I've got a .40 cal with a 1in18 twist.The barrel I won at a blanket shoot.Unmarked,homemade by a man named Les Franz.I did all the machine work to breech it and such.Then mounted it in an old El Cheapo Spanish pistol.Used their brass hardware and built my own trigger assembly.It looks like the pistol everybodies had at least one of,except it shoots like a house afire!!Noah