You made a good choice. Quality Carbine >> low end midlength.
For 16" barrels midlength does give you less gas (marginally cleaner, less recoil impulse), but a carbine of the same length will probably run a bit longer while dirty.
Barrel material, chamber dimensions, and crown for the barrel, and quality of BCG components are far more relevant to function and accuracy than gas port placement. DD Mk5 - you did good.
عندما تصبح الأسلحة محظورة, قد يملكون حظرون عندهم فقط
کله چی سلاح منع شوی دی، یوازي غلوونکۍ یی به درلود
"Being able to do the basics, on demand, takes practice. " - Sinister