I thought I'd open a new thread for my final report on this Arisaka action with a .257 Roberts chamber and barrel. The old thread had a lot of replies and a new thread would be less cumberson to read. My last time out I used a new powder (RL15) with the 80 grain Barnes TSX pellets and one of the three shots groups with 40 grains of powder was a .75" group. I need to do some final tweeking on the load but this will most likely be the final load. I'm going to play with the OAL a bit.
I last reported that the 80 grain bullets were a significant improvement but I was getting a third shot flyer that opened the group to 2-3". I did a careful reinspection of the stock and found what appeared to be a very small scuff mark where the rectangular hole was to allow for the bottom of the barrel protrusion for the iron sight mount. I dug it out a bit with the dremel tool before I went to the range. My flyer problem went away.
This rifle was a very good learning expierence for me. I want to thank all you guys for all the good information and suggestions you gave me on this issue. It's so nice to have access to so many knowleadgeable persons who share my interests and are so willing to help someone out.
