Sometimes the more things change, the more they stay the same.
With all these walled compounds and impromtu urban sniper postions, the US Tactical Supply Scout Sniper Periscope Kit is a back to the future update of the Dough Boy sharpshooter's best friend.
U.S. Tactical Supply offers the Scout Sniper Periscope Kit (NSN 1240-01-571-5004). The kit is comprised of am anodized aluminum tripod mount handle with 1/4 20 threads, Desert Camo SwatScope 3M Camoclad Wrap Kit, aluminum hard case, belt hook, AN/PVS-14 Adapter, flashlight attachment, and a soft sling case. Its everything you need to put the periscope immediately into action and can be used for a variety of observation applications in addition to use by a Sniper section.
Sometimes it's not about UAVs, thermal imagers and ground bots...sometimes it's just a simple matter of refraction, defraction and a sneak peek above the roof line to zero in on the bad guys.
Maybe US tactical has an adaptor kit to attach the periscope to a M110 or M40 rifle...?