I've recently started a DH2 campaign and I do not understand the requisition system.

If a player wants to requisition a silenced autogun does he have to roll twice to requisition it? Once for the gun and once for the silencer?

Or am I supposed to combine the availability of the two items and he rolls just once?

I believe there is a system called "Combined Acquisitions" in DH 2E, though I am not certain on this. It does exist in Rogue Trader, this I know, and there it works as such.

You take the base availability of the rarest item and then add a -5 to the total modifier for every item beyond the first that is purchased alongside it.

For example an Autogun with a Silencer and Red-Dot Sight would be acquired as following:

Autogun - Average (+0)

Silencer - Plentiful (+20)

Red-Dot - Scarce (-10)

for a total modifier of Hard (-20)

I believe this was noted in the FAQ on page 11. I think this is what you are looking for:

Question: If a character acquires a weapon with modifications

already installed (page 162), how is the Availability for the

combined item determined?

Answer: The weapon is acquired as normal, then each individual

modification would require a separate Requisition test. As always,

these should be adjusted based on the location and nature from

where the attempt is being made. Alternatively, the GM could

determine that the modified weapon could be acquired in a single

test. Here, it would have a new Availability equal to at least the

hardest Availability level of the modifications and weapon, though

the GM should make a final determination on it (especially if the

Acolyte then tries to trade it in). Depending on the number and

complexity of modifications, it is possible the modified weapon’s

Availability is now Unique, for example.

~ alemander

Thanks, I guess I should go read the FAQ

Under normal circumstances, the requisition roll associated with the modification is the roll required "to go and get this mod fitted to my gun" - it assumes an existing weapon being modified.

There's a second option which improves the availability but the mod kit essentially arrives as a kit of parts - needing a trade (armourer) test to actually fit it to the weapon.

The FAQ combined acquisition is for going out to specifically acquire "a silenced autopistol" - i.e. a weapon you don't already have pre-fitted with the mod.