QL Request, 280 ai, 168 LRX

[NWBlacktail]

Hey guys, can I ask someone to run a QL analysis?

SAAMI 280 Ack Imp
24" barrel
O.A.L. 3.400"
Nosler brass, 66.806 grain H2O
Reloader 26
Barns 168 grain LRX

I'm currently testing at 57 grains, at about 2815 fps, but I have no idea where pressure max is.

Thanks!

 

[DrMike]

Is the measured case volume overflow?

Cartridge          : .280 Ack Imp
Bullet             : .284, 168, Barnes 'LRX'BT 30284
Useable Case Capaci: 56.451 grain H2O = 3.665 cm³
Cartridge O.A.L. L6: 3.400 inch = 86.36 mm
Barrel Length      : 24.0 inch = 609.6 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   82    45.60   2282    1942   29853   9501     94.4    1.607
-18.0   84    46.74   2342    2046   31871   9784     95.6    1.565
-16.0   86    47.88   2402    2152   34045  10048     96.7    1.524
-14.0   88    49.02   2462    2261   36391  10293     97.6    1.483
-12.0   90    50.16   2523    2374   38926  10515     98.4    1.443
-10.0   92    51.30   2583    2489   41666  10713     99.0    1.404
-08.0   94    52.44   2643    2606   44634  10885     99.5    1.365
-06.0   96    53.58   2703    2726   47852  11029     99.8    1.328
-04.0   98    54.72   2763    2848   51344  11145    100.0    1.291
-02.0  100    55.86   2823    2972   55141  11233    100.0    1.251
+00.0  102    57.00   2882    3098   59279  11312    100.0    1.210  ! Near Maximum !
+02.0  104    58.14   2940    3225   63786  11386    100.0    1.171  ! Near Maximum !
+04.0  106    59.28   2999    3354   68725  11456    100.0    1.134  !DANGEROUS LOAD-DO NOT USE!
+06.0  108    60.42   3057    3485   74129  11520    100.0    1.097  !DANGEROUS LOAD-DO NOT USE!
+08.0  110    61.56   3114    3618   80065  11579    100.0    1.062  !DANGEROUS LOAD-DO NOT USE!
+10.0  112    62.70   3172    3754   86563  11631    100.0    1.028  !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    102    57.00   3008    3375   74834  10788    100.0    1.109  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba    102    57.00   2686    2691   46461  11635     97.4    1.333

 

[NWBlacktail]

Mmmm, I think I messed up.

I measured again, and with the water slightly peaking over the mouth I'm at 74.1 grains H2O.

sorry! And thanks for the help!

 

[DrMike]

Cartridge          : .280 Ack Imp
Bullet             : .284, 168, Barnes 'LRX'BT 30284
Useable Case Capaci: 63.739 grain H2O = 4.138 cm³
Cartridge O.A.L. L6: 3.400 inch = 86.36 mm
Barrel Length      : 24.0 inch = 609.6 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   72    45.60   2171    1758   25335   9385     92.5    1.738
-18.0   74    46.74   2225    1847   26863   9693     93.7    1.697
-16.0   76    47.88   2280    1939   28499   9988     94.9    1.658
-14.0   78    49.02   2335    2033   30246  10269     95.9    1.619
-12.0   79    50.16   2390    2130   32113  10535     96.9    1.581
-10.0   81    51.30   2445    2230   34110  10783     97.7    1.543
-08.0   83    52.44   2500    2332   36245  11012     98.4    1.506
-06.0   85    53.58   2555    2436   38538  11221     99.0    1.470
-04.0   87    54.72   2610    2542   40992  11408     99.4    1.434
-02.0   88    55.86   2665    2649   43625  11571     99.8    1.399
+00.0   90    57.00   2719    2759   46452  11710     99.9    1.365
+02.0   92    58.14   2774    2870   49491  11824    100.0    1.332
+04.0   94    59.28   2827    2982   52758  11924    100.0    1.297
+06.0   96    60.42   2880    3095   56276  12021    100.0    1.260  ! Near Maximum !
+08.0   97    61.56   2933    3210   60058  12114    100.0    1.223  ! Near Maximum !
+10.0   99    62.70   2986    3326   64091  12204    100.0    1.188  ! Near Maximum !

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     90    57.00   2855    3041   58117  11198    100.0    1.257  ! Near Maximum !
Data for burning rate decreased by 10% relative to nominal value:
-Ba     90    57.00   2520    2368   36682  11633     95.2    1.485

 

[NWBlacktail]

Thank you sir!

 

[Ridgerunner665]

Here it is with the burn rate adjusted to match your 57 grains at 2,815 fps...Ba set at .362

Cartridge          : .280 Ack Imp
Bullet             : .284, 168, Barnes 'LRX'BT 30284
Useable Case Capaci: 63.745 grain H2O = 4.139 cm³
Cartridge O.A.L. L6: 3.400 inch = 86.36 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Alliant Reloder-26 ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.849% 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

-08.5   85    53.99   2678    2675   45713  11055    100.0    1.387
-07.6   86    54.49   2701    2721   47017  11106    100.0    1.372
-06.8   87    54.99   2724    2768   48354  11157    100.0    1.357
-05.9   88    55.50   2747    2814   49725  11208    100.0    1.342
-05.1   89    56.00   2769    2861   51131  11258    100.0    1.327
-04.2   89    56.50   2792    2908   52574  11307    100.0    1.311
-03.4   90    57.00   2815    2955   54057  11356    100.0    1.294
-02.5   91    57.50   2837    3002   55583  11404    100.0    1.278  ! Near Maximum !
-01.7   92    58.00   2859    3050   57153  11451    100.0    1.262  ! Near Maximum !
-00.8   93    58.50   2882    3098   58769  11498    100.0    1.246  ! Near Maximum !
+00.0   93    59.00   2904    3146   60433  11544    100.0    1.230  ! Near Maximum !
+00.8   94    59.50   2926    3194   62145  11590    100.0    1.215  ! Near Maximum !
+01.7   95    60.00   2948    3243   63908  11634    100.0    1.200  ! Near Maximum !

 

[NWBlacktail]

Thanks Ridgerunner! That's awesome.

I'm using mag primers, I wonder if that was throwing the BR off a bit from prediction. Looks like I have some more room to go, I'll take it slow.

 

[Ridgerunner665]

Primers are of little consequence in calibrated QL predictions... The extra power of the mag primers is accounted for in the adjusted burn rate.

Sent from my XT1585 using Tapatalk

 

[NWBlacktail]

Well, as luck would have it, I left my chrono battery on since last month and it was completely dead when I showed up at the range. Anyway, I shot 3 groups of 3. 58, 58.5, 59 grains RL26. Notice anything funny about the upper right group (58.5)? I'm pretty sure I totally 'Robinhood'ed" all 3 in one hole. I can tell for sure at least 2 went in, I couldn't find another hole anywhere. I know it was just statistical luck, no way I could repeat that. But I think I'll take a better look at that charge. :mrgreen:

 

[SJB358]

Wow, that's gotta make a guy pretty happy!

Can't wait to see more targets.

 

[NWBlacktail]

This is a repeat. This time a five shot group, 3 went into the same hole at the bottom. I did 3 sets of 5, but interestingly the other two groups at 58.5 grains RL26 didn't turn out that well.

I'm starting to think I need to slow down and work on my fundamental shooting skills. This one was pretty good though.

Had the chrono out too, averaged just above 2900 fps (didn't do the statistics yet) at 65 F.

EDIT: 10 shot average = 2903, sd =6.6, group size ended up at 0.65". Probably good enough for cow elk this winter.