I always found it a bit of a stretch in my suspension of disbelief in a military game, that a fully trained soldier shouldn't be able to carry his standard kit all day long while marching. Equipment weight should not phase a guardsman. Equipment bulk is a far more realistic measure for penalties in movement etc.

Well, mostly they can carry their standard kit all day long while marching.

10+ clips of ammunition is not standard kit. Actually they can carry that and a bunch of other stuff as well; they'll just gain Fatigue.

I always found it a bit of a stretch in my suspension of disbelief in a military game, that a fully trained soldier shouldn't be able to carry his standard kit all day long while marching. Equipment weight should not phase a guardsman. Equipment bulk is a far more realistic measure for penalties in movement etc.

Have you looked at what stuff weighs in this game?

They called it "weight", but bulk certainly has to be part of it, considering how silly heavy some of these things are.

Fair point. Initially the weights and carrying capacity is what made us handwaive it as is, but, we may revisit it under that PoV.

I've been very reluctant to hand waive equipment weights, especially considering my own experiences hauling my deployment equipment around (albeit just around the flight line at Al Udeid and Bagram, aircrew does have some benefits...). I've gone so far as to weigh some of my own equipment just to figure out what a guard equivalent might weigh. In addition I've given my players some credit for choosing equipment that gives them no benefit in stats or fighting but are legit things deployed soldiers would want (i.e. recaff and lho sticks being part of their standard kit), in other words the more they played a real human than an optimized dice monkey the nicer I was to them when it came down to rules grey areas and GM decision rules. Weight is the great limiting factor of infantrymen and something I personally feel should never be hand waived, there should be a great bit of agonizing over whether it's better to drag along a few more magazines/belts/charges or whatever of ammo or if it's better to bring along a ground mat to make sleeping just a bit more comfortable, and to me that's where a good GM can distinguish themselves.

Now, as to the question about ammo, that depends on what your players choose to do and how you, to a degree, push back. Granted my opinion is based off the fact that I view my players as the war movie characters with names. They may die in the last scene, but they should at least make it there. First, I enforce the jam rule of if you jam you lose all the ammo. With Lasguns this makes sense to me since the weapon can't truly jam in the sense of a weapon using solid rounds, but instead the battery is feeding all its power into the weapon and the trooper can't stop it before it hits zero charge. This happens so infrequently with lasguns it's a good rule to enforce brutally. Next, push back with weather, lighting conditions, and enemy dodges. My players are usually so high on their ballistic skill that with the normal benefits they're literally rolling to see if they jam with no penalties. Penalties are where the GM can push back, imposing darkness and rain alone usually allows me to push -30 or more on my players alone. Adding in enemies with special abilities like Step Aside or whatever the name of the one is that applies a penalty if they run (I can't be bothered to find my rule book right now) can also add some penalties to your players that will force wasted shots. The big thing to avoid is true player frustration, and I highly encourage house rules to avoid that.

For instance my highest agility players were never hitting enemies since everyone got their dodge back at the same time, and the lowest agility players were getting all the kills after the enemy dodges had been burned off so we introduced the house rule that you only got your dodge back on your turn, meaning that enemies that the high agility, high initiative players had burned the dodge off were still helpless when it came back around to their turn.

All in all I think it comes down to this is just my $.02 and you have to base what you need to do off the sort of players you have and the sort of game you want to run. Not that that's much of an answer...