Recommended weight 0.9-1.0, depending on model. I've been getting reports that on other models, lowering the weight to 0.7-0.6 works better. Experiment!
On mine, RoXL, it works best at 0.9, while on BriXL it works better at 1.0. Somewhere in this rough range should work. I also strongly recommend terms like "rifle" and "holding gun" to help guide SDXL.