Very good job, sir. It looks great and it sounds great. I too have made a large and powerful air rifle. Mine was a pump and with one pump it would shoot through 5 or 6 layers of steel cat food cans. cat food cans are flat and uniform and a good gauge of how powerful a gun is. My caliber , however, was .312 which is 5/16 ths of an inch and is larger than a ,308 deer rifle. I suggest to you that you consider calibers that have the same size steel ball bearings. 1/4 inch in .24 or .25 and 5/16 in .312, 3/8 in .375 to .380 and of course 50. caliber in 1/2 inch. These will allow you to shoot ball bearings for fun at home and re-use them over and over and collect them with a magnet and save a lot of money but then be able to shoot the lead bullets with more accuracy for hunting or competition. You are young and doing so well so I know that after you make a few more of these type of guns you will have something extra ordinary to show us and make a lot of money selling them. Good Luck!
kalau material dan sistem drat n pembuatan begini berani pakai 4000psi.. big game kalau di pasaran sy enggak berani eh ngeriii ga tau bahan n teknhik pembuatannya
