280 AI Range Day / Pressure Opinions??

[MAinAR]

This is 3rd trip with this load and it has been excellent so far.

280 AI
27" Brux Sendero barrel
215gm primer
Once fired Nosler Brass
63.3 grains of RL 26 (case "feels/shakes" like probably over 97% full)
140AB
.080 off lands
OAL approx 3.33
Magento Speed velocities but groups tested with out it!

Avg MV at 3,260 fps and ES's have stayed under 20fps on 3 test trips.

You guys gave QL data that put this load needing like 66gr to hit this speed but I am getting it at 63.3 so any ideas/opinions on where you think pressure is?????

200 yard group (3 sessions have stayed under .6 moa for three 3 shot groups)

 

[JD338]

Look at the primer pockets. Are they still tight after 4 loadings?

JD338

 

[MAinAR]

Look at the primer pockets. Are they still tight after 4 loadings?

JD338

On the 4th loading with only neck sizing the primer pockets are fine.

 

[JD338]

Perfect!

JD338

 

[Ridgerunner665]

Yep... As JD said... You're fine.

I'm pretty sure I could safely hit that velocity with 140's in a 24" barrel.

 

[Dwh7271]

Cartridge : .280 Ack Imp
Bullet : .284, 140, Nosler AccuBond 59992
Useable Case Capaci: 66.211 grain H2O = 4.299 cm³
Cartridge O.A.L. L6: 3.330 inch = 84.58 mm
Barrel Length : 27.0 inch = 685.8 mm
Powder : Alliant Reloder-26 ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 77 50.64 2615 2125 29018 9211 97.2 1.646
-18.0 79 51.91 2682 2236 31108 9435 98.1 1.602
-16.0 81 53.17 2748 2348 33362 9636 98.8 1.560
-14.0 83 54.44 2815 2463 35790 9812 99.4 1.518
-12.0 85 55.70 2880 2579 38412 9962 99.8 1.474
-10.0 87 56.97 2945 2697 41244 10084 100.0 1.426
-08.0 89 58.24 3009 2816 44306 10180 100.0 1.381
-06.0 91 59.50 3073 2935 47618 10267 100.0 1.337
-04.0 93 60.77 3135 3056 51208 10352 100.0 1.295
-02.0 95 62.03 3197 3178 55061 10433 100.0 1.255
+00.0 96 63.30 3258 3301 59192 10510 100.0 1.216 ! Near Maximum !
+02.0 98 64.57 3319 3425 63640 10584 100.0 1.178 ! Near Maximum !
+04.0 100 65.83 3379 3550 68431 10655 100.0 1.142 !DANGEROUS LOAD-DO NOT USE!
+06.0 102 67.10 3439 3677 73600 10721 100.0 1.108 !DANGEROUS LOAD-DO NOT USE!
+08.0 104 68.36 3499 3805 79184 10783 100.0 1.075 !DANGEROUS LOAD-DO NOT USE!
+10.0 106 69.63 3558 3935 85223 10841 100.0 1.042 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 5% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 5% relative to nominal value:
+Ba 96 63.30 3326 3439 66572 10280 100.0 1.162 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba 96 63.30 3174 3131 51986 10791 100.0 1.278

 

[sask boy]

MAinAR, that is some fine shooting at 200 yards :wink:. With ABs I always try run them out as longs as I can. And as the others guys are saying there should not be a pressure problem.

Blessings,
Dan

 

[nvbroncrider]

No problems there man run it. You might even to push her a touch more but your definitely fine. The difference might be caused if the original QL was ran with a 24" vs 27" barrel.

 

[SJB358]

Looks pretty danged good. You've got to be happy with that!

 

[efw]

Perfect!

JD338

+1

If I wonder whether I'm stepping on it too hard I'll pull several random cases from my chosen lot & fire them first when I go to the range. This allows me to see how the load performs under different conditions and to see how primer pockets hold up. After 4x loaded w/o loose pockets I know I'm safe; make that 8 and I know I'm golden, especially if accuracy has been predictable.

Nice load ha got there; I have a lb of RL23 that needs testing thru my .280AI!