My understanding is that the L85 (and the FN-FNC and possibly the Steyr AUG) all were designed to accept the M-16 magazine, which is available in sizes from 5 rounds up to 100, although the 20 and 30 are standard in US military issue, the 20 much more rarely.
As for the MP-5, I think it has something to do with the sophistication of the action - its an elegant roller system as opposed to a simple blow-back system. What the practical effect is I can't say, but if game stats are based on things like barrel length and rate of fire I can see how it doesn't stand out from the crowd.
I'll wait for some of the real heavy-duty gun guys to opine more...
|