Scaling up luminar crystal weapons came with considerable challenges.
It wasn't so bad at first. Ves first started with scaling up his standard assault rifles to heavy assault rifles.
The former was light enough to allow regular baseline humans to handle them without any significant hindrance. While the weapon was certainly a bit hefty, Zanthar didn't exhibit too many issues when he test-fired the standard rifle.
The latter only looked a bit longer and thicker, but its total volume had scaled up drastically. This caused the weapon to become very dense and heavy, so much so that even Ves felt uncomfortable with handling it despite his augmented strength.
It wasn't just the weight that made it difficult to handle. Its exaggerated proportions and its longer rifle barrel made it harder to balance it in a person's hands.