A problem that has plagued the ARMA series for a while is the lack of a proxy to have different magazines display in real time on weaponry, meaning if you took the 100rnd 6.5 Magazine for the MX-SW and put it in a regular MX the magazine would still look like a 30rnd (even though I recall a version in the Alpha having this ability).
Its particularly disappointing when mod developers have plans for different types of magazines like drum mags, yet they will not look any different. I wouldn't have thought such a feature would be too hard to incorporate and mod developers could use it to great effect.