Does anyone actually know what kind of weapon, "rifles of considerable weight" these rifle teams were using?
http://www.lrml.org/historical/metford/2000yards.htm[/quote]
I have no idea unless they were bench guns. There may have been a few Confederate sharpshooters using them, but all of the examples I've seen or read of being used by them were either Whitworth, Kerr rifles or Enfield or Springfield rifle-muskets that were scope or sighting tube mounted.
When two-man teams went out, one of them was basically a spotter, much like teams today.
Northern sharpshooters did use heavy barreled bench guns on occasion. These can weigh up to 50 pounds, (looked at one yesterday that would easily go that heavy), but probably averaged between 20 and 30 pounds.