]

If it is a true M4 profile, it will be a carbine length gas system.

The M203 cutout of the M4 profile prevents it from being a midlength gas system.

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[dans]

Take a ruler and measure from the gas hole to the back of the barrel. Then look at the picture in the link CANISLUPY provided. It should be fairly obvious which length you need based on that.

 

[jasons]

If it is a true M4 profile, it will be a carbine length gas system.

If it were a "true M4 profile" it wouldn't be 16"

 

[colt_fan]

If it were a "true M4 profile" it wouldn't be 16"

Civilian facsimile M4 profile.

The point being is that with the M203 cutout it is not possible for it to be a midlength gas system.

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