I want to replace the Diamondhead hand guard on my stag piston upper. I just came across the Fortis mid length cut out rail and had a few questions google searches haven't been able to answer. Here's the gas block on my stag piston . The hand gaurd currently on my stag is 11 inches in length

The fortis carbine length  cut out rail obviously would fall short given that it's 9inches. However, I'm reading the fortis mid length cut out rail is 14 inches. Is that correct? Or is it 12 inches?
Mid length cut out

I simply want a FF rail with a cut out for my piston gas block. But I'm not sure what length will be compatible. If you guys have any input on this matter or know of a better substitute for this 11 inch diamondhead handgaurd it would be greatly appreciated.

The 12 inches or the length at the top
The 14 inches is the length of the bottom

I've heard that geissele makes a FF rail that is compatible with piston gas blocks. I can't find a concrete yes or no to this you wouldn't by any chance know would you?

I know nothing of Pistons.  There are so many configurations and incompatible parts that I don't understand why anybody chooses the piston over DI.

Modularity and compatibility are nice

Topic Moved

Please someone help me on this issue.

Just measured my Fortis midcut rev.

Top rail: 9 1/4
Bottom and sides: 11 3/8

Width of cutout:  1.18

If you need more measurement, send me a pm and I will post them here.