Welcome to the forum Jeff,
Here is a link to a Buhmiller article here.
Buhmiller I have a rifle by the late Floyd Butler of Poultney, VT. Floyd was an old time smith who used Buhmiller barrels and indeed said that he had put one on my cherished high wall that he chambered in .22 R2 Lovell. It has a beautiful stock in the style of the era by Butler. Someone rechambered it to .219 Improved RCBS Zipper before I got it. The twist is 1-16" and it shoots the 50 gr Sierra spitzer very well.
Here it is. The barrel is not marked Buhmiller but just has the Butler info on it. Its very accurate.