I spy with my little eye the spear of loginus

You know. Considering that even fictional heroes can be summoned as servants and the nature of UBW is not of creating blades but materializing what is in Shirou's mind he can technically possible for him to create this and just about any other real or fictional weapons to use in mass.

I mean sure, it is Unlimited BLADE Works, but maybe he can expand his horizons to include guns and etc. I mean Shiki from Tsukihime possibly can cause even non-living beings to cease to exist even though it is more likely trying to do that will kill the guy but it is not impossible. So why couldn't Shirou push UBW into a whole new level?

UBW is badass enough. Just imagine a near infinity number of guns pointed right at the enemy's face. That would be cool.

Observing said:
You know. Considering that even fictional heroes can be summoned as servants and the nature of UBW is not of creating blades but materializing what is in Shirou's mind he can technically possible for him to create this and just about any other real or fictional weapons to use in mass.

I mean sure, it is Unlimited BLADE Works, but maybe he can expand his horizons to include guns and etc. I mean Shiki from Tsukihime possibly can cause even non-living beings to cease to exist even though it is more likely trying to do that will kill the guy but it is not impossible. So why couldn't Shirou push UBW into a whole new level?

UBW is badass enough. Just imagine a near infinity number of guns pointed right at the enemy's face. That would be cool.

He probably just lacks the mana to do so.

Well, UBW can store different things than swords like this shield, which even resist Gae Bolg, but because Shirou´s element is "swords" (don´t ask why), he gets an malus on storing other things.

Shiro's power is to replicate things that he has saw before right? To replicate a specific item, he needs to understand how does the thing works and how does it looks like. Guns, however, are more complicated than swords. Swords are static and solid while guns got many little parts that moves in order to shoot bullets. You can't use simple imaginations to recreate guns. Just replicating the appearence of a gun won't make it shoot, so you need to replicate the little parts inside of the gun.

Maybe that's why Shiro specializations are blades and not guns. He don't specifically understands about them.

But muskets and old age's guns are much simpler than modern guns, so....maybe he can if it were an old guns.

makkun, you just forget about Tracing and reinforcement...

makkun said:
Shiro's power is to replicate things that he has saw before right? To replicate a specific item, he needs to understand how does the thing works and how does it looks like. Guns, however, are more complicated than swords. Swords are static and solid while guns got many little parts that moves in order to shoot bullets. You can't use simple imaginations to recreate guns. Just replicating the appearence of a gun won't make it shoot, so you need to replicate the little parts inside of the gun.

Maybe that's why Shiro specializations are blades and not guns. He don't specifically understands about them.

But muskets and old age's guns are much simpler than modern guns, so....maybe he can if it were an old guns.

The reason Shirou is more in tune with building and replicating swords is due to Shirou's personality being very similar to the purpose of a sword (I believe even Shirou mentions this fact in the VN though don't quote me on it). His impulsive need to sacrifice himself for the sake of others or protect other people from danger is said to be similar to a sword. Keep in mind that reality marbles and marble phantasms in general are magics that rewrites or projects into reality in the image of the mage's inner world. So because of this, it is easier for Shirou to recreate swords and blades compared to other objects. If by some chance Shirou undergoes a drastic personality change that fits the concept of a gun better than a sword, the reality marble would probably change into a field of guns/muskets instead of swords. For example, the UBW of Shirou and Archer while similar, are somewhat different as Shirou's field looks like the moment of sunrise, representing his belief in his ideals, while Archer's is covered in smog and cog wheels, a representation of mechanical and cynical nature.

The complexity of a weapon is of no concern to Shirou in terms of reproducing it. It's because Shirou has a better affinity to swords that they cost less mana to recreate and more quickly prepared. With his Structural Grasp Magecraft that allows him to analyze objects and reinforced eyesight, complexity of a weapon is not really an issue for him.

makkun said:
Shiro's power is to replicate things that he has saw before right? To replicate a specific item, he needs to understand how does the thing works and how does it looks like. Guns, however, are more complicated than swords.

Like making a gun could be more complex then creating Excalibur. Plus in his reality marble he creates an UNLIMITED number of blades... I would say being able to create an infinite number of swords in just a few seconds is good enough to say he can do some pretty complex things.

Technicaly creating something in his realty marble shouldn't cost anything at all (that's the whole point of having it). The only cost there should be is the projection(tracing). And if archer can create other non swordlike equipment (like Rhio Aias) a gun shouldn't be much trouble wouldn't it?

I'd say that it's because
a) The only magical gun we know of was Kiritsugu's, which he never saw, and there certainly isn't a Gun NP (besides Lancelot's Knigh of Honour hax), given the Age of Heroes is over.
b) Any NP is leagues ahead of a gun, even the anti-unit ones
c) Most things he fights are immune to non-magical weaponry, be it through regen (Undead etc) or incorpreality (Servants)
d) Would require him to constantly be retracing bullets

That, and Shirou's ideal is based around the concept of "sword", better explained by takamachi above. What WOULD be interesting is if the dream cycle he shares with Saber let him see when Lancelot uses the plane or the twin SMGs. Given they become Noble Phantasms, there's the possibility he could trace them as E ranked Phantasmic weaponry.

"I am the bone of my soul
Steel is my body and dust is my blood
I have created over a thousand ribbon
Unknown to Grief, Nor known to Life
Have withstood pain to create many weapons
Yet, those hands will never hold anything
So as I pray, unlimited musket works."