as a general school of thought its simplest if you basically go with one of the standard "tech levels" and then make "cosmetic" adaptions to the races gear.
if for the sake of argument your race is about 3 ft tall or so most equipment could or should be ~1/2 to 3/4 size (depending on tech base) and likely should suffer a bit in actual performance. IE their "rifle" should be more comparable with a pistol or carbine in range /damage etc.
on the other hand if the race is bigger than "normal" they might tend to make stuff a bit larger as well in most ways it will be a wash, but what if they "specialize" in a certain tech, you might give them a small bonus, but it should be something that is really minor in most cases and every advantage should have a corresponding disadvantage
for instance in the old d6 star wars rpg, the standard blaster pistol did 4d6, heavy blaster pistols did 5d6ish, and blaster rifles typically did ~5d6 damage, well the "small race" might have their blaster pistol doing 3d6, vs 4d6 and if you pickup a standard blaster pistol, its large and heavy/awkward for you to use.
The larger race might have issues using standard off the shelf blasters but their equivalent might do 5d6 damage comparable to a heavy blaster pistol at the expense of ammo capacity or similar.
to be honest in a way I am rather surprised to see so many people using slug throwing (physical projectile) weapons because from everything I have read they are normally considered primitive, weapons and normally only used in "special cases"