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| quote: Originally posted by sambarman338: Does anyone here have access to Quickload? Would you mind running a couple of equations in it for me?
In trying to devise a Win 748 load for cast slugs in my Miroku 86 Winchester .45-70, I've been urged to ask someone to run two sets of data for it, one to 28,000 psi and another to 40,000.
The lubricated, gas-checked bullets (from a Redding/Saeco No.19 mould) weigh 468 grains and will be seated to .585" below the mouth of Starline brass that is 2.095" long.
A poster on Cast Boolits says a Brian Pierce has found Starline cases to have a mid-range total volume of 77.5 grains of water.
My Winchester Short Rifle's barrel is 24 inches long.
I'll post on the Lever Action and Big Bores forums, too, but to keep the conversation focused and aid RIP's Mission, would appreciate your answering on the Big Bores forum 458 Winchester Magnum thread.
Thanks in anticipation
Seeing 30.06king's post on 300 magnum loads, it occurs to me to mention I'll be using CCI No. 250 magnum primers, which seem to be indicated for use with W748. |
| Posts: 5161 | Location: Melbourne, Australia | Registered: 31 March 2009 |
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One of Us
| Cartridge : .45-70 Govt. SAAMI
Bullet : .457, 451, LYM LRN GC 457406
Useable Case Capaci: 54.843 grain H2O = 3.561 cm
Cartridge O.A.L. L6: 2.770 inch = 70.36 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Winchester 748
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 38.92 1311 1787 14898 2579 76.5 2.425
-18.0 73 39.89 1347 1884 15882 2683 78.1 2.352
-16.0 75 40.87 1382 1984 16928 2787 79.6 2.283
-14.0 77 41.84 1417 2086 18037 2890 81.1 2.216
-12.0 79 42.81 1452 2192 19213 2991 82.6 2.152
-10.0 80 43.79 1488 2300 20463 3091 84.0 2.091
-08.0 82 44.76 1523 2411 21790 3188 85.4 2.032
-06.0 84 45.73 1559 2524 23200 3283 86.7 1.975
-04.0 86 46.70 1594 2641 24700 3376 87.9 1.920 ! Near Maximum !
-02.0 88 47.68 1630 2760 26295 3465 89.1 1.867 ! Near Maximum !
+00.0 89 48.65 1665 2881 27992 3552 90.2 1.817 !DANGEROUS LOAD-DO NOT USE!
+02.0 91 49.62 1701 3005 29796 3635 91.3 1.768 !DANGEROUS LOAD-DO NOT USE!
+04.0 93 50.60 1736 3132 31729 3715 92.3 1.721 !DANGEROUS LOAD-DO NOT USE!
+06.0 95 51.57 1771 3261 33786 3791 93.2 1.675 !DANGEROUS LOAD-DO NOT USE!
+08.0 97 52.54 1807 3392 35983 3862 94.1 1.632 !DANGEROUS LOAD-DO NOT USE!
+10.0 98 53.52 1842 3526 38331 3930 95.0 1.589 !DANGEROUS LOAD-DO NOT USE! |
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One of Us
| Cartridge : .45-70 Govt. SAAMI
Bullet : .457, 451, LYM LRN GC 457406
Useable Case Capaci: 54.843 grain H2O = 3.561 cm³
Cartridge O.A.L. L6: 2.770 inch = 70.36 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Winchester 748
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 80 43.36 1472 2252 19908 3048 83.4 2.117
-18.0 82 44.44 1512 2375 21353 3157 84.9 2.050
-16.0 84 45.53 1551 2501 22899 3264 86.4 1.986
-14.0 86 46.61 1591 2630 24554 3367 87.8 1.925 ! Near Maximum !
-12.0 88 47.70 1630 2762 26327 3467 89.1 1.867 ! Near Maximum !
-10.0 90 48.78 1670 2898 28228 3563 90.4 1.810 !DANGEROUS LOAD-DO NOT USE!
-08.0 92 49.86 1709 3036 30267 3655 91.5 1.756 !DANGEROUS LOAD-DO NOT USE!
-06.0 94 50.95 1749 3178 32458 3743 92.6 1.704 !DANGEROUS LOAD-DO NOT USE!
