SGL question

I’m planning on potentially going with a friend to the SGL in Wexford. I have an M1 Garand and a handgun and I’ve only ever shot indoors. Would the 6 round capacity mean I can only load 6 rounds in an enbloc/handgun mag at a time?

Also, what would I need to bring? I’m looking at bringing eye pro, ear pro, targets, and a stapler w/ staples. Do I need anything else like a benchrest?

Thank you!