Over 1000 hours playing the game (mostly MP. (still seems like the best research out there on it) While this is a super late post, and literally my first post on the forums. finishing off now with Reserve packs to get the Ultra Rare weapons. Due to its spread, its most effective near point blank range. I ended up buying Reserve packs (got a few until I got all the classes I wanted, Recruit Packs til I got all that to rating X (10), then Veteran Packs until rating X (10), then Arsenal til I got all rare weapons to X (10). The highest DPS gun in the game is currently the N7 Piranha shotgun. So your odds of getting a Ultra Rare weapons are always highest from Reserve packs. Typically, with this level of variety, there are going to be a number of hits and misses, and Mass Effect 3 is no exception to that generality. By the end of the game, you will likely have an entire arsenal of shotguns, pistols, SMGs, assault rifles, and snipers to choose from. But once those are maxed you're much more likely yo get rating IV (4) equipment, it does not increase the odds of getting Ultra Rare weapons. B ioware outdid themselves when it comes to the weapons available for Shepard and the crew of the Normandy in Mass Effect 3. You're almost guaranteed to get 2 weapons from an arsenal pack as long as you have rare weapons to unlock.
Sounds a little counter intuitive to buy recruit packs to get weapons.
