mwells72774, The 6.5x57 sounds nice but dont you have feeding issues? Also could you PM me the 100gr load data if you still have it? I have a leftover box of 100gr hornadys.
Also what bases did you use for the scope?
Mwells, I load 120 and 129 grain Hornady's and have no feeding problems. I think you could load up to 140 gn bullets and not have feeding problems, as tat was the original jap load. I use 7mm Mauser brass and neck them down and then fire form them blowing out the shoulder. The 6.5x57mm has a shoulder more forward than the 7X57mm Mauser case. My cases must be thicker than normal. I worked up some loads using published Hornady 6.5X57mm load data with the 129 gn bullet. The best load was over 3,100 fps. Published load data had that load was 2,800 fps. The Airsaka actiion handled it fine, but I backed the load to about 2,900+ fps.
I will check on the load data for 100 gn bullets if I still have it. That was before the current Adams & Bennett barrel and re-chambering.
Bases were on the receiver when I purchased it. I would have to remove the scope to be sure, but Weaver #57 seems to come to mind.
Many T-38's were re-chambered to 6.5X257 Roberts in the 50's and 60's. That was the caliber of my rifle when purchased. The Roberts copied the 6.5X 57mm Mauser in creating the 2.57 Roberts and just necked it down to 2.57 as the metric bullets were not popular at the time.