The Rovolver Gunax, main weapon of the AWS-G-04 Gundam Gamigin, appear in the mobile game IRON-BLOODED ORPHANS: Urdr-Hunt and in the official Mobile Suit Variation website for Gundam Iron-Blooded Orphans

This has been scale for the MG version of Gundam Barbatos 4th form, but you can scale it to your liking using the scale tool file, which is the same size of the handle. Scale that to your liking then use the ratio for the hammer.

The v2 is longer, has bigger hammer head compare to the standard version but also will be pretty heavy for the MG Barbatos to hold with one hand, so some pose might be limited. The v2 handle is longer, but can be use in exchange with the standard version.