Ammo Drum and Rifle Aptitude need to go for sure. Rifle Aptitude's effect is far too little to be remotely noticeable and a Max Ammo mod isn't needed if you have a Mutation mod, especially on a slow-firing weapon.
What I'd recommend:
- Remove Ammo Drum and Rifle Aptitude. Not optional.
- Get Serration on there, even if it replaces Thunderbolt. Not optional.
- Elemental mods need to be maxed out, or they're a waste of space (as those unranked Hellfire and Cryo Rounds are). The proc chances are far too low to be considered on just about any weapon besides Grakata and Synapse, and even on those two, they're far from reliable. Get some elemental combos when fighting specific factions, and, as a general rule of thumb, have Fire on there as a separate elemental. It's great against all three factions. (Go with Magnetic for Corpus, Corrosive for Grineer, and any dual combo for Infested that doesn't require you to sacrifice Fire damage, preferably Corrosive or Viral. Even Blast, the only anti-Infested combo there is, is out of the question, because you lose fire and have to replace it with less-effective Electric or Poison.)
- Critical builds work well with bows, especially the Dread. Get Point Strike for crit rate, and Hammer Shot & Vital Sense for crit damage. The damage will be far from stable, though, so only do a crit build if you plan on doing DPS with this bow (e.g. taking out those resilient Heavies).
- Thunderbolt scales very, very badly with enemy levels and is unreliable as it is. Elementals, critical mods (if applicable), and attack speed mods should take priority. I'd replace this with Speed Trigger, or with Shred if you want to still retain some mobbing capacity.
Edited by SortaRandom, 09 December 2013 - 02:50 AM.