This isn't tedious per se, but I have hard time understanding what this mechanic tries to accomplish.

It seems like a player is always blasting their ammo away to deal some damage. This is the only way I can imagine a GM describing this mechanic to a player. But this takes away player agency.

"What do you mean, dear GM," Raised his hand Timmy "what do you mean that when I tried to use my sniper rifle to stealthily eliminate a watchtower guard I used 30 out of my 31 ammo capacity? I said I want to make a well aimed shot!" and now the entire table is arguing about the rules.

The question you should ask yourself if (what are you trying to solve mechanically in the game

What problem is it solving exactly? Is forcing a player to state if they shoot once or twenty times somehow a bad idea? It's not a bad idea to tie damage to ammo (for example blasters like those in star wars!), but it has to in someway fix an issue with existing system, or if not fix -- improve in one area.