257 Roberts Ackley Improved load development

ScreaminEagle

ScreaminEagle

Handloader
Jan 20, 2011
1,373
0
If so, could someone give me this combo:

257 Roberts Ackley Improved (40 degree shoulder)
100gr Nosler BT
IMR 4350
CCI 200 LR primers
26" Barrel
Win brass
Not sure what other info is needed

I'm going away for a week, so don't be insulted if I don't reply right away. Thanks in advance.
Steve
 
Code: 
Cartridge          : .257 Roberts Imp.
Bullet             : .257, 100, Nosler BalTip 25100
Useable Case Capaci: 55.684 grain H2O = 3.615 cm³
Cartridge O.A.L. L6: 2.775 inch = 70.49 mm
Barrel Length      : 26.0 inch = 660.4 mm
Powder             : IMR 4350

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   74    38.00   2534    1426   27699   7559     87.2    1.578
-18.0   76    38.95   2593    1493   29423   7806     88.4    1.542
-16.0   78    39.90   2653    1563   31251   8048     89.6    1.506
-14.0   80    40.85   2712    1633   33187   8284     90.8    1.471
-12.0   82    41.80   2772    1706   35240   8515     91.9    1.438
-10.0   84    42.75   2831    1780   37398   8738     92.9    1.404
-08.0   86    43.70   2891    1855   39661   8953     93.9    1.365
-06.0   87    44.65   2950    1932   42053   9160     94.8    1.328
-04.0   89    45.60   3009    2010   44585   9358     95.6    1.292  ! Near Maximum !
-02.0   91    46.55   3068    2090   47266   9547     96.4    1.258  ! Near Maximum !
+00.0   93    47.50   3127    2171   50106   9724     97.0    1.225  ! Near Maximum !
+02.0   95    48.45   3185    2253   53114   9891     97.7    1.193  !DANGEROUS LOAD-DO NOT USE!
+04.0   97    49.40   3244    2336   56303  10046     98.2    1.162  !DANGEROUS LOAD-DO NOT USE!
+06.0   99    50.35   3302    2420   59683  10188     98.7    1.132  !DANGEROUS LOAD-DO NOT USE!
+08.0  100    51.30   3359    2506   63270  10317     99.1    1.103  !DANGEROUS LOAD-DO NOT USE!
+10.0  102    52.25   3417    2592   67078  10432     99.4    1.075  !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     93    47.50   3271    2376   58824   9698     99.8    1.141  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     93    47.50   2940    1919   41537   9318     90.7    1.334
 
Thanks DrMike! I suppose, if I gave you a true OAL and case capacity, we could tweek it a bit? How does one go about measuring case capacity?
 
Weight a clean empty new casing, after weighing fill case with water and reweigh, than you have the H2O capacity after you subtract empty weight from full weight.
Dr. Mikes program has already done this for you based on what is already known about the case.
 
Place your water in an open container overnight to deoxygenate the water. Some people boil it, but I let it set overnight exposed to the atmosphere. Weigh the empty brass with the spent primer in place. If you have a steady hand, you can zero your scale and drop the water in with a pipette until you form a concave meniscus. This is called "maximum case capacity, overflow." Your actual overall length and this maximum case capacity, overflow, allows for a more precise projection.
 
Weigh a fired case and record.
Fill it with H20 and weigh again.

Subtract=case capacity for QL
 
DrMike":2h1ff0yu said:
Place your water in an open container overnight to deoxygenate the water. Some people boil it, but I let it set overnight exposed to the atmosphere. Weigh the empty brass with the spent primer in place. If you have a steady hand, you can zero your scale and drop the water in with a pipette until you form a concave meniscus. This is called "maximum case capacity, overflow." Your actual overall length and this maximum case capacity, overflow, allows for a more precise projection.
Click to expand...


I got some water setting out now. I'll give you some numbers to run this weekend if you don't mind.
Steve
 
Steve,

I suspect you didn't get the Maximum Case Capacity. I would have anticipated somewhat more case capacity. Here is what your data shows, however. Still, it is more than enough velocity to take down any deer in NA.

