The G36 Comes in several variants:
-G36: Standard version
-G36C (Compact): Small SMG version capable of heavy external modification
-G36K (Karbine): Shorter version of the G36
-G36E (Elongated): Longest Version of G36
-MG36: Light Support Weapon featuring a bipod but based off of the G36 or G36E model.
The G36 also has several magazine lengths:
100 round "Beta C Magazine"
30 round Stick magazine (available in black or clear versions)
10 round sniper magazine
Ive fired the G36 both real and airsoft and both are extremely effective and responsive to the pull of the trigger.