Left hand 1100 3" magnum

[Virginian]

Good grief. You need to talk to some different people who know something about which they speak. They got it about backwards. No doubt from the "all powerful buckshot and slugs" school of non thought. Go to www.remington.com and download and read the owners manual. Lots of good information.
You can shoot ANY 2-3/4" or 3" load. If the barrel has a fixed choke, probably FULL, I would not shoot steel shot thru it. Steel shot is harder than lead and can damage tightly fixed choke barrels. If it is a modifed or more open choke, #2 steel should be okay. Buckshot and slugs are no more "powerful" than anything else. The maximum pressure is regulated by the SAAMI specifications for all 12 gauge 2-3/4" and 3" loads to the same level.