I was just wondering is it possible to carry ammunition pack and tank mines at the same time? Would I have to give up the turret for one of them?
The turret slot currently holds two deployables, the turret and an ammo pack. Switch between them with your select fire key, B by default. This is in addition to the utility slot ammo pack, which will be replaced by the mines. So yes you will still have access to turret, one ammo pack, and AT mines all at the same time. Things to note: the turret slot ammo pack is currently bugged to function as a level 3 ammo pack regardless of your ammo pack cert level. If you upgrade your utility ammo pack (why do that when you have mines?) to level 3 you will only be able to place one at a time, but at any other level you can place both. The turret ammo pack is confirmed as a feature, the always-level-3 aspect is confirmed as a bug.
When you have the ACE out (the turret disc thing) press B, it then turns into an ammo pack you can deploy. You can press B again to turn it into a turret. You always have ammo packs on an engineer.
