What are the best 3 things to magically enhance on a firearm?

I've got two factions (well more but they can be divided in two groups).

One faction is the magic faction. They recently learned of more advanced tech and don't want to learn it as it gives their enslave species a better chance of fighting back.

The second faction shows why this is a good idea, as a machinegun is a potent weapon to deal with magic users by sheer volume of power. But this faction isn't very magically gifted and is still learning how to make proper spells.

The second faction is looking to magically enhance their firearms. You have two categories:

Ammo enhancements, which they don't generally do as the ammo is too small to carry much enhancement. Ammo enhancements let you improve the ammo all the way to it's effect on target.

Weapon enhancements. These enhance the weapon. It can also enhance the ammo *as long as it is within the weapon*, the moment it leaves the weapon it loses all enhancements.

The non-magic faction can enhance 3 parts of the weapon by 10%, it cannot do the same characteristic twice. But what would be the most optimal one?

For example of what you can enhance:

- the barrel is 10% heavier. - the barrel is 10% heavier, but only during the recoil phase. - there is 10% less recoil. - the bullet is 10% lighter while in the barrel. - there is 10% more space inside the magazines - the weapon can fire 10% larger bullets than it's physical dimensions allow.

Etc.

With all the variations you can think off, I want to know what 3 elements would be best to improve for a basic small arms firearm. Having less recoil is great... but what would be the best way to accomplish this? Would you be better off with more ammo capacity? Or a 10% faster bullet acceleration? Or a 10% lighter bullet so you can accelerate it faster overall? With such a mind boggling array of potential options, there have to be some that are basically hacks to improve the gun way beyond other options.