After owning and shooting all 3 bbl lenghts, I am likin the 18/18.5 in bbls over the others as a go-to rifle.
An M1A Scout with an SEI Vortex direct connect flash hider/ gas lock front sight is very close in OAL to that of a Socom, retains very close MV to that of a 22in bbl M1A/M14, ( 20 to 50fps in comparison), and does away with any proprietary components that the Socom utilizes. It also reduces muzzle flash by a great margin compared to the std fh, and especially the Socom MB.
http://www.smithenterprise.com/products03.01.html
Here is a comparison pic of an M1A Bush rifle ( flash hider = same length as a Scout's MB)....... next to an SEI "front end"...........................
Note: The version pictured above is an SEI gas lock (hooded) HK style front sight.
The "dovetail" version in the pic above will allow the use of any of the various front sight units out there.
My Socom, along with most of my 22in tubed M14/M1A's went to family members.
Note: My Socom( now my oldest boy's) started out in life as a Socom II, but the rail heavy front end had to go. Makes for a decent little rifle now, as she is sitting in a GI synthetic stock along with std HG.
Note: The rifle with the SEI front end above sports an 18.5in chrome lined bbl, while the M1A-A1 with the std castle nut system sports an 18in SAI non chrome lined tube...... but the longer bbl is still shorter in comparison due to the SEI components.
I use both for hog/deer hunting. From the close in fast movers and for longer shots out around the 400 yd mark...so far.
11B