Load Dev for custom LR 280 AI

[brikwhitt]

Some of you know I've been waiting nearly a year for my custom 280 AI. I finally have it, and I will be mounting a scope this weekend, as well as prepping some Nosler Brass for load development.

This is my goal for my first range session. To find max safe load for my rifle. I will be loading 150gn ABLR over a starting charg of 56gn of R26 and working up to 61.0 gns. I will of course stop whenever I see obvious pressure signs. I will be working up in .3 gn increments. I will be using Fed mag primers to insure good ignition, and shooting over a chrony.

Case prep will consist of uniforming primer pockets, and sorting to a +/- .001 case neck thickness variation.

Not concerned about group size for now. I can work on that later.

Any thoughts or sugestions?

Sent from my SM-N920V using Tapatalk

 

[Michael C. Smith]

Have Fun and enjoy your new rifle and keep us posted on how it all works out!

Sent from my SM-G930V using Tapatalk

 

[SJB358]

I would likely skip the .3 increments to be totally honest. Use 1 full grain increments and see what the speeds show on your chrono.

Since it is an Ackley, you might be able to drive that cartridge very hard before you see traditional signs of pressures, AND RL26 is very tricky stuff since you can keep adding powder and speeds will keep rising without a clue until you hit PSI's which are usually off the charts.

If you are just looking for speeds, I would just chrono them and see where you wanna work at FPS wise, then if you have the need to tweak it, then break it down into smaller increments. Unless you are planning on doing a ladder test or similar I can't see breaking down the charges that small until you are working for an accuracy load. Most of the time the speeds will be hard to see on a chrono with a .3 grain charge in a case the size of the 280 Ackley.

Just me, but I haven't found the need for Magnum primers with standard cases and RL26 yet. Some say they help, but I tried them in the 243, 25-06, 6.5 Swede and 270/7mm WSM and didn't see where they did anything better for me in my rifles, but they certainly shouldn't hurt either.

Have fun and post up your results. Can't wait to see what it does. It's a sweet looking rifle.

 

[brikwhitt]

I would likely skip the .3 increments to be totally honest. Use 1 full grain increments and see what the speeds show on your chrono.

Since it is an Ackley, you might be able to drive that cartridge very hard before you see traditional signs of pressures, AND RL26 is very tricky stuff since you can keep adding powder and speeds will keep rising without a clue until you hit PSI's which are usually off the charts.

If you are just looking for speeds, I would just chrono them and see where you wanna work at FPS wise, then if you have the need to tweak it, then break it down into smaller increments. Unless you are planning on doing a ladder test or similar I can't see breaking down the charges that small until you are working for an accuracy load. Most of the time the speeds will be hard to see on a chrono with a .3 grain charge in a case the size of the 280 Ackley.

Just me, but I haven't found the need for Magnum primers with standard cases and RL26 yet. Some say they help, but I tried them in the 243, 25-06, 6.5 Swede and 270/7mm WSM and didn't see where they did anything better for me in my rifles, but they certainly shouldn't hurt either.

Have fun and post up your results. Can't wait to see what it does. It's a sweet looking rifle.

Thats a good point, and maybe I should do that. I would be happy with the 150gn ABLR in the 3000 fps range. If i can hit an accuracy node somewhere around there with it, i would call it a good day. Maybe someone with quickloads can run it through for me.

3100 fps would be nice, but I like accuracy better if I find it slower.

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[Guy Miner]

As I recall, JD338 has a .280 AI that shoots just terrific! I think he's had it a good 10 years or so, and has made some very impressive long-range shots.

Might be worth looking up his posts & load info?

Guy

 

[brikwhitt]

I think JD is shooting the 160gn AccuBond over R22... as i recall, it works quiet well for him.

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[TackDriver284]

brikwitt, I assume you have a 26 inch barrel and 2nd chart shows pressure max at 65,000
If you have a fired case, H20 capacity would help narrow it down more.
Hope that helps. Can't wait to see results. Good luck.

