Just got back from the range. I was running just Sellier & Bellot Special Sport Slugs (2 5/8 with 1 oz load).
Mags were all fixed by Wolverine and I disassembled them all, cleaned and lubed them.
Shotgun had barrel & chamber cleaned, lubed. No disassembly yet. Lots of lube could be seen though.
Shot about 75 to 100 slugs.
Had about 20% where the cartridge jammed up at 45 degrees on its way to the barrel.
Occasionally there was a failure to feed from the mag, by jogging the charging handle down a bit, the round would be picked up and fed.
Sometimes an entire mag fired every shot without any issue so I'm guessing it's not the ammo at fault here.
BTW, I also tested out a red dot, a Browning Buckmark Reflex sight (cheap but kept on working). So you don't need a $500 red dot on this gun.
Overall really pleased with the shotgun! No one really told me how much fun it is to shot!

Lots of people at the range came to have a look at the odd shotgun.
Thanks John for bringing these in for us.