Gentlemen:
I have a question about loading for the 8.15X46R Schuetzen rifle. First, I know from the moderate bit of reading done on this cartridge that the 8.15X46R (marked as 7.7 on the underneath side of the barrel) was far from standardized. My rifle was made in the late 1920s and the barrel slugs at 0.305" bore and 0.316" grooves. From what I have read, sometimes the bore on rifles so chambered can go up to 0.323". My chamber cast reveals that the throat is large and funnel-shaped with plenty of room to accommodate a 0.323" boolit. The mouth of a fire-formed case measures at 0.323".
I know that some shooters of these great old rifles breech seat the bullet and then place a charged case with card wad behind it. Others use a stop-ring bullet that finger presses into the mouth of a charge cartridge just before shooting. Do any of you Schuetzen-ators out there have an idea if this chamber and bore combination was intended for one method or the other?
I have always chosen a rifle boolit to fit the groove diameter plus one thousandth more and got good results, but am trying to rationalize all the measurements that seem a bit contradictory. Tom, over at Accurate Molds, lists three different stop-ring boolit molds of similar diameter and style on page 5 of his online catalog. They are all dimensioned, it seems, for the larger bore diameter. The 8.15X46R Schuetzen target rifle typically shoots a boolit of approximately 180 grains at around 1,400 fps, so the chamber pressure surely is not that great. Is the rifle made to use a boolit that is around seven thousandths of an inch over bore / groove diameter so that the long leade and smaller bore swage the boolit down? Do I need to order a mold in the customary manner of one thousandth of an inch over groove diameter? Any help would be appreciated.