Well, I have been going through all the cobra ranks trying to figure out what figures fit, what figures don't, and what to do with those that do. Most of my collection will be RAH, with the exception of B.A.T.s which don't need to fit the standard buck. So what to do with all those B.A.T. variations? Well this is what I have done. (images courtesy of yojoe.com)
1st GenerationBAT 1.0- This is the first generation BAT. It first saw field operation in 1986, and was used until its replacement, BAT 2.1, became operational in 2003.
2nd GenerationPrototyping on the second generation BATs started in 1991, however the production (version BAT 2.1) did not see the battlefield until 2003.
3rd GenerationIn 2002, prototyping began on BAT 3.0. It was to be the first BAT without hand attachments. This was scratched in favor of attachments on version 3.0.1
The first production version was BAT 3.1
The BAT 3.2 integrated firmware upgrades that fix IFF module malfunctions. Version 3.2.1 was an experimental version using gold wiring upgrades, but proved to be too expensive to continue. Version 3.2.2 contains all the upgrades of 3.1.1, but without the gold wiring
The final 3rd generation BAT is version 3.3. It's firmware has been upgraded to function properly with the newly created BAT 4.2
4th Generation2004 marked the beginning of the fourth generation. Version 4 features dual interchangeable limbs for the first time. The fourth generation went through two prototypes, 4.0 and 4.1, before the 4.2 became operational.
5th Generation2005 marked the beginning of the fifth generation. These (B.A.T. 2005, v16) are commonly referred to as Sky B.A.T.s due to their propulsion backpacks.
I left BAAT v1, Inferno BAT v1, and BATs v10 & 11 off the list. I figured v10 & 11 could also be Inferno BATs due to their colors.