Inspired by real world load bearing equipment (specifically MOLLE system) I use home made rules which limit the marine carrying capacity not based on weight alone, but also by the volume a power armor can fit on it... Which is far less than the actual weight a marine can carry.

For this purpose I've made a Marine Carrying Diagram

Please do note that the Diagram works with the basic assumption that every marine backpack is fitted with 6 magazine pouches which each can carry one boltgun or bolt pistol magazine. These 6 magazines plus the ones inside his boltgun and boltpistol is "standard loadout". These pouches are fitted so that its easy and fast to reach behind your back for these magazines.

Everything above that must be attached to one of the six 'carrypoints' which are basically multi-functional attachment points in the armor that can fit different types of pouches, bags and other stuff. Unlike in modern world load bearing equipment I've never seen (in art or in models) marines using the chest area for carrying equipment so I work with the basic assumption that it is somehow impossible and limited that out. If you feel you need a 'reason' for it lets just say that the power armor limits your arm movement in such ways that its not viable. Thus there are four attachment points in the waistline/thighs and two in legs, but none in arms or chest.

The basic idea is that you can fit each attachment point (carrypoint) with one (two in case of grenades) item that is avalaible fast (can be used with Quick Draw and Rapid Reload) or a bag which will carry a lot more with the price that you actually have to open the bag to reach inside (which prevents using Quick Draw or Rapid Reload).

Feel free to abuse the idea

Great job !

As for the chest, though, it would be the perfect place to block your mag-lock'd boltgun when not firing

Nice

A thought what about lose rounds boxed, not in mags but lose for refilling mags, how many would be fair?

This would also allow assault marines to carry some rounds for the squad heavy bolter.

This picture is from one of the Imperial Armour books and is in my mind one of the very best showing where marines can have ammo

creativetwilight.com/2011/03/into-the-power-armored-blue-yonder-i-break-a-long-standing-vow/

I know in real life, soldiers don't go out on missions with just lose rounds. Their basic load is 7 filled magazines. Any additional ammo would either already be in magazines, or be in the metal ammo box that it comes in to save space. i'm not sure what the capacity of ammo box of bolter rounds is, but something like 5-7 magazines worth would probably be fair.

It really depends on the kind of mission you are going on what amount of ammunition you will have.

'walking around rounds' was on you body at all times, which was two magazines

'short patrol' meaning you will be gone less than a day means carrying as many rounds as you can and skimping on food and water a bit.
I remember having one in my weapon, one on my weapon, six on my vest, and four more on my left left. This is in addition to an assault pack with a box of rounds for the saw and two grenades if we could get them plus a knife

'vehicle mounted' means you have the above minus the pack, which is actually just slung next to your seat in case you have to go walking out of sight of your vehicle.

'long range patrols' meant that you would be spending several days or more away from resupply. You have a long range pack and a field pack and the assault pack. The long range pack has 1-2 weeks of food, clothes, medical supplies, ammo for the squad weapon, and boxed rounds, which came on stripper clips (not as interesting as it sounds) which could be used to quickly reload magazines.(it takes less than thirty second to reload a magazine) In most combats you will never go through your full combat supply, the rounds in your pack can be used to reload your magazines between battles.

For a space marine dropping onto an unknown world where he may spend several days to months fighting constant battle, you are going to need more than 7 magazines. This is especially true for deathwatch who are such a small group that they have to expend a much greater volume of ammunition in order to beat their enemies.

Using the MOLLE system is a great idea; however, there are many versions of the molle system. Here are a few examples:

1) Rifleman's set- basic molle system all infantry soldiers are issued, and comes with 3 3-mag pouches, 2 grenade pouches, 1 flashbang pouch, 1 3-mag pouch, a waist pack, and space available for optional pouches.

2) Grenadier set- a set of pouches to allow for M203 grenade launcher (a grenade launcher attached under the barrel of the M4 or M16A1/2 rifle) rounds. 10 single HE (high explosive) rounds pouches, 4 double HE round pouches, 4 double pyrotechnic round pouches. The grenadier set is a set of pouches that are used to be placed on the standard rifleman's set for the M203 grenade-launcher gunner.

