I also personally am against making it random, and am going to throw out my suggestion on how to go about it.
Instead of each shot just winning or losing, each shot has HP equal to its caliber. When two shots collide, the shot with larger caliber loses HP equal to an amount based on the losing shot's caliber. The smaller the losing shot is compared to the winning shot, the less damage the winning shot receives (even 100 pistol shots won't beat a tank). If a shot wins enough clashes that its HP reaches 0, it will be destroyed along with the final shot unless it was of high enough caliber to win anyway. If two colliding shots are equal in caliber or close enough, they both should be destroyed.
This might sound a little complicated but it's really as simple as "you can damage enemy shots to shoot them down, but instead of using the spell's damage stat it goes by the caliber."
It's not a bad idea, but I can think of multiple problems with this one.
First, there's the obvious balance issues..... something that's probably beyond solving this close to release. A major change like that seems very.... heavy.... for such a late point in the beta. I can guess at alot of not foreseen problems popping up with all sorts of spells because of this.
But the other problem is more of how it would work compared to how the current system works. In the current system, let's say, it's me VS a monster that fires out a steady stream of shots at me, whichever monster that might be. In the current system, if I have a higher caliber, I can pop the thing's shots, and bam, it's done. But with an HP system.... it ends up being more like "stand there and keep firing until they EVENTUALLY get through", because you'd have to lower the HP of each shot before they'd break. The challenge here doesnt really increase because of this, it simply takes longer. A system like this is also likely to be completely useless against any enemy that moves too much; you can count on it for enemies that DONT move much, because you know where their bullet stream is going to be, but lots of enemies DO move alot, and often rather erratically... against these foes, there's no point in worrying about caliber if it cant break through in one go, as with a slower system, by the time you break the shots, they're already gone (as in, the enemy has moved to a new position, requiring you to change your aim now). It's simpler just to dodge and hit the enemy directly. Even simple wall crawlers would cause this to sorta break down. I'm not going to try to use shots defensively against enemy bullets either if it takes more than a single strike to pop the shots, either, because that means more time spent firing at the enemy bullets JUST to break them, while other things are still going on and potentially attacking me....
Part of this is as always my own general absolute lack of patience, so keep that in mind, but those are the problems I see with that idea. I would honestly probably just ignore the whole system after a change like that. Doing anything that involves any randomness also is one that seems like it'd be a mistake.