Safe Load?

hunter24605 · Oct 11, 2023

This seems it might be pushing the envelope. But it's very accurate and there is zero signs of pressure.
280 AI 22" barrel
Nosler brass, H20 75.0 grain, Trimmed 2.525
Speer 160 gr Grand Slam
CCI 34
COAL 3.330
63.3 Gr Reloder 26
Velocity 2995 fps

Maybe someone can run QL to see where it's at..
Hopefully it's safe, I can't think of much that would shake it off.

JD338 · Oct 11, 2023

Sounds like a great load Howie.
Guess we will see what QL says.

JD338

RL338 · Oct 11, 2023

Not near my computer now , but the 280AI is almost a clone of the 7mm RM and that velocity would be right inline. RL26 is the Dr. Feelgood of powder.

hunter24605 · Oct 11, 2023

RL338 said:
Not near my computer now , but the 280AI is almost a clone of the 7mm RM and that velocity would be right inline. RL26 is the Dr. Feelgood of powder.

I’m pretty sure it’s safe, but velocity seems a little high with a 22” tube. Down to 2 lbs of 26

RL338 · Oct 11, 2023

hunter24605 said:
I’m pretty sure it’s safe, but velocity seems a little high with a 22” tube. Down to 2 lbs of 26

Going to have to savor it. Alliant must have shelved the idea of making more.

TackDriver284 · Oct 11, 2023

hunter24605 said:
This seems it might be pushing the envelope. But it's very accurate and there is zero signs of pressure.
280 AI 22" barrel
Nosler brass, H20 75.0 grain, Trimmed 2.525
Speer 160 gr Grand Slam
CCI 34
COAL 3.330
63.3 Gr Reloder 26
Velocity 2995 fps

Maybe someone can run QL to see where it's at..
Hopefully it's safe, I can't think of much that would shake it off.

It's a tad over max pressure ( 65,000 psi is max ), your test charge is 67,121 psi . I recommend backing off a little.
I did some research, according to Optimal Barrel time chart, your node for the 22 inch barrel is 1.1270 which is 62.2 grains, you might want to test close to that charge weight, 1.1 grains less than your test charge.

Code:

Cartridge          : .280 Ack Imp
Bullet             : .284, 160, Speer GRSLAM 1638
Useable Case Capaci: 69.153 grain H2O = 4.490 cm³
Cartridge O.A.L. L6: 3.330 inch = 84.58 mm
Barrel Length      : 22.0 inch = 558.8 mm
Powder             : Alliant Reloder-26 *C ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0   83    56.97   2721    2631   47934  12870    100.0    1.282
-09.0   84    57.60   2749    2685   49589  12947    100.0    1.261
-08.0   85    58.24   2777    2740   51297  13022    100.0    1.242
-07.0   86    58.87   2805    2795   53060  13096    100.0    1.222
-06.0   87    59.50   2832    2850   54880  13170    100.0    1.203
-05.0   88    60.14   2860    2905   56760  13243    100.0    1.185  ! Near Maximum !
-04.0   89    60.77   2887    2961   58700  13314    100.0    1.166  ! Near Maximum !
-03.0   90    61.40   2914    3017   60704  13385    100.0    1.149  ! Near Maximum !
-02.0   91    62.03   2941    3073   62774  13455    100.0    1.131  ! Near Maximum !
-01.0   91    62.67   2968    3130   64912  13523    100.0    1.114  !DANGEROUS LOAD-DO NOT USE!
+00.0   92    63.30   2995    3187   67121  13591    100.0    1.097  !DANGEROUS LOAD-DO NOT USE!
+01.0   93    63.93   3022    3244   69403  13658    100.0    1.081  !DANGEROUS LOAD-DO NOT USE!
+02.0   94    64.57   3048    3302   71762  13723    100.0    1.064  !DANGEROUS LOAD-DO NOT USE!
+03.0   95    65.20   3075    3360   74200  13788    100.0    1.049  !DANGEROUS LOAD-DO NOT USE!
+04.0   96    65.83   3102    3418   76722  13851    100.0    1.033  !DANGEROUS LOAD-DO NOT USE!
+05.0   97    66.47   3128    3476   79329  13913    100.0    1.018  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba     92    63.30   3093    3400   81778  13158    100.0    1.012  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     92    63.30   2845    2876   52481  14225    100.0    1.215