Oldtrader3
Ammo Smith
- Nov 6, 2009
- 8,406
- 6
Elmer, even with the cold barrel flyers, you are still close to MOA. I have had a couple of rifles that shot out of the group with a cold barrel. However, you are still Minute-of-a Red-Deer to 400 meters. I have had some luck by allowing loaded rounds to sit for several weeks before testing for grouping in order to increase the galvanic (corrosion) sticktion between neck and bullet shank. Sometimes this helps grouping by inceasing the breakaway tension of the neck.
Your 51.0 grain of IMR 4831 load is way off-book-load in charge size and would have to be chronogaphed to check velocity but would bet that it is over 3000 fps. The .257 Roberts is the most underloaded case of any which I can think of in terms book loading data. The powder that interests me for that 110 grain bullet is Hodgdon's Hybrid 100V. Published data puts the 110 AccuBond at 3100 fps+ with no pressure issues.
Being a relatively new powder, it may be more difficult to get in the U.K.?
Your 51.0 grain of IMR 4831 load is way off-book-load in charge size and would have to be chronogaphed to check velocity but would bet that it is over 3000 fps. The .257 Roberts is the most underloaded case of any which I can think of in terms book loading data. The powder that interests me for that 110 grain bullet is Hodgdon's Hybrid 100V. Published data puts the 110 AccuBond at 3100 fps+ with no pressure issues.
Being a relatively new powder, it may be more difficult to get in the U.K.?