Going to meet a guy tonigbt to hopefully get my first 1911. He has 2 rang officers. 1 is the "1 in 500" deal that is .45 the other is 9mm. I'm trading him a SIG556. I really want the 9mm because it's already a caliber I shoot. Would it be wise to get the 45 instead of the 9mm with this perticular 1911?