You would need both modern weapons and modern men to use them. The tactical side of the equation is as important as the tactical.
Consider the "breechloader question" that Civil War buffs are so fond of debating -- would the adoption of breechloaders have given the North an even greater advantage?
The answer can be found by watching the movie "Gallipoli" with Mel Gibson. In the climactic scene, the Australians are preparing for the attack -- Lee-Enfield rifles with fixed bayonets leaning against the paraphet, scaling ladders in place for climbing out, officers and NCOs checking and rechecking everything.
The battalion commander comes walking down the trench and asks if one thing has been checked.
If you were a battalion commander, what's the one thing you would want checked?
I'll give you his words (the actual battalion commander actually said them, in the real battle), "Has anyone checked to see that these rifles are unloaded? This is supposed to be a bayonet attack, you know."
If you're not going to load your rifles, what difference does it make if you don't load them at the breech, or you don't load them at the muzzle?
Tactics didn't catch up to the capability of the breechloading rifle until very late in the war, and didn't really blossom until the invention of field radios, which allowed commanders to control widely spread out troops.