Before I submit this as a bug, I’d like to hear how weapon rarities are supposed to work. I couldn’t find any reliable pattern as to how they are applied. From what I can tell there are packets of +15 % Damage / +10 % Fire Rate / +10 % Critical Chance as well as bonuses to Knockback and Elemental Power that can be applied one or more multiple times. But there seems to be no rule how many packets per rarity a weapon can get. For example, I’ve seen a Common Sniper Beam with +15 % Damage, an Uncommon one with +30 % Damage, and a Rare one with +15 % Damage and no other bonuses. Or an Uncommon Arlabastard with +15 % Damage (one packet), another with +20 % Fire Rate (two packets), and a third with +15 % Damage & +10 % Fire Rate (two packets). Or an Uncommon Sparkler with no bonus whatsoever. See a full list of what I encountered here.

Now, with the bonuses to Knockback and Elemental Power we don’t see actual numbers, just the four bars. It is possible that the underlying numbers get bonuses that are not represented via the bars and that could explain why a higher-rarity weapon doesn’t seem to have an appropriate number of bonuses. In which case I would say, just show us the numbers for those stats (on hover over the bars if you want to keep the presentation as is). Otherwise, it’s completely incomprehensible how rarity affects a weapon.

It wouldn’t explain, however, why Common weapons have any bonuses at all (at least sometimes). I would have assumed them to be the base weapon that are listed in the Workshop, as Common is the lowest rarity you encounter during a run. But I’ve seen plenty Common weapons with +15 % Damage, +10 % Fire Rate, or +10 % Critical Chance, but also some with no visible bonuses at all.

So, a bit more clarity on how rarities work would be much appreciated, and if they don’t work as they should, I’d be happy to file a bug report.

I've checked with our game designers, and they've let me know that with the next patch on PC (to arrive a little later on consoles), Weapon Rarities will provide a consistent damage bonus per level (probably 10%, but this might be subject to balancing), and not affect other stats.

Hmm, I’m not sure how I feel about that, my first instinct is that it makes rarities rather bland. I don’t mind the different effects rarity can have, it just needs to be represented transparently. But I’ll wait and see how it feels after the patch. In any case, thanks for the info!