m4 inner barrel length

[Whitt]

What inner barrel length would i need for a 12" m4 outer barrel?

[Lozart]

Standard (14.5") M4 has a 363mm inner barrel. So about 300mm should be right.

[BrightCandle]

293mm is the usual 12" inner barrel length. You can always measure your own of course but that is the common short barrel length that I know about for the close quarter guns.

[Whitt]

Would the length be good or outdoor usage?

[straffham]

A lot of people use 12" barrel guns in woodland quite happily, its more down to your hop rubber with regards to range/trajectory. If your hop is good then yeah its fine.

[M_P]

Would the length be good or outdoor usage?

The length makes no difference so nothing to worry about

[Whitt]

my maths got me to about 240 mm .... :/ I just dont want anything sticking out of my barrel

[M_P]

How? 12 inches is 304mm.

[Whitt]

i may have mixed up 3 and 2

[BrightCandle]

The inner has some bearing on accuracy, there is evidence for that. The optimal inner barrel length for maximum accuracy is about 450mm. The difference between the usual 350 and 300 inner barrel is going to be very slight and to be able to measure the difference you would need to get a lot of other aspects of the gun working perfectly to even notice. Its a minor aspect of accuracy as far as I can tell from the research I have done.

[Whitt]

so get a 300 mm barrel?

[jcheeseright]

yes, 300mm will be fine.