it depends how much FPS (feet per second) your gun has. If it is at least 350+ FPS then i would go with the 8mm anything below that and the BB could break and jam your gun. But if u have a shot gun use 8mm. now this is for AIR SOFT GUNS
For BB guns, it still depends on the FPS but the BB wont break its just your accuracy wont be as well higher power should always use 8mm if its 450+ FPS
A few guns shoot 8mm pellets, but the vast majority shoot the standard 6mm pellets.
8mm
You will need 6mm plastic BB's. These can be gotten at most sporting goods stores these days. *There are also airsoft guns that shoot 8mm BB's. These are quite rare to see in the United States, so I'm betting that your gun is 6mm. .177 cal metal BB's or .22 cal metal BB's won't work in your airsoft gun.
I do not know of a production airsoft gun that shoots bbs of those dimentions but it doesnt mean its not out there As you probably know, most common is 6mm, and some airsoft guns, specifically some revolvers, shoot 8mm bb's, but I have never heard of a 7mm bb or a gun that shoots it.
7mm refers to the diameter of the bushings, which align the gears in their positions. They generally fire 6mm (approx.) projectiles. 7mm BBs are nonexistant or extremely uncommon. 8mm-bushing gearboxes also exist, though they are slighly less common. Gearboxes that fire 8mm BBs (bushing size irrelevant) exist, though are fairly uncommon.
all airsoft guns fire 6mm bb's (exept the m1 garand which for some reason fires 8mm bb's). the only thing that changes is the weight of the bbs. the lightest is .12 grams the heavyest is .45 the heavyer= slower but more accurate lighter=faster but less accurate.
It is: 0.5*6*8 = 24 square mm
you need a 8mm and a 6mm hex wrench and maybe a 10mm 13mm and 15mm sockets. First release the tension bar from the alternator and then use the 6mm hex on the inside end of the alternator and the 8mm on the other side...spin opposite directions and the alternator should come out.,
1.8cm is bigger than 8mm
6mm float is generally the size u want wouldn't go much bigger then 4 ft with 6mm if any bigger u want to start thinking about 8mm or even 10mm float and don't forget bracing
1.8 mm is smaller than 8mm. 8mm is 4.44 times 1.8.
Smaller 3cm = 30mm so 8mm is 22mm smaller than 30mm or 3cm