On Green / Top gas, it is spitting out 8mm 0.35g BBs at about 330 fps which means about 1.8 joules of energy. Thats about the same as a 6mm 0.2g pellet doing 440 fps. The hop-up is adjustable with a tool on the top-side. With high grade Marushin ammunition, correctly tuned hop-up and the right conditions this weapon can knock shots out to about 50m or 160 feet in stock form. It can potentially outshoot and outpower ANY airsoft gun in the market. I upgraded by switching the chamber out to a CO2 instead of the green gas. The distance is suppose to double plus, but I have not gotten the chance to check the full distance yet. I do love the fact the each bullet casing inserts one 8mm shot chambered, so it truly is one shot one kill style, and the casing does eject out just like the authentic sniper rifle along with the authentic 31lb weight.