I'm sorry if this has been discussed hundreds of times but it's my first time playing. I'm at the final boss fights with Leon and half of my weapons (the good ones!) seem to be disabled. I can use the pistols and shotgun but the better ones like the rifle, magnum, etc. are greyed out. Am I doing something wrong? Is this normal?
I don't think ammo is the issue. When I break crates there is tons of ammo for these weapons lying around but it doesn't let me pick it up and use it. Are you saying you don't have the same behavior?
Your inventory is full. Whenever there are no enemies, press Y and manage your inventory. It appears that you can't have everything, so you might need to throw away ammunition or grenades you don't normally use in favor of the ones that you will use more often. You can also make space by mixing your Herbs together and then add it into your pill case to make more space for ammo.
My thoughts about Bioshock Infinite: http://tinyurl.com/mn5ll4x (WARNING: CONTAINS SPOILERS)