barrel/handguard...

[bdub712]

looking at getting a DD upper recevier, DD 14.5 pencil barrel and a DD lite rail, but my question is..what length of handguard would be recommended? If i go with a FSB does that make a huge impact? I'm not sold on having an FSB...the idea behind this build is to make it light...

[sewvacman]

For a carbine length gas system I believe 9" is required to cover up the GB.
Midlength go up to 11"

I just got a 13" VTAC extreme and OMG am I impressed with the difference in weight/balance. Extremely light even though it's so long. If you have a chance check out the vtac/troy handgaurds before you buy another brand. I've only owned the DD lite and the surefire m73 but the vtac is soon to be my go-to handgaurd on all my rifles.

To give you an idea of weight. My 8yr old has a hard time holding up my wifes upper with a colt ltwt barrel, w/ FSB, moe handgaurds no FH. He had no problem with a vtac 13" on an m4 profiled barrel and troy fr sight and FH

Just my .02c based on very limited experience. I'm sure there are people with more experience and knowledge than me to help you here.