What some members are touching on are rather complicated and large optical assemblies. Use the search bar at the bottom of the site and search the term 6x C lens.Hmm. So I need some correcting optics. What would that entail? Is it another lens in use along with the one I'm already using?
Another option depends on how secure your module is in the gun. Sanwu 3x beam expander. This would allow you to set the focus on the internal lens once and make adjustments to the convergence distance by the beam expander. I have them on 90% of my handhelds. This would provide the results you are looking for without having to poke at the internal lens you have. They only come in stainless steel so you would have to match it to the hosts theme somehow. I can put up some pics to paint the picture if you need.