I was able to get a working prototype of this put together.
Here's the buff code. You'd need to setup your timing, weapon effects and what the weapon should do.
https://dl.dropboxusercontent.com/u/5790092/Temp/ArtifactWeaponPrototype.7z
I couldn't get this to work Z. I duplicated the ability file for the shrine artifact (AbilityArtifactShrineAttach), tried to attach the ability to the shrine artifact... but when it attaches to a capital ship absolutely nothing happens.
In your buffs (PostTarget, PreTarget & AttachTarget) I couldn't find reference to BuffArtifactWeaponSelf or BuffArtifactWeaponTarget.
BuffArtifactWeaponAttachPostTarget makes reference to the BuffArtifactShrineAttachTarget buff. PreTarget also includes reference to another Shrine buff.
BuffArtifactWeaponAttachTarget references BuffArtifactShrineSpreadCulture?