3) Saw gunner set- a set of pouches to allow for additional M249B (5.56mm machine gun) rounds. 2 100-round pouches and 2 200-round pouches. These are used to issue to M249B saw gunners to allow for 600 additional rounds of belt fed ammo, and can be placed on the standard rifleman's MOLLE set.

4) Pistolmans set- to allow for additional M9 (9mm pistol) magazines. 1 tactical drop leg extender and 4 single magazine pockets.

5) Medic set- 4 zippered medical pouches, 1 medic pack (as the name suggests, this pack is much larger than the medical pouches) w/4 quick release medical pouches.

As you can see, with the first set and sets 2-5, you can carry much more than you would think. And this is made for a soldier not a Space Marine. Between the bulk, muscle make up, and extensive training, a space marine would be able to carry twice this amount of weight. You could easily say that the MOLLE system for a space marine would be twice the size of what it is. It wouldn't be hard for a space marine to have webbing (which is expressed in RoB) to carry a solid combat load.

Here's an example space marine MOLLE set-up for my Ultramarines Assault Marine/Chaplain;

quick-release leg holster (right leg) for bolt pistol, quick-release leg holster (left leg) for plasma pistol, custom combat-sling for bolter (it has a snug fit around the shoulder and a custom slider for quick bolter raises from the ready position, and allows for a snug lowered position when not using the bolter), 4 bolt pistol magazines (all fit on the holster), 8 plasma pistol magazines (4 fit on the holster and the other 4 are on the combat webbing on my torso, 6 bolter magazines (fitted into 6 pouches w/3 near my left hip and 3 near my right hip, 2 frag grenades (located on utility belt), 2 krak grenades (located on utility belt), repair cement that sits in a pouch on my utility belt, the combat knife sits in a custom made sheath on my left leg, and a custom made chain sword sheath for my right leg. I walk around with my crozius arcanum and plasma pistol.

Here's one better, check out this link to get ideas for space marine combat-webbing

http://www.armyproperty.com/Resources/NSN-Listings/MOLLE.htm

Just remember that when playing a space marine you're playing a space marine, and you need to keep things like challenge, balance, and fun in mind when scoping things out. It all depends on what you're going for.

If getting a precise count that means that your team will likely never have to track ammo, then go for it.

If ignoring ammo all together is your cup of tea, go for it.

If you want your Kill Team to think about conservation of ammo, I'd suggest using the alternate rules in the erratta and go with 6-9 clips for your main weapons (depending on how you read rule of three and the fire selectors). This is not 'realistic' compared to what modern humans go through in actual combat, but it fits for the game, I've found. If you give your Heavy Bolter operator 600 rounds of ammunition you may as well not bother tracking it at all- I don't know about your games but a short skirmish of 5 combat rounds can take an extended period of time to play out, let alone the 100 or so you'd get with that much ammo. Most of my missions don't last through 100 or more rounds of combat.

As for Polaria's chart- I think it's pretty good, and stops the dual wielding heavy bolter fighters in their tracks cleanly, and presents what appears to be a pretty reasonable loadout for most rpg missions.

Thanks for the ideas, my group has been debating the amounts that we can resonably carry and this should help a lot. We prefer to track ammo as we dislike the rambo-gun infinite ammo option.

How do you guys handle stowing Heavy Weapons? In our campaing we've had several instances where we've needed to climb up/down a cliff or buildings/walls and handle barricades.

We just decided that there were 2 special mag-locks on the ammo feed/power cable side of the Devastator's backpack that would lock in the marine's heavy weapon. Since it could be a flip the weapon / swing it back, we've been doing no-test for a full action or 1/2 action w/ agi test to stow a weapon and 1/2 action to ready again.

Probably not very realistic due to the physical size of most of the heavy weapons, but it does let our Devastator climb/rappel and do other manual tasks as well as fighting in melees etc.