Doesn't say by how much, and it still won't be enough because max out Dual Xbow is the fastest shooting.
https://www.reddit.com/r/ddo/comment...ight_vs_heavy/
Type Bolts Seconds Bolts/Second
Single Light xbow 300 267 1.1235
Dual Light xbows 300 150 2
Single Heavy xbows 300 268 1.1194
Dual Heavy xbows 300 164 1.82
Light Repeater 300 129 2.3255
Heavy Repeater 300 130 2.307
This was with a level 4 character without all the goodies that enhance that to stupid levels.
Dual Shooter was SSG's attempt to make Light / Heavy XBows competitive against Great/Repeating builds and it was far too big of an increase. The second shot should only proc 50% of the time, not a full 100% with all the double shot silliness. There is a reason half the games population is running inquisitives as their DPS build, instead of mechanic or archery. You can't hand waive away all those drones running around with their arms permanently stuck in front of themselves like some sort of robot shooting out long streams of bolts nonstop.