Cartridge : .280 Ack Imp
Bullet : .284, 150, Nosler AccuBond LR 58734 G7
Useable Case Capaci: 65.284 grain H2O = 4.239 cm³
Cartridge O.A.L. L6: 3.330 inch = 84.58 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : Alliant Reloder-26

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   90    58.50   2830    2667   40514  10929     99.2    1.443
-09.0   91    59.15   2863    2731   42014  11013     99.4    1.419
-08.0   92    59.80   2897    2795   43573  11090     99.6    1.395
-07.0   93    60.45   2930    2860   45197  11159     99.8    1.372
-06.0   94    61.10   2964    2926   46887  11220     99.9    1.349
-05.0   95    61.75   2997    2992   48651  11273    100.0    1.326
-04.0   96    62.40   3030    3058   50490  11317    100.0    1.304
-03.0   97    63.05   3063    3125   52409  11357    100.0    1.282
-02.0   98    63.70   3096    3192   54411  11395    100.0    1.261
-01.0   99    64.35   3128    3259   56500  11433    100.0    1.240  ! Near Maximum !
+00.0  100    65.00   3160    3327   58684  11469    100.0    1.220  ! Near Maximum !
+01.0  101    65.65   3193    3395   60963  11504    100.0    1.200  ! Near Maximum !
+02.0  102    66.30   3225    3463   63347  11538    100.0    1.180  ! Near Maximum !
+03.0  103    66.95   3257    3532   65838  11571    100.0    1.160  !DANGEROUS LOAD-DO NOT USE!
+04.0  104    67.60   3288    3602   68437  11603    100.0    1.141  !DANGEROUS LOAD-DO NOT USE!
+05.0  105    68.25   3320    3671   71141  11633    100.0    1.123  !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    100    65.00   3298    3623   74329  10958    100.0    1.116  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba    100    65.00   2946    2891   45406  11855     97.9    1.359

Cartridge : .280 Ack Imp
Bullet : .284, 150, Nosler AccuBond LR 58734 G7
Useable Case Capaci: 65.284 grain H2O = 4.239 cm³
Cartridge O.A.L. L6: 3.330 inch = 84.58 mm
Barrel Length : 26.0 inch = 660.4 mm

Predicted Data for Indicated Charges of the Following Powders.
Matching Maximum Pressure: 65000 psi, or 448 MPa
or a maximum loading ratio or filling of 110 %
These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

