You can specify a Battle Royale loadout which consists of five weapons (with attachments) that will be available to you in an airdrop. These will come with full ammo. The first airdrop happens after awhile into the match and comes as a crate that everyone will share, usually causing some skirmishes near it. This means that you will only end up with your custom weapons if it is convenient. Ambushing enemies at the first airdrop is also a useful tactic. Get your custom loadout by clicking on ARSENAL when at an airdrop crate