I own all these types of weapons! although I wish I get to play with the SAR21 !
http://i3.photobucket.com/albums/y66/davechng/Guns/guns.jpghttp://i3.photobucket.com/albums/y66/davechng/Guns/IMG_0472.jpgHere is my opinion to the bullpup!
Bullpup has its advantage over conevntional but also has its down side.
1) Advantage being it is very well balance compared to the conventional which usually have a muzzle heaviness becasue of the heavier barrel ( on HK G3, FAL, M16A2 type weapon) the bullpup having the barrel push back actually makes it balance much better.
2) Bullpup can have much longer barrel, My AUG having 20" barrel is shorter than my 14.5" M4 or the AK74. thus for little bullet like the 5.56 that requires hi velocity for the 5.56 to do its wonder, the barrel length will help significantly.
3) Ergonomics, some people like it but I do not ! the mag release is in a awkward position! but again a toss since some people argue they like it!
Disadvantage,
1) not able to switch left to right..The AUG do have an left hand bolt ! but do not know if the SAR21 is capable of switching!.FAMAS can be swithc over to lefthadn also! and during tactical movement your strong sweep is easier but the weak sweep side you have to shift your body position much more.
2) basic ergo I feel the M16 series weapon is much easier to handle faster!
3) trigger is much more difficult to be as crisp ! due to the design of the bullpup , the trigger bar is far forward and needs and actuating rod to the disconnector ! thus in pure physics its harder to tune a good trigger ( but again we are not talking about sniper or precision rifle so this factor is usually overlook)!
As for the MP-5 over the M16, well! mag release is of the latch AK type ! the button release ( unless you have very looong finger) you can never reach it ! not even my Special forces freinds here in the US can reach it... the cocking lever is awkward, you have to reach out to get to the cocking handle ! MP5 is easy! but the G3 or the HK33 is very difficult ! and the MP5 do not hold the bolt open on last round( unless you get the newer MP-5 40 or 10 which has the bolt release add on)! to load a fully loaded mp5 mags !it is usually easier to load it with the cocking handle open! this goes with teh G3 and HK33. ! ergonomically the HK system really is BAD compared to the M16! in all ways! Howevr it does have a better sights than the M16 ! but than when we are using Aimpoint, EOtech or ACOG ! who cares about the iron sights!
The M16 family still have its place But I wish someone will come out with a good , perfect piston system and we can all live happily ever after!
DAveC!