The problem with the original request is while both parties/left v right have extremists, the original poster stated fundamentalist/evangelical Christians be the terrorists. That's absurdly unlikely since the object of their religion, Jesus Christ, was largely non-violent. Unlike Muhammed, who cared a path of violence through the 880sAD. Most attempts of "Christian" violence in the US have usually vehemently discouraged by other Christians, who immediately chastise or distance themselves from anyone advocating that.
Most militias are nothing more than weekend shooting groups and or survivalist groups awaiting some sort of disaster or apocalypse (which both are and are not Religious or Christian based! More often not). Timothy Mcveigh was actually asked to leave the Michigan Militia Corp as being to violent and radical. I studied militia groups in college extensively (and this was before and after the OKC bombing and I was going to school in Edmond, OK) and found them ultimately , relatively harmless. I would caveat that some might consider direct reactionary action in the event of near total gun confiscation, but that's not a terribly popular idea in most of the Midwest and south and would cause issues among many in the populous at large.
No, right wing Christian violence, is for the most part, one big media/lefty wet dream.