don1885 wrote on Apr 27
th, 2016 at 10:31pm:
One more question Frank. I have a very nice traditional Ballard with a barrel that has no marks of any kind - obviously somewhat later than the original barrel. It slugs to a 0.294" bore diameter, would it meet the T-28 rules assuming the case and rifle configuration will?
That's a real tough one, Don. It's something I hadn't even considered but, should have thought about, considering that it's a caliber limited class of "Elite" shooting
In the day that 28 calibers where used in Schuetzen, bore and grooves were not tightly controlled. As a nominal standard, I would say that a .280 bore and a .288 groove would be about maximum. Most people building rifles, will use 7mm barrel, of .276 bore and .284 groove. So, using logic, we could give a +/- .004 tolerance (.284/.288) and and say maximum could be .292 and your only .002 from that is if, your .294 is your groove diameter.
Before I give a diffident answer, I'd like to hear form owners of original 28/30 rifles, what their groove diameters are and I'd also like to hear from the people that have shot their T-28's since this class started.
I just thought to look at the Lyman/Ideal, as cast mold sizes and this is a picture of the listings for 7mm/28 caliber. first colum is mold #, second as cast, thrid number is as cast for a mold marked "U", last number is the nose punch. .290 is the largest as cast mold.
Frank