Many of these probably don't have major or real differences. If we start to confirm as such, I can modify this list as a reference. Either way, it could be a good list to quickly identify variants of the same gun, plus it could identify ones that have different internals -- springs, air restrictors, etc.
Also, I kept the list narrowed down to mostly newer guns and/or ones that might be popular to modify. There are lots of variations on older guns as well, as documented by Orange's Nerf Page. I could add those in the future, but there might be a lack of utility. Also, I'm not sure Orange has every variant of every gun.
Arrowstorm
i. "version 1" old version - has dark red plastic and open holes into case
ii. "version 2" has lighter red (pink) plastic and no holes in case
Maverick
i. blue version
ii. yellow version
iii. clear Gamestop version
Magstrike
i. dart tag versions - blue and red
ii. yellow version
iii. red iron man version
Nitefinder
i. blue and silver version
ii. blue and yellow version
iii. yellow version
Big Bad Bow
i. old purple version
ii. new purple version
iii. maroon/red version
Titan
i. red unity power system version
ii. red stand alone version
iii. green Hulk version
Longshot
i. blue version
ii. yellow version
Firefly
i. blue version
ii. yellow version
Edited by NERF or nothin', 08 June 2009 - 09:31 PM.