I remember this video , it is the periscope principle , the loss is minimal .

I did a test install with my first blinder , the head was behind the bumper , vertically oriented
shooting up to a plexiglass mirror directing the beam toward the road , though
was never tested with a real gun , just with an Osprey ...and it jammed.

I figure the Alp would do very well with a tuned set-up & the increased power compared
to the m-27 .

With the new laws coming down the tube ...we better think to stealth our installs.