30 loads produced a Loading Ratio below user-defined minimum of 85%. These powders have been skipped.
Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
Alliant Reloder-26                 103.1     66.7     4.32    3246   100.0    65000   11560   1.167  !DANGEROUS LOAD-DO NOT USE!
Norma MRP                          104.0     65.3     4.23    3223   100.0    65000   11729   1.165  !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N560                    105.8     65.1     4.22    3218    98.8    65000   12088   1.161  !DANGEROUS LOAD-DO NOT USE!
PB Clermont PCL 517                108.4     69.6     4.51    3213    99.4    65000   11813   1.153  !DANGEROUS LOAD-DO NOT USE!
SNPE Vectan SP 12                  108.2     69.5     4.51    3212    99.4    65000   11791   1.153  !DANGEROUS LOAD-DO NOT USE!
ReloadSwiss RS 70                  100.8     64.6     4.19    3210   100.0    65000   11350   1.153  !DANGEROUS LOAD-DO NOT USE!
Accurate MAGPRO                    106.0     67.8     4.40    3207    97.7    65000   12155   1.167  !DANGEROUS LOAD-DO NOT USE!
IMR 7828 SSC                       104.4     64.5     4.18    3201    99.1    65000   11669   1.152  !DANGEROUS LOAD-DO NOT USE!
Bofors RP5/NP ~approximation       106.1     64.5     4.18    3191    99.7    65000   11595   1.167  !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-22                 106.1     64.5     4.18    3191    99.7    65000   11595   1.167  !DANGEROUS LOAD-DO NOT USE!
Raufoss RA15                       106.1     64.5     4.18    3191    99.7    65000   11595   1.167  !DANGEROUS LOAD-DO NOT USE!
IMR 7828                           110.0     64.3     4.17    3191    99.0    64260   11647   1.158  ! Near Maximum !
Bofors RP15                        108.9     64.9     4.20    3190    99.6    65000   11613   1.168  !DANGEROUS LOAD-DO NOT USE!
Winchester WXR                     108.9     64.9     4.20    3190    99.6    65000   11613   1.168  !DANGEROUS LOAD-DO NOT USE!
ADI AR 2213                        105.3     64.1     4.15    3185    99.0    65000   11578   1.152  !DANGEROUS LOAD-DO NOT USE!
ReloadSwiss RS 60                   94.5     59.7     3.87    3179   100.0    65000   10424   1.160  !DANGEROUS LOAD-DO NOT USE!
ADI AP 2214                        109.1     68.1     4.42    3173    99.1    65000   11378   1.150  !DANGEROUS LOAD-DO NOT USE!
Ramshot Magnum                     105.6     69.2     4.48    3166    99.9    65000   11009   1.160  !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-25                 110.0     65.8     4.27    3157   100.0    60342   11178   1.194  ! Near Maximum !
Rottweil R905                      107.3     64.1     4.15    3154    98.6    65000   11320   1.168  !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-17                  93.5     59.0     3.82    3154   100.0    65000   10353   1.168  !DANGEROUS LOAD-DO NOT USE!
Elcho 17                            93.5     59.0     3.82    3154   100.0    65000   10353   1.168  !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-23                 108.7     64.0     4.15    3152   100.0    65000   10416   1.174  !DANGEROUS LOAD-DO NOT USE!
Bofors RP5 NT ~approximation       109.0     66.9     4.33    3147    97.3    65000   11438   1.157  !DANGEROUS LOAD-DO NOT USE!
ADI AR 2209                        102.2     61.2     3.97    3146    99.6    65000   10996   1.159  !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-19                 102.8     61.9     4.01    3144    99.6    65000   11062   1.167  !DANGEROUS LOAD-DO NOT USE!
PB Clermont PCL 518                 99.1     61.6     3.99    3140   100.0    65000   10741   1.172  !DANGEROUS LOAD-DO NOT USE!
PB Clermont PCL 511                 95.2     61.0     3.95    3137   100.0    65000   10659   1.173  !DANGEROUS LOAD-DO NOT USE!
Bofors RP14 ~approximation         103.6     62.3     4.04    3136    99.6    65000   10981   1.167  !DANGEROUS LOAD-DO NOT USE!
Ramshot Hunter                      98.3     61.1     3.96    3135   100.0    65000   10644   1.173  !DANGEROUS LOAD-DO NOT USE!
Hodgdon H414                        92.9     59.1     3.83    3134   100.0    65000   10699   1.174  !DANGEROUS LOAD-DO NOT USE!
