I can say that the 92's even in 44&454 are pretty thin at the muzzle .
It seems like I read a requirement at some point , Cut Rifle maybe , that the guide was more or less 2 calibers for muzzle dia up to 30 cal so the .15>< over groove dia would make sense as a standard . The barrel I had in mind at the time would have had to have been cut back about 3" to meet that requirement from 7mm to 35 cal .