I believe that an EMP is impractical due to the crazy power draw. Non-nuclear EMPs are typically explosively pumped and have a very short range. Jammers (which is what the radio gun is) could work, but are civilian-illegal.
Since that is currently the high-water mark in 2nd amendment rights on the pro-side, I assume you can point us to reversals since then, apparently occurring on a daily basis?
Please, share your sources with the group.