Winchester 760                      92.9     59.1     3.83    3134   100.0    65000   10699   1.174  !DANGEROUS LOAD-DO NOT USE!
ReloadSwiss RS 62                   96.9     61.1     3.96    3134   100.0    65000   10423   1.185  !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-16                 100.0     58.6     3.80    3132   100.0    65000   10208   1.178  !DANGEROUS LOAD-DO NOT USE!
Norma 204                           97.5     60.6     3.93    3118    99.5    65000   10780   1.168  !DANGEROUS LOAD-DO NOT USE!
Raufoss RA4                        100.7     60.6     3.93    3118    99.5    65000   10780   1.168  !DANGEROUS LOAD-DO NOT USE!
Bofors RP4 ~approximation          100.7     60.6     3.93    3118    99.5    65000   10780   1.168  !DANGEROUS LOAD-DO NOT USE!
Hodgdon H4831 SC                   103.9     63.2     4.10    3116    98.4    65000   10923   1.165  !DANGEROUS LOAD-DO NOT USE!
Hodgdon H4831                      108.1     63.2     4.10    3116    98.4    65000   10923   1.165  !DANGEROUS LOAD-DO NOT USE!
Somchem S365                       100.0     59.8     3.88    3115   100.0    65000    9872   1.184  !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N550                     95.1     58.5     3.79    3111   100.0    65000   10326   1.184  !DANGEROUS LOAD-DO NOT USE!
Norma URP                           97.9     58.3     3.78    3110   100.0    65000   10188   1.180  !DANGEROUS LOAD-DO NOT USE!
Bofors RP19 ~approximation          97.9     58.3     3.78    3110   100.0    65000   10185   1.180  !DANGEROUS LOAD-DO NOT USE!
Accurate 4350                       97.0     58.4     3.78    3105   100.0    65000   10133   1.196  !DANGEROUS LOAD-DO NOT USE!
Somchem S385                       103.0     62.7     4.06    3103    99.9    65000   10529   1.186  !DANGEROUS LOAD-DO NOT USE!
Bofors RP4 NT ~approximation        98.3     60.1     3.89    3092    99.9    65000   10347   1.180  !DANGEROUS LOAD-DO NOT USE!
Winchester Supreme 780             101.2     64.2     4.16    3091    99.5    65000   10486   1.173  !DANGEROUS LOAD-DO NOT USE!
IMR 4831                           102.7     59.2     3.83    3090   100.0    65000    9956   1.189  !DANGEROUS LOAD-DO NOT USE!
Rottweil R904                      101.6     60.3     3.91    3087    98.9    65000   10530   1.170  !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N570                    110.0     69.8     4.52    3087    93.3    53685   12660   1.258
Accurate 3100                      106.1     63.8     4.14    3086   100.0    65000   10172   1.200  !DANGEROUS LOAD-DO NOT USE!
SNPE Vectan SP 11                   91.6     56.9     3.69    3085   100.0    65000    9823   1.179  !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N165                    108.3     64.5     4.18    3085    99.8    65000   10276   1.178  !DANGEROUS LOAD-DO NOT USE!
Norma MRP 2                        110.0     66.2     4.29    3081    98.3    55267   11781   1.252  ! Near Maximum !
Bofors RP30                        110.0     66.2     4.29    3081    98.3    55267   11781   1.252  ! Near Maximum !
IMR 4955 Enduron                   105.2     61.6     3.99    3079    98.5    65000   10600   1.170  !DANGEROUS LOAD-DO NOT USE!
Ramshot Big Game                    88.6     56.8     3.68    3079   100.0    65000    9717   1.180  !DANGEROUS LOAD-DO NOT USE!
Hodgdon H4350                      100.3     59.1     3.83    3076    99.9    65000   10171   1.173  !DANGEROUS LOAD-DO NOT USE!
Lovex S070                          97.6     58.1     3.77    3076   100.0    65000   10168   1.188  !DANGEROUS LOAD-DO NOT USE!
IMR 4895                            88.4     53.2     3.45    3076   100.0    65000    9753   1.185  !DANGEROUS LOAD-DO NOT USE!
IMR 4350                            98.5     58.9     3.82    3075    99.9    65000   10149   1.174  !DANGEROUS LOAD-DO NOT USE!
ReloadSwiss RS 52                   89.0     55.3     3.58    3071   100.0    65000    9567   1.188  !DANGEROUS LOAD-DO NOT USE!
Bofors RP11 ~approximation          89.3     53.7     3.48    3070   100.0    65000    9719   1.184  !DANGEROUS LOAD-DO NOT USE!
