yes you can put a 2 3/4 barrel on your mag receiver
not sure how light you are talking about,,,but any standard velocity 2 3/4 load should make it cycle
for the clays you will just have to get a box that you plan to use and give it a try
my mag 1100 with a 2 3/4 barrel functions fine with Winchester AA,,, yours may not,,,just need to try what ever shells yo plan to use,,if they don't cycle try a different shell,,maybe a little hotter
my .02
ocharry