Reaper dude's review below has some faults in his assumptions.
Archer does use gae bolg in side cannon material.
EMIYA and Shirou are capable of true name releases because they project the history of the weapons and skill of the original user.
It's also why he is able to know who a servant is just by glancing at their weapons.

Honestly, shirou totes should have used gae blog. The reversal of cause and effect would negate infinity just by the cheapness of its ability.

People forget this is a spar, not a fight to the death. Why the hell would Shirou want to kill Gojo for a freaking spar, he just the guy. And using Gae Bolg isn't going to be an instant win, especially when it's something that Shirou can't trace so quickly. He hasn't trained himself to properly be efficient regardless of how he absorbed experiences from Archer.

ha thanks for the cap, regarding the comments that gea bolg can kill satoru hey to consider if infinity can interfere with the perception of space that the NP has since that is a way of avoiding it, leaving its range of action Another thing to take into account would be Satoru's ability to use positive energy to heal himself in case Gea Bolg manages to pass infinity and hit his heart since we have seen that Gojo managed to heal from a wound made by a weapon practically made for kill him. now the difference between domain expansion and RM personally is quite easy if we consider that the domain is the maximum form of a spell that interacts with the world, Although this would only be for humans, probably the closest thing to having an RM would be curses since they are basically spirits.

I think people might be overestimating Shirou's ability to use Gae Bolg. After all we know that some Noble Phantasms take longer for Shirou to Project than others and given that I can't remember EMIYA or Emiya ever using Gae Bolg there's probably a reason for that. Also, although Gae Bolg can ignore a lot of defenses and things like that, there are ways to fool Gae Bolg, like how Saber survived it due to her Luck making it so that it only nicked her heart thus fulfilling the requirement of "Always hits the heart" that was also helped by her Instinct predicting where Gae Bolg was going to go through and what its effect was and positioning her sword in light of that. This made it so that although Gae Bolg hits before it's thrust it still somewhat follows the path of the thrust and won't effect the path unless it interferes with the fact that the heart was stabbed. Now admittedly this kind of scenario is not easy to replicate so it doesn't matter most of the time.

Also, just because Shirou can Project a Noble Phantasm it doesn't mean that he can use its True Name. I'm fairly certain that it takes a bit of time for him to figure out how to do that, so passive effects like Kanshou and Bakuya's physical and magical resistance are useful. This is also one of the reasons that Broken Phantasms are so useful as well, since they tend to explode on impact and cause a lot of damage without him needing to use its True Name. Now that's not to say he can't use True Name Releases whatsoever as I'm fairly certain that Caladbolg and Hrunting are both uses of that, as well as maybe Rule Breaker. Just that he can't use the True Name Release of every single Noble Phantasm in his arsenal. The passive abilities of them should work fine though, and just saying the passive abilities are anything that doesn't require the Servant to say the name of the Noble Phantasm, also it has to actually be related to the Noble Phantasm and not just be an ability of the Servant.

Welcome back. Already producing awesome chapters. Worth the wait.

It would be risky for Shirou to use Caladbolg, it's not just a simple noble Phantasm that explodes, but rather, its main quirk is that it is a space bending nuke, as in it twists space itself, allows it to essentially bypass any form of non-physical defenses, ie. Caster's magic shield was easily penetrated as Caladbolg just twisted space, created a hole and bypassed it without even touching it, even if Caster tried teleporting, space would get twisted and she'll end up taking Caladbolg anyways.

Even if Gojo could create an infinite space between them, Caladbolg in this context could be classified as a anti-space manipulation weapon. In which it would be a battle between concepts, which would be a bit difficult as JJK and FSN takes place in completely different universes. There's absolutely no good reason as to why Shirou would risk Gojo's life on the off-chance that Infinity could stop a proven anti- space bending/magic defense projectile

Shirou is a bit too OOC. He's a lot easier to fall into baits and tricks it appears, meanwhile in canon he was able to either look completely apathetic or like he's about to murder dozens of people in front of him while screaming like a madman.

Still felt like Shirou, just Shirou seems to have lost a lot of the characteristic emptiness.

Thanks for the update. Can’t wait for more

why not let out gae bolg?

Thanks for the chapter, I'm enjoying it.

Great chapter, I am curious how much Shirou will tell Nanami.

That was prettt clever. Sucking in the explosion instead of the Caladbolg itself. It would be problematic if he targets the Caladbolg as its already twisting space itself as it travels.

angry mango chan is super op on this world imagine shirou got angry manga chan power

he saw root what true magic he got