What type of gearbox does my gun have?

For those who want to know what kind of gearbox they have in their gun.

V1 Gearbox
FAMAS F1, F2


V2 Gearbox
AR-15 Variants, MK5 variants, MK23, G3, MK16/17, ACR/Masada (the A&K is a V2, the PTS is a modified V2), JLS F2000 (modified V2)


V3 Gearbox
AK Variants, G36 variants, Sig551/552, UMG, AUG, MP5K, Galil

The SIG family of replicas DO NOT use a NORMAL version 3 gearbox. They accept version 3 parts, but are different in many ways. They look similar, but the SIG gearbox, like the version 2 gearbox uses the heat sink in the pistol grip to support the motor and does not have a motor cage. Furthermor, the SIG gearbox has a very unique fire selector.

V4 Gearbox
PSG-1, Guarder TK65


V5 Gearbox
Uzi (Tokyo Marui only)


V6 Gearbox
P90, Thompson, TAR21 (modified V6), G&G F2000 (modified V6)


V7 Gearbox
M14 variants


Note, there are many different specs of the V7 gearbox than there are any other. In fact, not a single brand has exactly the same specs as any other. This makes upgrading it a bit complicated, be sure to research for the correct parts. Also, Arnies Airsoft incorrectly states that the V7 is the ICS split gearbox type. It is not.

V8 Gearbox
Type 89 (Tokyo Marui only), like a V2, but it is unique in that it has a mechanical burst setting



V9 Gearbox
Tokyo Marui Recoil Shock Series AR Variants, MK16, and G36K


It is commonly mistaken as a "modified V2" gearbox, and even Marui markets it as one, bit it does not use any V2 gears, pistons, spring guide or other internal parts. These guns are also unique in the fact that they have a function bolt catch, recoil system, and a mechanical blowback system that does not significantly weaken the gearbox.

Split Gearbox type
Echo1 XCR, ICS AR-15 varients, ICS MX5 series, Systema PTW. The V4 is also split, bit falls into its own category.



These are unique in the fact they are two pieced. Both ICS series are the same gearbox (shell at least). The ICS split gearbox also has a functioning forward assist that releases the ARL to decompress the spring. The XCR is a bit more like a split V3, but takes mostly V2 parts nonetheless. The Systema PTW gearbox is also split, and entirely proprietary. Also, note the PGC Pro-Win V2 shell, a CNC'd aluminum V2 that is split, and fits in any AR-15 variant that uses a standard V2 gearbox.

As a note, while some gun's gearboxes fall into the category of a given gearbox type, not all brands follow the original TM specs. KWA, Classic Army, and Ares for instance. Do some extra research regarding your gun's specific gearbox before buying parts to ensure they will all fit.



References
http://www.arniesairsoft.co.uk/?filnavn=/articles/21c/gearboxes.htm
http://www.acmeairsoft.com/showthread.php?t=5820
http://www.tokyo-marui.co.jp/products/01/sopmod_m4/index.html
And airsoft retailers that mention the type of gearbox that a certain gun has.

Tweaked a bit.

Some splits GB's like the ICS can take most version two parts, including electrical stuff. The XCR, is kinda funky in that manner. It can use standard version 2 contacts with a slight bit of modification, but pretty much everything else(selector plate, cutoff lever, trigger) is different. Just thought I'd toss that out there.