I do believe it may have been an issue, but I think the real and larger issues in Missouri are better explained in area publications, not from heavily conservative one-issue institutions.
And, Holden had been in hot water for a long time - that is why they ran someone against him. Now ya got someone who can compete against Blunt, who has strong name recognition.
All the area sources I could get into made no mention of weapons. Again, it may have been a component, but it wasn't what caused the loss. Gay marriage, gambling, and economic woes and perceived mishandling of economics had much more to do with his departure:
Columbia Daily Tribune
http://www.showmenews.com/2004/Aug/20040804News028.asp A million-dollar inaugural celebration as the state economy was tanking.
Holdenfs flights on state planes while Missourians navigated potholes below.
The hiring of a contractor to run a state jobs hotline that directed calls to operators in India.
Withholding millions in state education funding to balance the budget, then releasing the money days after voters in scores of school districts raised local tax burdens.
Dexter Daily Statesman
http://www.dailystatesman.com/story/1073677.htmlVoters shout: "No to Bob Holden, No to same-sex marriage!"
Associated Press
http://news.yahoo.com/news?tmpl=story&u=/ap/20040804/ap_on_el_gu/primary_rdp_14With 96 percent of precincts reporting, McCaskill had 424,345 votes, or 52 percent, compared to Holden's 371,439 votes, or 45 percent.
The gubernatorial race was part of a full ballot that also included a constitutional amendment to ban gay marriage and a primary to fill the seat of retiring Rep. Dick Gephardt (news - web sites). The gay marriage ban was approved overwhelmingly.
St Louis Post-Dispatch
http://www.stltoday.com/stltoday/news/stories.nsf/News/Election+2004/8CF61C38A1065B0986256EE600053FDC?OpenDocument&Headline=McCaskill+ousts+Holden+in+gov