The Expanded Clip Epic Feat was a significant contributor to the rate of fire performance problems with Repeating Crossbows. It no longer adds an extra shot, and instead grants +33% stacking Doubleshot with Repeating Crossbows.
I just wanted to note that this is a substantial nerf just on the numbers, without even looking at on-hit procs and the like, even though on the surface it may seem like it's commensurate. E.g. adding an extra shot is +33% damage, adding 33% doubleshot is also +33% damage. The problem comes in because the extra shot is +33% damage
after doubleshot is taken into account, where +33% doubleshot is +33% damage
before doubleshot is taken into account.
For a simple thought experiment, consider an artificer with the old and new expanded clip feat with 100% doubleshot:
Old: 4 attacks at 100% doubleshot = 8 attacks
New: 3 attacks at 133% doubleshot = 7 attacks (3 guaranteed double hits is 6, and an average of one additional hit from the 33% over 3 attacks)
It gets worse as you scale up doubleshot, with 300% doubleshot:
Old: 4 attacks at 300% doubleshot = 16 attacks
New: 3 attacks at 333% doubleshot = 13 attacks