I bought a couple of bags of these things and used them with a Cyber Gun CO2 Desert Eagle 50AE semi/auto. This was the UK variant which has a label reading over 1 joule yet main box claims 0.9 joules (396 fps with a .12bb). The gun has a spin up feature meaning it will put back spin on a bb fired for more range. These BB's fit standard 6mm airsoft guns but they are made slightly smaller, which should increase performance in theory. I noticed that these bb's being this size and being .25 in weight required me to increase my spin up on a high setting to clip the bb more, I was shocked at this as my gun in review claims to have a heavy spin effect and at default settings will make a .20 bb shoot slightly high. The BB's are very pale green colour almost white and are very smooth and well formed in shape. Using my loader I have gone through about 600 to 700 rounds without a single jam I assume this is good as many have told me co2 guns can jam. Going by these BB's they don't! on a full co2 capsule these bb's were tearing through tin cans, shooting through plastic paint containers filled with water and cracking a smaller container inside the first. I was then testing these for shooting at a person. I tested them at around 10 yards then 20 yards. I would assume the BB's where know traveling around 300 feet per second. The person being fired at was wearing 2 heavy hooded jackets over a jumper and two tshirts. The hits were felt and described as a mild bee sting that goes away quickly. I gave these BB's 5 stars because they just seem to be perfect for everything and group really well out of my gun. I would say you need to be using these with powerful airsoft guns of at least 0.8 Joules.