So far, I am unaware of any of the Branch Davidians, including Koresh, having broken any laws at all. I am also unaware of any so-called "gun law" which is not in direct conflict with the supreme law of the land. As far as I can see, from all reports, a bunch of innocent, American citizens were murdered in cold blood while exercising their Constitutional rights on their private property.
IMO, you have been misled. Koresh did not put bullets, tanks, incendiary devices, and flammable gas into a church full of women and children. The US government under Clinton and Reno did.
The charges of child abuse by Koresh have been thoroughly debunked. They were trumped up as a convenient rationale for actions against the Davidians as were allegations of a drug lab at the church. Both were calculated to increase public sentiment against the sect. Although both charges were retracted, this fact was not widely reported, and many people who relied on mainstream news still believe they were true. Same strategy used against Billy Dale in the WH travel office firings. Ultimately he was acquitted of any wrongdoing but by then the lie had accomplished its purpose.