If the NEW SOCOM M4 BARREL is heavy under the HG's and has the cut out for the M203 in front of the sight doesn't this negate the entire purpose of the M4 profile?   The M4 barrel profile was originally designed only to meet the DOD requirement that all rifles accept an M203.

Jay

The new one, from the pics I've seen, is not a true HBAR barrel. It's medium-heavy and is tapered the whole way down to the end of the barrel. Apparently some units I guess needed the extra thermal mass due to sustained automatic fire.

themao

The new M203 mount does not touch the barrel, so the new SOCOM M-4 barrel will not have ANY cut outs...the final config is as of yet undecided, and will be left for the vendors to work out...it may even be Fluted! This is my best guess; my new Bushmaster M-4 has their 14.5' heavy barrel with fluting...hope I'm right!

I like the fluted barrels.  It is my understanding that fluting is all around the best way to go.  
Because if MSTN is selling KAC RAS FF tubes the rifle will not accept an M203 without complete disassembly anyway.

Jay

The current M4A1 bbl profile is the heavy M4 bbl - it has a cut out before the fsb and in front like the original M4's - the 'new' cut out is just vertical cuts to allow the M203 mounting ears to slide over it.

I had posted some pics of this compared to the original but since Photpoint went down they are not net accessible.

The NEXT SOCOM block carbine is not yet determined - but it would appear to be a FF sytem and for M203 mounting odds have it using the Diemaco M203A1 mount which attaches to the RAS/SIR lower rail via M1913 rail mounts.

I'd sure like to see some pics of that SOCOM barrel.

Glad to see the US-MIL finally learned what I already know - a fluted, heavy bbl. is the way to go!

Hmm, this is very interesting. A fluted heavy barrel mounted in a free floating forend.

And the antis say that the private shooting world contributes nothing to national defence anymore. This sounds like a 3-gun shooters wet dream.

Will they use cryo-hardening too I wonder?

Any more happy news on this development?