You'll receive this one as a reward in the quest

Avas Attractor - If are less than level 50 in your Ranged skill , you'll receive this one as a reward in Buy RuneScape Gold the quest. This piece of equipment takes up 60% from your ammo. About 20% breaks (which is the norm for all types of ammunition) and the remaining 20 percent is left on the floor. It also adds a bonus of 2 to your accuracy range.

Avas Accumulator - Once you reach Level 50, if your already own an Attractor, you are able to visit Ava then upgrade your Attractor offering an arrow made of steel with 75 points as well as 1000 gold. 

If you've finished this quest before hitting 50 Ranged, you'll be able to get this upgrade right away, without other payments. This better version will increase pickup rate of your ammunition from 60 percent to 72 percent. The upgraded backpack comes with added +4 Magic Defence and +4 bonus to your Ranged Accuracy score.

Avas Assembler - And last but not last but not least, we've an upgrade that requires the completion of Dragon Slayer 2 quest. With the help of Vorkaths head and 75 Mithril Arrows you can upgrade your backpack once time. Although the best version have very high requirements, it's definitely worth the investment.

You won't drop any ammunition on the floor because this takes it all. 20% of it may continue to Buy OSRS Fire Cape break but it's always an improvement. It is also the best in the slot item for this Ranged cape slot as it provides +2 Ranged Strength +8 Ranged Accuracy, and +1 to every Defence stat except Magic which gives +8.