At first I thought the Bell New G Series CO2 Magazine for $25 was a great deal so I bought 3 of them to test out in the new Bell G17 series pistol I just recently ordered for a Customer . So far the pistol works great for him but the mags however did not. The first 2 had faulty hammer valves which I did manage to fix. the third magazine was not fixable without a new hammer valve. Airsoft Depot replaced that magazine free of charge , no problems. Now for the most concerning problem that you should know . The seal for the CO2 cartridge is too thick and the puncture needle is too blunt/short. They will not puncture a crossman CO2 cartridge after the second one is installed. the flatten out and will not work. We have also tried cybergun and daisey cartridges and none would work. 2 remedies are as follows: 1. remove original seal and use a piece of Teflon tape over each cartridge . 2.remove seal and replace with a new one which is only 1.5mm thick if you have access to material and a hole punch set. Overall impression : Great price , full trades,fast shipping, but Bell themselves need to do more homework as Myself and My customer are not impressed with the build quality of these mags. So if you do not wish to rebuild these mags then do not buy them.