It is only a post hoc fallacy if it is unproven that guns aren't involved in accidental gun deaths.
Props for trying to use and show good logic, but you failed rather badly in the execution.
I generally contend that most conservatives or people who call themselves conservative suck at constructing logical arguments, and constantly commit logical fallacies. Sorry but your post rather plainly added evidence to support that assertion. I don't think you understand what that fallacy means.
What a post hoc fallacy would look like in this case:
There was a gun in the home.
A child died in the home.
Therefore the gun caused the death.
or similar.
I hope that helps.
You should, if you are going to be serious about actually trying to catch real logical fallacies, go to this website:
http://www.nizkor.org/features/fallacies/post-hoc.html
http://www.nizkor.org/features/fallacies/
Anything that you can actually show is clearly a logical fallacy, I will happily withdraw, and thank you for.
Otherwise... you simply add more evidence to my general assertion regarding "conservatives".