I'd probably have gotten along with "Old Askins", as he liked to call himself, but I'd make darn sure I stayed on his good side. One Border Patrol Agent who was killed a few feet away from Askins during a gunfight barely got a mention in Unrepentant Sinner, saying he never cared much for the guy. He didn't say he was glad the guy was murdered by contrabadista, but he didn't have anything good to say about him either.
One thing I loved about the Colonel was his ability to poke fun at himself, making awful shots, stupid decisions or verbally shooting himself in the foot. He had a wry sense of humor, understated and clever.
As for guns, he used a lot of shotguns early on, but as was mentioned, didn't seem to have a lasting fondness for any one gun or caliber or gauge, he used whatever was handy, and used it well. One dark night on the Rio Grande found him with a white rag tied around the muzzle of his side-by-side shotgun, so he could tell where it was pointed!
But as for his cold-bloodedness, I guess he was. He was also a racist, in the worst connotation it carries. When asked about the men he'd killed, he said something like, "Twenty-six, not counting (blacks) and Mexicans."
But for all his ugly traits, he was a damn fine pistol shot, accomplished wingshooter, and no one to mess with while he had a rifle, and he unabashedly preferred the heavier calibers. All his books are good reads.
Just don't expect to get any warm and fuzzies from them!
Papajohn