The way i thought of it in last post after you asked is that you could choose every weapon as a secondary weapon, so no weapon would be configured as a secondary weapon. It would be so you would "only" have the weight limit to take into consideration as in the example above. So it would all depend on where you put the max weight limit. It should be at a lvl where it would be acceptable to have:
sniper + ***submachinegun + mags + equipment
assault rifle + grenade launcher + ammo (+ equipment)
assault rifle + shotgun + ammo (+ equipment)
assault rifle + 1 shot AT weapon + ammo + equipment
assault rifle + reloadable AT/AA launch system + rifle ammo + equipment
Where (+equipment) means that a equipment thing like aone pair of NVG or on binocular would be ok but not more than that.
Where 1 shot aa weapons would be a real 1 shot weapon at not like now where you can reload and have to carry ammo for it.
Where with reloadable AT/AA weapons, which are heavier than 1 shot weapon, you would carry the lauch tube/system but you would carry the ammo in the ammo bag in the backpack menu which is how you carry it in real life.
But it shouldnt be acceptable to carry:
Machine gun + Machine gun + side arm + ammo + equipment
Machine gun + assault rifle + side arm + ammo + ammo + ammo + grenades + equipment
assault rifle + assault rifle + side arm + ammo + ammo + ammo + grenades + equipment
And so on. As said above it will all depend on finding the right max weight limit for the main equipment loadout. What you carry in the backpack doesnt matter if you would have to take it off and take thing out of it, like i surgested in the first post i talked about backpack.
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">These backpacks would increase how much you could hold but should also affect your movement and speed. Also it should be so you would have to take the ammo from the packs to your webbing before being able to use it. That way you wont be able to run around with 30 mags or something like that. So it could be something like this in the [ENTER] menu.
You would then get a pop-up inventory list of the backpack. You could then choose between the items with your mouse and mark/select the things you wish to pick up/move to your webbing or drop them to ground if you dont need them anymore.
A nice features that could be added, that also would add realism, would be the abbillity to take off the backpack, so you could leave it at a gather point before a attack.