Alpha Sigma Chi was originally founded in 1868. It was the first fraternity of noted Greek Historian, William Raimond Baird (yes the Baird behind Baird's Manual). In 1879 after research was done by Baird, Alpha Sigma Chi chose to merge with Beta Theta Pi. Baird felt that no other union would be as good as that between his beloved ASX and Beta.
Click
here to find out more about the union of Beta Theta Pi and Alpha Sigma Chi.
I don't know how you may feel about this historical note, but it is something that played an important part in the history of my fraternity. While I don't think anything of you using those letters, others might. However don't let that discourage you if your heart is set on those letters.