Question about m4a1 and AR barrel profiles

[Milf Dots]

In reference to 14.5 and 16 inch carbines, is there a chart that shows the most common barrel profiles and O.D./ dimensions for issued m4a1s and civilian ARs? I'm also curious to know what the heaviest issued m4a1 barrels are, and if that profile is often used on civi ARs. Is it safe to assume the barrel profile terminology/labels used are fairly universal? TYIA

 

[longshot2000]

loaded question, but a pretty easy answer, or so I think.

M4 rifles typically have what is known as a Government profile or an M4 profile to the barrel. At one point, the SOCOM profile, or heavy profile was introduced, with the main purpose being to hold an M203 grenade launcher better than the standard M4 profile. Both barrels are the same from the FSB to the muzzle, and share the characteristic slot whether the M203 strap would fit. Under the handguards, the M4 pattern is thin and comes up to 0.75" at the gas journal. The SOCOM barrel is thick under the handguards, and usually has vertical cuts, refrerred to as "M203 cuts" to support (better) the grenade launcher.

I hope I hit on the highlights. You cannot tell one from the other with handguards on.

 

[Steel head]

There’s a few charts from various manufacturers showing common AR barrels.

 

[Molon]

A Visual Library of AR-15 Barrel Profiles