Its an old topic but i hope someone gets notice of it and spreads the news to all 410 users. My slug load data tested and confirmed regarding their safety from a proffesional reloader (a friend). 10mm FMJ 180 grain Semi Wad Cutter slug/ Fiocchi 410/76 plastic hull/ Fiocchi 615 primer/ Vectan SP3 Powder 18 grains/ slug wad. About 940fpe muzzle velocity. 5 Shots 2 MOA at 215 yards with a fixed (non magnified) Red Dot from a bench rest position. & 10mm Lead Semi Wad Cutter Slugs 175 grain cast from a lee 410 - 175 mold. Same components except powder. Powder with this one allows for 20.6 grains. & 4 Buckshot pellets of 8.6mm diameter 237.7 grain all together with a 40mm wad container same components except powder. Powder load is 15.5 grains. It performs around 1400fps. (Not muzzle velocity but actuall velocity of the 4 Buckshot pellets. Why not 5? Because their velocity will drop quickly. & Another load would be the same formentioned with a CCI large pistol primer and brass cases but haven't tried it yet to devellop any data. Sure thing is the Magnum pistol primers combined with slow burning powder and long barrels work wonders! I haven't confirmed the ballistic calculation tests by my self to give any details regarding fps and fps drop regarding distance etc. Will do this year though. But i shot it and it works well around 100+ yards and good enough at 150+ yards. You will reach 200+ yards if you know what you re doing but don't expect an ''effective range'' above it. The 200 yards shots haven't been tested regarding penetration of skin and clothing so i don't know if they are reliable.