That I agree with whole heartedly, I do not think making all ammo tt is a good idea. From my first post - "I love the idea of the crafted ammo" .
This is why I suggested making 'some' crafted guns (better than level 20) use a tt ammo and leaving most to use the crafted ammo they use now. Then at least we could hunt more than beginner mobs from tt ammo and leave the crafted ammo for the biggest guns and some looted ones. I also believe that would give crafters something more to sell with some mu on it.
But again I'm sure there are other ways to solve the lack of ammo, this is just one possible solution and possibly not the best.
Increasing the supply of ore's would also help, I'm just not sure how that could be done without increasing the cost of bombs and gear which may cause even less people to want to mine, at least people just starting out in the game.
Maybe use less different ore's for ammo? (currently it takes 7 ore's, some of which are already in high demand for other crafted items) I don't know.
Rumor has it that the terrain will get some updates soon, this will (for me) also help make mining more fun I hope