What originally prompted the raid was Weaver did not "play ball" with the ATF. He had, in the past, belonged to a white seperatist group. Separatist, not supremacist. They, (ATF), wanted Weaver to give up information on the group regarding weapons the members had, etc. When Weaver refused to be their undercover rat, they nailed him on a barrel length charge on a shotgun he possessed. When he did not appear in court on that charge, that is when the ATF raided his home and murdered his wife, son, and dog. Nice bunch. They attempted to use the weapons charge as bait to get what they wanted from him.
From what I had read at the time, the ATF was more involved in Weaver's decision to sell a sawed off shotgun.
After he repeatedly refused to make one and sell it to an undercover ATF agent, they convinced his employer that he should be let go and he lost his job.
When he couldn't find work and needed the cash he finally agreed to take a hacksaw to the shotgun and sell it for the cash he needed.
It would not take much of a lawyer to win Weaver's settlement with evidence of that action going way beyond entrapment.