An interesting observation

[Varmint Hunter]

As usual, I was endlessly testing bullets and loads yesterday. This time I was working with a 280AI with a 26" Bartlein bbl. I found that the Hornady 162 ELD-M liked to be .015" off the rifling, which I have noticed with ELD-M bullets in other diameters. I loaded up 3 different powders in various charge weights so that I could start low and work up while looking for pressure.

I was shooting at 400yds and had a few groups come in @ 1.3"-1.7", give or take. When I got home, I noticed that ALL of the tight groups had a velocity between 2,935fps and 2,955 fps. It didn't matter that all three powders were at different burn rates.

 

[ShtrRdy]

Interesting observation.

 

[4g64loser]

As usual, I was endlessly testing bullets and loads yesterday. This time I was working with a 280AI with a 26" Bartlein bbl. I found that the Hornady 162 ELD-M liked to be .015" off the rifling, which I have noticed with ELD-M bullets in other diameters. I loaded up 3 different powders in various charge weights so that I could start low and work up while looking for pressure.

I was shooting at 400yds and had a few groups come in @ 1.3"-1.7", give or take. When I got home, I noticed that ALL of the tight groups had a velocity between 2,935fps and 2,955 fps. It didn't matter that all three powders were at different burn rates.

I have found this in other chamberings as well. I have not worked with 280ai specifically beyond helping my friend with fire forming and initial workup on the one I put together for him.

I found the 142 Sierra smk would shoot very well at 2950 give or take 25fps with a bunch of different powders in the 6.5-284. In the 22-250ai, 40gr noslers would hammer at 4200 with 4064, varget, rl15, vvn150, probably some others. 4064 and varget had a higher node at 4400 or a bit over but not every barrel and powder would get there without....unfortunate consequences. The classic 308 m852 match load is famous, and requires little explanation.

This phenomenon is interesting to me as well.

Great shooting with your 280ai.