Very thin mild steel you could make better with some sheet steel your self, it needs to be at least 3mm
The Steel is too thin hence the price, lite duty not heavy duty, if you set it at 50 yards and put 10 shots down it will pop the welds open so not very heavy duty at all
Such a good product and hours of fun also love the way it collect the lead pellets and its easy to tip away the pellets after you have finished. Its made from very strong material