Carbine V Bullpup

[StainlessSteelCynic]

I think that what's being illustrated here is the need for training on any new weapon you may get. For example, the first military rifle I trained on was the L1A1, the second was the M16A1 and finally the F88 Austeyr (Australian AUG). All three have different magazine releases and while I found the M16 has few competitors for a fast mag release, I was just as fast on the F88 as I was on the L1A1 despite the F88 being a bullpup.
I'd hazard a guess and say that people who have trained on the M16 family would probably find many other rifles to be slower when releasing the magazine simply because the M16 family have a very positive, gravity assisted magazine drop action when most of the others require you to activate the release and manipulate the mag in some manner.