Raimey;
You made your post while I was writing mine. Let me see if I am following you. When you say that ("248" IS the plug gauge diameter for 7mm) are you here referencing the older gauge system. If so then 248ga would translate to .266". This would make sense, but all references I have to this system only go down to .300" caliber & are in .010" increments with the gauges carried out to 2 decimal places. My 8x58R (1907) is marked 172.28 (.300") with the actual bore falling between that & 156.14 (.310").
Do you have references for other caliber markings used of smaller dia than 30 claiber, as several existed prior to the switch over in marking?