Raufoss RA11                        89.3     53.7     3.48    3070   100.0    65000    9719   1.184  !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-15                  89.3     53.7     3.48    3070   100.0    65000    9719   1.184  !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N160                    108.4     62.5     4.05    3068    98.8    65000   10326   1.174  !DANGEROUS LOAD-DO NOT USE!
Hodgdon H380                        90.5     55.7     3.61    3068   100.0    65000    9852   1.188  !DANGEROUS LOAD-DO NOT USE!
Bofors RP7 NT ~approximation        92.6     56.2     3.64    3067   100.0    65000    9867   1.162  !DANGEROUS LOAD-DO NOT USE!
Norma 203B                          89.6     54.0     3.50    3064   100.0    65000    9643   1.186  !DANGEROUS LOAD-DO NOT USE!
Hodgdon Hybrid 100V                100.4     58.5     3.79    3061   100.0    65000    9378   1.182  !DANGEROUS LOAD-DO NOT USE!
PB Clermont PCL 516                 87.4     56.0     3.63    3060   100.0    65000    9750   1.179  !DANGEROUS LOAD-DO NOT USE!
IMR 4451 Enduron                    94.3     56.1     3.64    3058   100.0    65000    9977   1.171  !DANGEROUS LOAD-DO NOT USE!
ReloadSwiss RS 50                   90.6     56.7     3.67    3057   100.0    65000    9866   1.182  !DANGEROUS LOAD-DO NOT USE!
Rottweil R907                       95.5     56.4     3.65    3057    99.9    65000   10043   1.182  !DANGEROUS LOAD-DO NOT USE!
Bofors RP7                          95.5     56.4     3.65    3057    99.9    65000   10043   1.182  !DANGEROUS LOAD-DO NOT USE!
IMR 4007 SSC                        92.5     56.4     3.66    3056    99.9    65000   10036   1.182  !DANGEROUS LOAD-DO NOT USE!
Somchem S361                       100.4     64.4     4.17    3053    98.3    65000   10321   1.182  !DANGEROUS LOAD-DO NOT USE!
IMR 4320                            91.2     54.0     3.50    3050   100.0    65000    9380   1.172  !DANGEROUS LOAD-DO NOT USE!
Elcho TR140 - preliminary data      90.2     56.0     3.63    3050   100.0    65000    9595   1.184  !DANGEROUS LOAD-DO NOT USE!
ADI AR 2206H                        86.7     52.1     3.38    3050   100.0    65000    9496   1.183  !DANGEROUS LOAD-DO NOT USE!
Lovex S065                          96.6     56.9     3.68    3050   100.0    65000    9770   1.188  !DANGEROUS LOAD-DO NOT USE!
Bofors RP3                          90.8     55.2     3.58    3049   100.0    65000    9482   1.200  !DANGEROUS LOAD-DO NOT USE!
Norma 203 old                       90.8     55.2     3.58    3049   100.0    65000    9482   1.200  !DANGEROUS LOAD-DO NOT USE!
Hodgdon H4895                       86.3     51.9     3.36    3048   100.0    65000    9441   1.184  !DANGEROUS LOAD-DO NOT USE!
Ramshot TAC                         85.1     55.2     3.58    3046   100.0    65000    9690   1.178  !DANGEROUS LOAD-DO NOT USE!
Rottweil R903                       92.8     55.2     3.58    3044   100.0    65000    9397   1.200  !DANGEROUS LOAD-DO NOT USE!
SNPE Vectan SP 9                    87.3     54.2     3.51    3042   100.0    65000    9422   1.181  !DANGEROUS LOAD-DO NOT USE!
Bofors RP3 NT ~approximation        94.2     56.3     3.65    3042   100.0    65000    9585   1.174  !DANGEROUS LOAD-DO NOT USE!
Somchem S355                        93.1     54.8     3.55    3041   100.0    65000    9427   1.194  !DANGEROUS LOAD-DO NOT USE!
SNPE Vectan SP 7                    85.6     55.2     3.58    3040   100.0    65000    9516   1.190  !DANGEROUS LOAD-DO NOT USE!
ADI AR 2208                         91.9     53.7     3.48    3037   100.0    65000    9415   1.175  !DANGEROUS LOAD-DO NOT USE!
Hodgdon VARGET                      92.2     53.7     3.48    3037   100.0    65000    9415   1.175  !DANGEROUS LOAD-DO NOT USE!
IMR 4166 Enduron                    93.6     54.0     3.50    3033   100.0    65000    9661   1.174  !DANGEROUS LOAD-DO NOT USE!
IMR 4064                            92.7     52.7     3.41    3027   100.0    65000    9221   1.180  !DANGEROUS LOAD-DO NOT USE!
Lovex S071                         110.0     62.6     4.06    3027   100.0    60486   10111   1.239  ! Near Maximum !
Somchem S341                        85.6     55.4     3.59    3025   100.0    65000    9167   1.185  !DANGEROUS LOAD-DO NOT USE!
ADI AR 2217                        110.0     65.5     4.24    3019    97.7    55220   11037   1.238
