It works pretty well to me!

Great work c0burn!
Thanks for sharing also the source!
Probably it'd be cool to add a 2nd model pivot argument, so you can position, for example, a gun on the head of an ogre!

PS: I don't know which model you used, but plasma rifle is rotated -180 degrees on y axis. Is it an effect of the merge operation or simply the original model was already rotated?