Graham, your grandfather probably joined voluntarily for patriotic reasons and/or to get the $50. The Confederate conscription law was not passed until April 1862 so he was in no immediate danger of being drafted. However, Farragut's Union fleet began assembling off the Louisiana coast in March 1862 in preparation for the attack on New Orleans. There probably was something of a rush of volunteers about that time to defend the city. However, by joining the 6th Louisiana, he must have known he would be going to Virginia.