Multiple One Shot Weapons

OK, I can`t seem to find it in th RB.
A Razorwing Jetfighter has 4 missiles (One Shot) - when do I declare how many am I using in the shooting phase? Do I declare before shooting or after each shot?

Like all vehicles you have to declare the targets for all weapons firing prior to rolling any dice.

So no seeing how many you kill before firing a second missile...

Actually you even have to declare who will fire at whom before meassuring range, and of course you can't change it afterwards.

BRB p.16 wrote:

A player may choose not to fire with certain models if
he prefers (as some models may have one-shot
weapons, for example). This must be declared before
checking range, as all of the models in the unit fire at
the same time.

BRB p.58 wrote:

...exactly as if each firing weapon on the vehicle was a
separate firing model in a normal unit.

So its like "I use 2 missiles on that unit" and then I can only use 2 missiles, right?

Thx for the quick reply

Yes, normal process would be to declare: "I'll fire the Dissies, splinter cannon and 2 missles at this Termies." and then you meassure the distance and resolve the hits. If you happened to be in like 38" range you'd of course discard the splinter cannon and the dissies and so on, but after declaring what shoots, you can't change it anymore.

I don`t miss on ranges, so that won`t be a problem

Do these separate missiles counts as separate weapons regarding weapon destroyed result?

Yes, they do, but once fired they can't be destroyed anymore.