Ammunition

Could someone briefly explain the ammo locker system to me or even point me to a thread where it is explained.

Currently I can buy standard ammo, I can also purchase other types of ammo (tracer, incendiary, etc) with mission points.

Is there any way to buy non standard ammo outside of the missions?
If I trade mission points for non standard ammo, when I have used it up can I replace it in my ammo locker using cash?

Any help gratefully received.

Special ammo can only be bought with mission points. It can't be sold, traded or bought for cash.

From the announcement when missions were introduced:

Special ammunition
Special ammunition is now available and has a chance of spawning as mission rewards. This ammunition is not intended for constant daily use, but rather for important attacks when you tactically need a power or accuracy advantage.

Hollow point - Damage is increased but armor penetration is decreased
Tracer - Accuracy is increased
Piercing - Armor penetration is increased
Incendiary - Damage is increased

Hollow point and tracer ammunition is the cheapest, followed by piercing, with incendiary being the most expensive.

To use special ammunition, you can visit your ammo locker and set the specific type as priority by clicking it. It will then be used during every attack and defend until priority is removed (by clicking it again) or all of the ammunition is used up.

Currently, and for the forseeable future, cash cannot be used to purchase special ammo. Until you have a big stockpile of special ammunition it is probably not worth using it on an every battle basis.

Not a good idea to waste points in "Hollow Point ammunation", there are armours in which your damage goes to ZERO.

Have not yet seen any enemy in which the "Tracer ammunation" have made de difference... so, still looking.

Seems the best are the Piercing and the Incendiary.