Best bet is probably to try to figure it out based on void/cyber/sentgun since they all have the same speed. At least that'll take out speed from the equation (for the time being).

What's messing with me is how Sunblessed Bow can give Blast a high of 293 while SentGun gives Blast a high of 294. Perhaps here's a case where speed plays a part? It almost looks like there's some kind of cap to how much a skill can be increased, in terms of damage, regardless of future possible weapons? Ugh. I hope not.

Maybe the extra Dex and Crit from SentGun plays a role?