You may be staying just around the corner from Reg Barber's shop, but I said nothing about Reg Barber or his tampers . . .
Yikes...bad day?
I was trying to clarify your post as I wasn't sure what 'stock' tamper you were referring to as I was referring to RB tampers so assumed you were as well. And given that you didn't provide any actual measured dimensions, a 'stock' 58mm tamper from uncle Bubba's garage may actually be 57.5 or 58.9mm...
Not sure what's up lately, but some of your responses to peoples posts have been a little on the harsh side. Replies like these tend to make the forum unwelcome to newer members and generally serve no purpose.
Perhaps refrain from replying if you feel you need to talk down to folks?
Hope you have a better day today.
Dave