I agree that we should do a fairly standard rifle for our primary firearm. Not sure if we should go for semi-auto, though- this is WWI tech, bolt-action might be better.
For our sidearm, though, I'd like to do something a bit more flashy.
Gravite Shortsword: Swords! Outdated, obsolete, purely decorative! Such is the prevailing wisdom.
The prevailing wisdom has failed to take into account the existence of Gravite.
Gravite is a metallic substance with unusual properties. However, until recently, it was no more than a curio; Gravite objects weigh different amounts depending on their orientation, which has for centuries baffled scientists. However, recent breakthroughs in theoretical physics indicated that Gravite might be more than just a curio- it might be one of the most important substances on the planet. An eccentric physicist by the name of Ernesto Pondus recently penned an article describing a theory of gravity that overturns the conventional model- something about family members? Professor Pondus also indicated that, properly treated, Gravite could be used to warp the effects of gravity significantly. By subjecting molten Gravite to a strong, mono-directional source of radiation, the molecules can be aligned, turning the random effects on gravity into a consistent, controllable phenomenon.
We've done this, creating bars of solid Gravite that float upwards, in defiance of conventional physics. The applications are endless, but for now, we've found a more humble usage- swords. By smithing bars of Aligned Gravite properly, one can create a blade that projects a gravitational field around itself that deflects objects with some force- crucially, sufficient force to bend the trajectory of bullets. A soldier holding a Gravite Shortsword in front of themselves is significantly less likely to get hit by enemy fire, to the point where it becomes possible to charge forth and smite the enemy with the sword's reasonably sharp blade.
Eh? Eh? I shouldn't need to point out the other potential applications of a gravity-manipulating substance.