Cartridge : .257 Roberts Imp.
Bullet : .257, 100, Nosler BalTip 25100
Useable Case Capaci: 53.276 grain H2O = 3.459 cm³
Cartridge O.A.L. L6: 2.775 inch = 70.49 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : IMR 4350

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 75 36.80 2503 1391 27297 7282 86.3 1.581
-18.0 77 37.72 2562 1457 28997 7523 87.6 1.545
-16.0 79 38.64 2621 1525 30801 7760 88.8 1.509
-14.0 81 39.56 2680 1595 32714 7993 90.0 1.474
-12.0 83 40.48 2740 1666 34743 8219 91.1 1.440
-10.0 85 41.40 2799 1739 36895 8439 92.2 1.406
-08.0 87 42.32 2858 1814 39174 8652 93.2 1.368
-06.0 89 43.24 2917 1890 41568 8857 94.1 1.331
-04.0 90 44.16 2976 1967 44092 9053 95.0 1.295 ! Near Maximum !
-02.0 92 45.08 3035 2046 46767 9240 95.8 1.260 ! Near Maximum !
+00.0 94 46.00 3094 2126 49604 9418 96.5 1.227 ! Near Maximum !
+02.0 96 46.92 3153 2207 52613 9584 97.2 1.195 !DANGEROUS LOAD-DO NOT USE!
+04.0 98 47.84 3211 2290 55807 9740 97.8 1.164 !DANGEROUS LOAD-DO NOT USE!
+06.0 100 48.76 3269 2373 59197 9884 98.3 1.133 !DANGEROUS LOAD-DO NOT USE!
+08.0 102 49.68 3327 2458 62800 10015 98.8 1.104 !DANGEROUS LOAD-DO NOT USE!
+10.0 104 50.60 3385 2544 66630 10133 99.2 1.076 !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 94 46.00 3241 2332 58354 9431 99.7 1.142 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 94 46.00 2905 1874 41029 8988 89.8 1.336
 
Did you form a convex (curved upward) meniscus? I anticipated more case capacity. SAAMI Maximum Case Capacity, overflow, is 63.0 grains of water.
 
DrMike":38lz355u said:
Did you form a convex (curved upward) meniscus? I anticipated more case capacity. SAAMI Maximum Case Capacity, overflow, is 63.0 grains of water.
Click to expand...

Yes sir. It is Win +P brass. Thicker walls= less capacity?
 
I hope that I screwed up somewhere. Nosler data states 50gr as max. QL starts saying "do not load" at 46.9
 
SE, I bumped the PSI's up to 62000PSI for a max loading and came up with this. QL lists a 56000 upper end, so adjusting for this, with IMR4350 this is what I came up with. That is using your 60.0 grain H20 capacity.

Cartridge : .257 Roberts Imp.
Bullet : .257, 100, Nosler BalTip 25100
Useable Case Capaci: 52.671 grain H2O = 3.420 cm³
Cartridge O.A.L. L6: 2.775 inch = 70.49 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : IMR 4350

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 81 39.20 2670 1583 32521 7910 89.7 1.480
-18.0 83 40.18 2733 1659 34696 8152 90.9 1.441
-16.0 85 41.16 2797 1737 37008 8386 92.1 1.404
-14.0 87 42.14 2861 1817 39479 8613 93.2 1.361
-12.0 89 43.12 2924 1899 42085 8830 94.2 1.322
-10.0 91 44.10 2987 1982 44841 9038 95.1 1.284
-08.0 93 45.08 3051 2067 47777 9235 95.9 1.247
-06.0 95 46.06 3114 2153 50904 9420 96.7 1.212
-04.0 97 47.04 3177 2241 54239 9593 97.4 1.178
-02.0 99 48.02 3239 2330 57795 9753 98.0 1.145 ! Near Maximum !
+00.0 101 49.00 3302 2421 61591 9899 98.6 1.113 ! Near Maximum !
+02.0 103 49.98 3364 2513 65646 10030 99.0 1.082 !DANGEROUS LOAD-DO NOT USE!
+04.0 106 50.96 3426 2606 69981 10146 99.4 1.053 !DANGEROUS LOAD-DO NOT USE!
+06.0 108 51.94 3487 2700 74621 10246 99.7 1.024 !DANGEROUS LOAD-DO NOT USE!
+08.0 110 52.92 3548 2796 79592 10329 99.9 0.997 !DANGEROUS LOAD-DO NOT USE!
+10.0 112 53.90 3609 2892 84925 10395 100.0 0.970 !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 101 49.00 3438 2624 72429 9676 100.0 1.039 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 101 49.00 3117 2157 50945 9664 93.3 1.210
 
Thanks guys. I'm gonna figure out a load as soon as my scope gets here. I'll let you know the results.
Steve
 
DrMike, I've always just filled a fire-formed case with reverse osmosis filtered water and never thought about the gas content of the water. How significant is the difference?
 
RR, I haven't actually measured the differential. I am going by the notes from Mr. Broemel and from previous determinations of measurements on STP.
 
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