Next to last paragraph in the American Rifleman article makes reference to it stating "that Springfield already has plans to produce the pistol in "other popular calibers" in the future, according to Williams." Dave Williams is head of Springfield's custom shop in Geneseo, Ill. (Now I did read into the article as 9mm and 40 S&W are the other most popular calibers.). In due time they are coming. They have already completed the hardest work with the .45acp.
Proudly clinging to my guns and religion !!