Hodgdon H1000                      110.0     65.5     4.24    3019    97.7    55220   11037   1.238
Lovex S062                          90.3     52.9     3.43    3014   100.0    65000    9076   1.194  !DANGEROUS LOAD-DO NOT USE!
IMR 8208 XBR                        85.4     51.4     3.33    3009   100.0    65000    8985   1.182  !DANGEROUS LOAD-DO NOT USE!
Lovex D073.6                        86.1     53.4     3.46    3007   100.0    65000    8918   1.205  !DANGEROUS LOAD-DO NOT USE!
Norma 201                           87.7     51.6     3.35    3006   100.0    65000    9046   1.196  !DANGEROUS LOAD-DO NOT USE!
Accurate 2700                       92.6     58.1     3.77    3005    99.8    65000    9475   1.187  !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-33                 110.0     71.8     4.65    3004    92.5    50270   12283   1.298
IMR 7977 Enduron                   109.4     65.1     4.22    3004    92.0    65000   10170   1.176  !DANGEROUS LOAD-DO NOT USE!
IMR 3031                            88.4     49.8     3.22    3003   100.0    65000    8746   1.195  !DANGEROUS LOAD-DO NOT USE!
Accurate 4064                       90.2     53.1     3.44    2998   100.0    65000    8895   1.221  !DANGEROUS LOAD-DO NOT USE!
Rottweil R902                       89.4     51.9     3.36    2997   100.0    65000    8933   1.197  !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N150                     98.1     55.7     3.61    2994   100.0    65000    8886   1.194  !DANGEROUS LOAD-DO NOT USE!
Bofors RP2 NT ~approximation        86.8     51.9     3.36    2992   100.0    65000    8863   1.179  !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N540                     89.2     54.3     3.52    2989   100.0    65000    8922   1.194  !DANGEROUS LOAD-DO NOT USE!
Lovex S060                          87.6     51.3     3.32    2988   100.0    65000    8854   1.178  !DANGEROUS LOAD-DO NOT USE!
Norma 202                           87.0     51.5     3.34    2986   100.0    65000    8762   1.195  !DANGEROUS LOAD-DO NOT USE!
Rottweil R901                       85.8     49.1     3.18    2968   100.0    65000    8618   1.205  !DANGEROUS LOAD-DO NOT USE!
Hodgdon Benchmark                   85.0     50.4     3.27    2968   100.0    65000    8603   1.183  !DANGEROUS LOAD-DO NOT USE!
ADI AR 2225                        110.0     66.6     4.31    2965    99.1    47944   11517   1.321
Hodgdon Retumbo                    110.0     66.6     4.31    2965    99.1    47944   11517   1.321
Vihtavuori N140                     89.0     52.5     3.40    2957   100.0    65000    8439   1.195  !DANGEROUS LOAD-DO NOT USE!
ReloadSwiss RS 80                  110.0     71.8     4.65    2953    92.2    47897   12114   1.326
Vihtavuori N135                     94.4     51.5     3.34    2942   100.0    65000    8221   1.207  !DANGEROUS LOAD-DO NOT USE!
ADI AR 2218                        110.0     70.5     4.57    2928    89.6    48365   12223   1.316
Lovex D100                         110.0     71.2     4.62    2919    88.0    55890   10412   1.255  ! Near Maximum !
Somchem S335                        87.5     51.5     3.34    2918   100.0    65000    8149   1.203  !DANGEROUS LOAD-DO NOT USE!
Vihtavuori 24N41                   110.0     70.5     4.57    2890    85.0    51246   10851   1.292
Norma 217                          110.0     65.2     4.22    2866    97.1    41885   11540   1.416
Vihtavuori N170                    110.0     65.5     4.24    2854    90.4    50075   10414   1.333
Hodgdon H870                       110.0     68.4     4.43    2838    91.3    42540   11535   1.406
Hodgdon US 869                     110.0     70.5     4.57    2688    80.7    41269   10095   1.436
Hodgdon 50BMG                      110.0     67.2     4.35    2687    76.4    41426   10047   1.432
SNPE Vectan SP 13                  110.0     67.6     4.38    2633    85.1    37409    9971   1.505
Accurate 8700                      110.0     69.1     4.48    2603    83.7    37106    9880   1.504
PB Clermont PCL 513/520/9520       110.0     67.6     4.38    2564    81.8    35197    9655   1.547
NC A3502 ,test only                110.0     64.8     4.20    2351    57.0    33197    7338   1.595

