mid length gas system

[Rwatts62081]

Will a Daniel Defense Mk18 RISII rail fit behind a standard FSB in the midlength position? With as small a gap between them as possible?

[Col_Crocs]

Short answer is no. If you have a low-pro gb, the RIS II MK18 will cover about a third of your gb. In turn, some LP GB's will require some "dremelling" on the bottom to clear the chin.

[Todd.K]

You need a 9" rail to fit behind the FSB on a mid length.

The Mk18 rail is more like 9.5" long.

[LONGBOWAH]

Another way of looking at it is that the length difference in a carbine versus midlength gas system is 1".

Unless your FSB (which as stated is more like 1.5") is 1" or less, the answer is no.

[Rwatts62081]

Thanks for the answers guys. Not what I wanted to hear, but at least I know.

[Failure2Stop]

The DD RISII is a good rail, but there are other options out there that are just as good, and even better, for about the same price.
Don't be too heart-broken.