This is sort of a weird comparison. A modified 1301T in an almost unusable configuration against the M4 in only the fixed length (ape index) versions. The M4 has three factory stock configurations, four of you count the fixed length telescoping stock. The adjustable stock M4 SBS is shorter than the 1301T with SGA stock. What would be interesting is an adjustable length stock for the 1301T and A300UP.
I may not be getting the point, BUT, if you (Centerfire) are saying the 1301T with SGA stock is too short to be usable, I probably disaqgree. It's easier for most 'adult armed' folks to use a shorter stock than it is for the shorter armed person to use a standard-length stock. (Hope that reads the way I wanted)
Adding nothing to the conversation since 2015....