 

[SJB358]

brikwitt, I assume you have a 26 inch barrel and 2nd chart shows pressure max at 65,000
If you have a fired case, H20 capacity would help narrow it down more.
Hope that helps. Can't wait to see results. Good luck.

Just as a note, RL26 in QL is quite high in charge weight for me. Dewey has the formula BA that works pretty well across the board, but I ran into PSI at my start loads using 26 when it first came out. It is worth backing off 5-6 grains from the QL data in my opinion. The speeds listed are attainable, but you will likely get there with less powder. I like 26 alot, where it fits, it works and is FAST!

 

[TackDriver284]

brikwitt, I assume you have a 26 inch barrel and 2nd chart shows pressure max at 65,000
If you have a fired case, H20 capacity would help narrow it down more.
Hope that helps. Can't wait to see results. Good luck.

Just as a note, RL26 in QL is quite high in charge weight for me. Dewey has the formula BA that works pretty well across the board, but I ran into PSI at my start loads using 26 when it first came out. It is worth backing off 5-6 grains from the QL data in my opinion. The speeds listed are attainable, but you will likely get there with less powder. I like 26 alot, where it fits, it works and is FAST!

Yes it is high, its why I asked if he had a fired case to tweak it some more. It's easy to change Ba to match chrono velocity. Starting low, as you mentioned, and working up loads is always the safest and wise way because its unpredictable.

 

[brikwhitt]

I have no fired case yet, but maybe in a week or so I will. I'll get you an H2O copacity after shooting the first time out. Velocity will be easy once I shoot over my chrony. Thanks for the help. Right now Im just looking for a good start powder weight and estimated max.

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[Dwh7271]

Dewey has the formula BA that works pretty well across the board,

Around .355-.360 will be fairly close although there are still variances. At least those numbers should keep you from blowing primers and such. :grin:

 

[brikwhitt]

Dewey has the formula BA that works pretty well across the board,

Around .355-.360 will be fairly close although there are still variances. At least those numbers should keep you from blowing primers and such. :grin:

Ouch! Maybe I should start with more of a sure thing? I have 7828ssc and 4831sc although I know i probably wont hit the speed I'm looking for with the kind of accuracy I want.

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[Dwh7271]

If you would like an opinion, try Scotty's idea.
Start around 58 and work up every half to full grain. I'm guessing you'll get where you're looking for around 60-61 gr, but work up. I have no idea about your chamber so be careful.
I think 26 will do what you want.

 

[Dwh7271]

This should get you going.
Get a case capacity and a few chrono readings and we can tighten this up for you.

