This is my third Mauser 66 and it feels like a keeper. Others were a minty (but with unacceptably blonde wood) 30-06 Stutzen and a far too heavy 8x68 rifle. I will leave it as a .270. I shoot short barrel fullstock carbines in at least 10 different calibers, including .270 and 9.3x62. I realize some calibers are more or less efficient in the short barrel but they are all very effective 3-shot hunting rifles. I own a couple of dozen vintage Stutzens from various European manufacturers. That said, I would never rebore any of my Mannlicher-Schoenauers. Did you experience any problems with the conversion or were the .270 and 9.3x62 cases close enough in size so that it wasn't a problem smoothly feeding from the rotary magazine?