Even emiya cant do kalashnikov
Yeah, I wonder why. His Archer class should be enough to make him create a projectile weapon.
Well,
technically as far as I know Shirou / EMIYA / Archer
could create guns, pretty much recreate anything thanks to their Projection and Reinforcement magecraft, as a matter of fact I vaguely remember Shirou found Lancer Gáe Bolg beautiful and kinda wanted to copy it
Thing is that in Shirou case his Elemental Affinity and Origin
literally are Sword, pretty sure it's because he had Avalon inside him for many years, because of that he pretty much completely sucks at anything else since he just don't have good affinity for other elements
Because of that Shirou can pretty much only use two magecrafts, Reinforcement which let him analyze and increase the effectiveness of a object, such as making it more durable, and Projection which let him make copies of said objects, his main skill Tracing is basically a higher version of Projection that let him perfectly copy a sword, including its history and skill of its wielder
As a Magus Shirou is basically pretty much inept and incompetent and would never be able to go above apprentice level due to the fact that Avalon made his Elemental Affinity and Origin be Sword, but at the same time that's the reason he can use Unlimited Blade Works since his nature literally is Sword
Also, if you look into EMIYA Alter you'll see he has two guns, they're just modified Kanshou and Bakuya so they technically still count as swords :v
In short they're basically minmaxed for Swords
Also, his class Archer is entirely due to the Holy Grail War, Servants are just extremely powerful so their powers get limited by putting them into classes, so as far as I remember we only really see a fraction of their power due to having their abilities limited
Theorically a Servant can be very different if they were summoned as a different Class, but I don't think we're ever really saw that and Grand Order pretty much threw that out of the window by instead giving us entirely different version of the characters, example, Artoria as Lancer had very different life compared to classic Saber we know
Heracles is a good example of what I mean, if I remember correctly he was forcefully summoned as Berserker but could also have been Saber, Archer, Lancer, Rider and Assassin, which would probably have made him very differently
I might have a detail or two wrong since been a eternity I went deep into Type-Moon, so please someone correct me if I fucked up lol