I've started a process of calculating ammo weights for the guns in Dark Heresy with one of my players, to replace the current system of 10% weapon weight as it creates contradictions like identical shotgun shells weighing wildly different amounts. For the magazines we are using 40% of the weight of the ammo that they are meant to hold as apparently that is a fairly good approximation of the weight of magazines. The magazine weights have been rounded in many cases to make calculation of overall weight easier.
The long-term goal is to have an ammo weight for every gun up on the main site of Dark Reign so that it’s a simple case of looking it up but I think giving my reasoning for the weights allows for constructive criticism. All of this is subject to change.
When using these weights the magazine is considered to by full until emptied, weight is considered constant during a combat encounter. GM’s should feel free to allow players to consolidate ammo as makes sense.
With all the different guns available for the SP class it can be tricky. For SP weapons the weights have been modelled off of real life rounds that we feel match the effect of the weapons they are meant to represent. No doubt people will disagree with my choices but bear in mind that the rounds have been chosen for their weight so complete accuracy is not required.
The standard autogun round should be used for any weapon that has 1d10+3 damage. For the standard autogun round we chose the 6.8mm SPC round as it is considered an intermediate round, I felt that the 5.56mm NATO round would represent an autogun with 1d10+2 damage and bigger rounds were either too heavy or too inaccurate.
This gave the autogun ammo the following characteristics.
Full Mag - 0.85kg
Magazine - 0.25kg
Single Round - 0.02kg
30 Rounds - 0.6kg
This is over double the weight of the autogun ammo given in Dark Heresy and in my opinion better represents the challenge of carrying ammo. It should also serve to give another balancing factor in favour of las weapons.
For the 15 round Armageddon pattern the 7.62mm NATO round was used to calculate weight as it is a heavy but powerful cartridge.
Full Mag - 0.5kg
Magazine - 0.125kg
Single Round - 0.025kg
15 Rounds - 0.375kg
This actually leads to reduction of weight for the standard Armageddon clip due to the fact that the Armageddon only has a 15 round clip and the gun itself weighs 8.5kg leading to absurdly heavy ammo for the Armageddon under the standard rules, over double the weight of standard autogun ammo for half the rounds.
SP pistols doing 1d10+3 damage were assumed to used the 9x19mm Parabellum. In the world of standardisation that the Imperium is so fond of we assumed that all pistols of the same damage were designed to use the same rounds.
Single Round - 0.013kg
9 Round Stub Auto Magazine - 0.043kg
9 Rounds - 0.117
9 Rounds in magazine - 0.16kg
6 Rounds - 0.078
The change here isn't much but the goal is more to create parity between the other weapons that use the same ammo like the Phobos which is itself lighter but whose ammo should be the same weight.
SP pistols doing 1d10+4 damage were assumed to use .45 ACP ammo. Weights to come.
For a lasgun we decided that 0.5kg was a fair weight for charge pack and laspistol 0.35kg. Since we had little real world evidence to base them on we went for something that would make sense for the background of 40k, we figured that the lasgun was a popular choice because for a lighter weight you got more shots. In the case of the pistol the charge pack is scaled down but they wouldn’t be too much smaller as they still need to generate enough power.
Since the lasing cavity will be more important than the power pack and the background states that power packs are interchangeable then only one weight is needed for the entire basic las and pistol las range.
Ok here is where things get controversial Bolt ammunition. Being very rough we came to a figure for Bolt ammo that we felt comfortable with, that said it is very heavy. In fact it’s so heavy you realise why a normal boltgun does not have a full auto setting.
Single Bolt – 0.125kg
24 Bolt rounds – 3kg
Boltgun Magazine – 1.2kg
Full Magazine – 4.2kg
8 Bolt Rounds – 1kg
8 Round Bolt pistol magazine – 0.4kg
8 Round full mag – 1.4kg
6 Bolt Rounds – 0.75kg
6 Round Bolt pistol magazine – 0.25kg
6 Round full mag – 1kg
Since I am guessing that a lot of people will not like these weights I suggest that if that is the case to half all of these weights. Personally I like the fact that bolt ammo weighs a tonne.
Plasma flasks were tricky as there is little to compare them to. In the end I used the weight of a small hydrogen container. The weights in the brackets are the empty weights.
Primary Flask - 0.75kg (0.12kg)
Secondary Flask - 0.6kg (0.09kg)
Both - 1.35kg (0.21kg)
Primary Flask - 1.0kg (0.16kg)
Secondary Flask - 0.75kg (0.12kg)
Both - 1.75kg (0.28kg)