Cartridge          : .280 Ack Imp
Bullet             : .284, 150, Nosler Accubond LR 58734
Useable Case Capaci: 65.284 grain H2O = 4.239 cm³
Cartridge O.A.L. L6: 3.330 inch = 84.58 mm
Barrel Length      : 26.0 inch = 660.4 mm
Powder             : Alliant Reloder-26 ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.729% 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

-07.3   92    59.38   2981    2959   49085  10767    100.0    1.330
-06.6   93    59.85   3004    3005   50429  10801    100.0    1.314
-05.8   93    60.31   3026    3050   51818  10835    100.0    1.298
-05.1   94    60.78   3049    3096   53242  10868    100.0    1.283
-04.4   95    61.25   3071    3142   54702  10900    100.0    1.268
-03.6   95    61.72   3094    3188   56199  10932    100.0    1.253  ! Near Maximum !
-02.9   96    62.18   3116    3234   57736  10963    100.0    1.238  ! Near Maximum !
-02.2   97    62.65   3138    3280   59316  10994    100.0    1.224  ! Near Maximum !
-01.5   98    63.12   3161    3327   60940  11024    100.0    1.209  ! Near Maximum !
-00.7   98    63.58   3183    3374   62610  11054    100.0    1.195  ! Near Maximum !
+00.0   99    64.05   3205    3421   64327  11083    100.0    1.181  !DANGEROUS LOAD-DO NOT USE!
+00.7  100    64.52   3227    3468   66093  11112    100.0    1.168  !DANGEROUS LOAD-DO NOT USE!
+01.5  100    64.98   3249    3515   67909  11140    100.0    1.154  !DANGEROUS LOAD-DO NOT USE!
+02.2  101    65.45   3271    3563   69778  11168    100.0    1.141  !DANGEROUS LOAD-DO NOT USE!
+02.9  102    65.92   3292    3610   71700  11195    100.0    1.127  !DANGEROUS LOAD-DO NOT USE!
+03.6  103    66.38   3314    3658   73679  11221    100.0    1.115  !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     99    64.05   3269    3559   72307  10845    100.0    1.130  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba     99    64.05   3125    3252   56483  11374    100.0    1.241  ! Near Maximum !

 

[brikwhitt]

Dwh thanks for your help. Whenever I do get to the range, i'll give you aome muzzle velocities. And I'll try and get you a fired case water weight. Another thing, I decided to start at 3.340 coal.

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[Dwh7271]

Glad to.
Shouldn't be big between 3.33 and 3.34.
We'll get you better numbers with capacity and some speeds.

 

[TackDriver284]

Glad to.
Shouldn't be big between 3.33 and 3.34.
We'll get you better numbers with capacity and some speeds.

Did you use the 3.55 - 3.60 Ba? Mine was a standard Ba without the case capacity. Glad you could help out. It was hard for me to tell without owning a 280 AI. It was the best I could do.

 

[brikwhitt]

So are we at a consensus that 58gn start 61gn max should be a good safe change? I will look at the velocity and allow that to help guid me. Looks like 3200 fps is a safe max, so if I see 3100 on the chrony, I can assume Im still under safe max with a little headspace. Unless I'm grossly mistaking. Hope my accuracy node will be somewhere in that range. Maybe someone with experience shooting that combo will chime in and tell me where they found their accuracy node.

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[NWBlacktail]

So are we at a consensus that 58gn start 61gn max should be a good safe change?

Easily. that's about my min/max with the 168 grain bullets and RL26. I just barely hit pressure at 60.5 grains RL26 and 168 grain Berger VLD.

For me, 24" barrel, 168 grain Berger VLD, Nosler brass, Fed 215 primers. Pressure is at 2950 fps using 60.5 grains RL26.

hope this helps, good luck!

 

[brikwhitt]

So are we at a consensus that 58gn start 61gn max should be a good safe change?

Easily. that's about my min/max with the 168 grain bullets and RL26. I just barely hit pressure at 60.5 grains RL26 and 168 grain Berger VLD.

For me, 24" barrel, 168 grain Berger VLD, Nosler brass, Fed 215 primers. Pressure is at 2950 fps using 60.5 grains RL26.

hope this helps, good luck!

Thanks NWBlacktail, makes me feel better about the whole thing.

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