Weapons

I voluntarily completed a 4 week program 20 years ago to help me stop drinking. I have not drank since then. I recently went to purchase a firearm in July 2009 and was denied because i was in the voluntary program 20 years ago? collect firearms because of there value for my childrens inheritance. I was recently denied because 20 years ago i volunteered to attend a program. The Federal Government is saying that i was there involuntarily which is a lie.The records were supposedly destroyed years ago and the only thing that shows is the dates i participated.

Are air pistols/CO2 pistols considered to be handguns under firearms laws?

What are my rights to defend myself and or my personal property with a registered handgun in the state of Texas? Also if the gun was purchased and registered in the state of Tennessee do I have to also register it in Texas?

How do I transport my guns legally across country?