280 Remington test results

[Wis65x55]

280 Remington test
Powder charge Chronograph velocity
57 gr H4831
Shot 1 3018 Mean 2980
Shot 2 2961 SD 26.87
Shot 3 2961
Group size .99”

58gr H4831
Shot 1 3066 Mean 3031
Shot 2 3023 SD 22.17
Shot 3 3005
Shot 4 3030
Group size 1.01”

58.5gr H4831
Shot 1 3045 Mean 2930
Shot 2 2845 SD 84.2
Shot 3 2901
Group size 1.17

Powder lot change
Powder charge Chronograph
57 gr H4831
Shot 1 2940 Mean 2938
Shot 2 2933 SD 3.9
Shot 3 2942
Group size 1.03”


58gr H4831
Shot 1 2906 Mean 2942
Shot 2 3052 SD 79
Shot 3 2869
Group size 1.28”

Federal Ammunition 150gr bullet

Shot 1 2959 Mean 2874
Shot 2 2758 SD 113.1
Shot 3 3012
Shot 4 2767
Group size 1.84”

Notes: 65degrees F, 24” barrel length, Weatherby Mark V, three shot groups 140gr Nosler PT bullet OAL 3.295+/- .005

Keith

 

[DrMike]

Your rifle definitely likes the velocity in and near 2940 to 2980. It is a definite MOA shooter. Your technique appears to be quite good; your standard deviations are quite good, especially at the lowest charge.

 

[FOTIS]

Start with the 57 gr load and play with seating depth

 

[Wis65x55]

If I miss the target, I can only call it operator error:cry
Recommendations on seating depth change?
Keith

 

[SJB358]

I would go .010 at a time until you start opening up. Split the difference with the two best with a .005" movement in between. I haven't ever had to move more than that once I found my powder charge. Great shooting! It looks like a keeper!

 

[DrMike]

How far off the lands are you now?

 

[Wis65x55]

Presently I am .185" from the lands.
Keith

 

[DrMike]

That is a long jump. How did you select that distance? Is this dictated by the magazine?

 

[Wis65x55]

OK, Math is not my strongest suit. Actually .085 off the lands sorry.

 

[DrMike]

That could still be a fair jump for a Partition. Is there any possibility you can load to 0.010 inches off the lands? If so, that might be a good place to start. If not, then you will have to play with charge, seeking minute charge changes.

 

[Wis65x55]

The longest that I can consistently cycle is 3.322"
Keith

 

[JD338]

That could still be a fair jump for a Partition. Is there any possibility you can load to 0.010 inches off the lands? If so, that might be a good place to start. If not, then you will have to play with charge, seeking minute charge changes.

+1 to what DrMike said.

JD338