Is an M4 barrel really actually truly 14.5" long?

[TED]

I found a dimensional drawing online that claims that it is really only 13.85". I know sometimes things can be "nominal" or "proximal", and so forth.

Is an M4 barrel really actually truly 14.5" long?

m4barr10.jpg

[georgeib]

It is when you include the barrel extension.

[mig1nc]

I believe the ATF measures from the closed bolt face.

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[GH41]

I believe the ATF measures from the closed bolt face.

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Correct.

[Todd.K]

First, that is not the drawing that M4 barrels are made with...

Second, you failed to add the portion of the barrel that the extension threads over. So that adds .620 to the length.

[markm]

First, that is not the drawing that M4 barrels are made with...

Second, you failed to add the portion of the barrel that the extension threads over. So that adds .620 to the length.

Maybe it's LWRC's crayon spec sheet.

[Clint]

True, but the "nameplate" length is generally measured from the breech face.

I believe the ATF measures from the closed bolt face.

[mig1nc]

True, but the "nameplate" length is generally measured from the breech face.

Thanks, Clint. I always learn something new.

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[jpmuscle]

Maybe it's LWRC's crayon spec sheet.

You still hate them don’t you?


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[MegademiC]

There was a thread a while ago about this.
A lot are near 14.5 but most were a bit longer.