I spent a lot of time to unlock the catalyst for tommys matchbook and I don't know if it's even working. I don't even know what it's supposed to do. The description says, while ignition trigger is active, you recover health faster. Well, ignition trigger constantly damages you, so you obviously don't recover health at all. Rifts don't heal you faster, which would be unfair to titans and hunters. So it would make sense if you recover health faster after you burnt yourself, but I timed it before and after unlocking the catalyst and I didn't saw any real difference. Does anybody know if this catalyst is working at all? I actually like the gun but this is just disappointing.
If I recall, the faster health regen occurs when your health goes below 1/3 (since Tommy's takes 2/3s of your health to begin with). I think that's so you can continue to fire it while receiving minor incoming damage.