I've measured several of these 88s that were marked with the 'S' on the ring, and all were ~0.327"-0.328" groove diameter. Ditto the several 8x56 1908 Mannlicher-Schoenauers that I've owned and shot. It's my impression that most of these very early 8mms were over-grooved to deal with the fouling from the early ammo.
Actually I was so disenchanted with the seemintly oversize dimension of my first M-S 1908 that I had it rebored to 9x57 before even shooting it. Fortunately by the time I acquired my second 1908 I had also acquired enough sense to shoot it first before any reboring. Of course it was quite accurate with 0.323" bullets.
Regards, Joe
Last edited by J.D.Steele; 02/14/12 10:13 PM.
