09-17-2013, 03:52 AM
XcountryRider Wrote:Looking at my notes i understated the 100gr Nosler data (30.5gr H335) in my 18in i cronyed 3 rounds and they were 2775, 2750 and 2793. Thats a pretty large ES as well. The ES in my 18in was better using the 123gr Amax with 2554, 2551 and 2555fps which is pretty good. .
That load is close to what Hodgdon's lists as max safe loads in a 20" barrel, with an average of 2744fps. So you're getting faster than a 20" barrel, with evident erratic velocities with only 3 samples. That's evidence of excessive pressure, and makes me think even more that you have a tight bore. The question then becomes, how much more pressure than 49,700psi did you hit to exceed 20" velocity with .2gr less powder? I would dial that one down as well. Think again about me when I saw the chrono spitting out 2580fps from my 16" with a 123gr factory load, but with erratic ES close to 100fps. It would have been awesome if it was stable, but it wasn't.
Hornady's 9th Edition data for an 18" barrel shows a max safe load of 29.6 grs of H335 under 100gr going 2650fps.
If you mean the factory 123gr A-MAX, then those 3 samples are definitely in the range you want, but with a larger sample, like a 10-round string. If the ES stays in the singles or low doubles, you have a good longer range load right there with the factory A-MAX, which is also an amazing hunting bullet in the real world. It expands extremely well, retains weight well, and penetrates well...consistently.