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Went to the range today, shot the scoped 45-70 and the 243 Ultra. The load for the 45-70 was H4198 and the 300gr Nosler partition. A friend had his chrono set up and let me run one of my loads over it, 2318fps. I was still working up in .2gr powder increments, that load of 55.4grs shot a 1¼" 3 shot group at 100yds, after he left I ended up working up to 56.8grs and called it good when 3 shots were touching at 100yds!
The 243 didn't show as much promise shooting H380 and 65gr Vmax, best group was right at 1" with 44gr, above that accuracy dropped off. I also shot some 55gr CT ballistic silvertips, but my starting load was too hot, shot 1" groups, but caused the barrel release to be "sticky" when opening it. The primers were also slightly cratered, but none stuck in the chamber. I'm going to back off a couple grains and try those again with a little less powder unless I find that the powder capacity increased enough in the once fired stuff that my start load isn't close to being compressed. Book max is 53gr, I started at 49gr. This was shooting in new winchester brass, powder capacity was restricted since I was compressing powder at less than 51gr, so I think I'll just neck size these once fired cases and see if the powder capacity will improve and hopefully reduce pressure some. The nosler books shows the 53gr max load as the only compressed load.
Tim
The 243 didn't show as much promise shooting H380 and 65gr Vmax, best group was right at 1" with 44gr, above that accuracy dropped off. I also shot some 55gr CT ballistic silvertips, but my starting load was too hot, shot 1" groups, but caused the barrel release to be "sticky" when opening it. The primers were also slightly cratered, but none stuck in the chamber. I'm going to back off a couple grains and try those again with a little less powder unless I find that the powder capacity increased enough in the once fired stuff that my start load isn't close to being compressed. Book max is 53gr, I started at 49gr. This was shooting in new winchester brass, powder capacity was restricted since I was compressing powder at less than 51gr, so I think I'll just neck size these once fired cases and see if the powder capacity will improve and hopefully reduce pressure some. The nosler books shows the 53gr max load as the only compressed load.
Tim