-04.0 96 52.03 1788 3323 34813 3825 93.7 1.654 !DANGEROUS LOAD-DO NOT USE!
-02.0 98 53.12 1828 3471 37349 3903 94.6 1.607 !DANGEROUS LOAD-DO NOT USE!
+00.0 100 54.20 1867 3621 40081 3975 95.5 1.561 !DANGEROUS LOAD-DO NOT USE!
+02.0 102 55.28 1906 3775 43030 4041 96.3 1.516 !DANGEROUS LOAD-DO NOT USE!
+04.0 104 56.37 1945 3931 46218 4101 97.0 1.474 !DANGEROUS LOAD-DO NOT USE!
+06.0 106 57.45 1984 4090 49670 4155 97.7 1.432 !DANGEROUS LOAD-DO NOT USE!
+08.0 108 58.54 2023 4251 53413 4202 98.2 1.393 !DANGEROUS LOAD-DO NOT USE!
+10.0 110 59.62 2061 4415 57481 4242 98.7 1.354 !DANGEROUS LOAD-DO NOT USE! |
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One of Us
| Mag primer (higher starting pressure): Cartridge : .45-70 Govt. SAAMI
Bullet : .457, 451, LYM LRN GC 457406
Useable Case Capaci: 53.348 grain H2O = 3.464 cm³
Cartridge O.A.L. L6: 2.770 inch = 70.36 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Winchester 748
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 71 37.68 1301 1760 15472 2475 76.3 2.387
-18.0 73 38.62 1334 1851 16426 2574 77.8 2.326
-16.0 75 39.56 1368 1944 17437 2672 79.3 2.266
-14.0 77 40.51 1401 2041 18506 2770 80.7 2.208
-12.0 78 41.45 1435 2140 19644 2866 82.1 2.152
-10.0 80 42.39 1469 2242 20849 2961 83.5 2.096
-08.0 82 43.33 1503 2347 22127 3055 84.8 2.039
-06.0 84 44.27 1537 2455 23483 3146 86.0 1.984
-04.0 85 45.22 1571 2565 24923 3235 87.2 1.931 ! Near Maximum !
-02.0 87 46.16 1605 2677 26456 3322 88.4 1.880 ! Near Maximum !
+00.0 89 47.10 1639 2793 28083 3407 89.5 1.831 !DANGEROUS LOAD-DO NOT USE!
+02.0 91 48.04 1674 2910 29815 3488 90.6 1.783 !DANGEROUS LOAD-DO NOT USE!
+04.0 93 48.98 1708 3031 31658 3567 91.6 1.737 !DANGEROUS LOAD-DO NOT USE!
+06.0 94 49.93 1742 3153 33618 3642 92.5 1.693 !DANGEROUS LOAD-DO NOT USE!
+08.0 96 50.87 1776 3278 35721 3714 93.4 1.650 !DANGEROUS LOAD-DO NOT USE!
+10.0 98 51.81 1810 3406 37960 3782 94.3 1.609 !DANGEROUS LOAD-DO NOT USE! |
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One of Us
| in your86 I don't think I'd worry too much until I got about 5grs heavier. depending on your bullet weight.
748 is one of those powders that works best at or near a full case, it has disappointed me every time I have tried lowering the amount used. |
| Posts: 5002 | Location: soda springs,id | Registered: 02 April 2008 |
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One of Us
| quote: Originally posted by sambarman338: Thanks jpl, which pressure limit did you use? It looks like the 28,000 psi one.
I ran it for 28, and again for 40, and again at 28 with a mag primer. You can see the input conditions and results for the simulations posted above. quote: Originally posted by sambarman338: I have some other primed brass ready to go; do you think I should start lower and pull the 47 and 48-grain loads?
As you can see, it took 54gr to get 40k. So if you think the brass and gun can take 40k, then the 48gr load should be well below that. |
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One of Us
| Thanks Lamar and jpl.
Yes, jpl, I see now that one table goes a fair bit higher. However, they all seem to wave the Dangerous-load flag at or near the 48-grain level. Do you think I should ignore that until I get close to the 40,000 level?
I did use the CCI magnum primers but I'm afraid that unless I get well beyond my comfort zone, it's hard to see any benefit, though you seem to have used the 28,000psi value for its calculation. While it does pull slightly ahead on velocity/powder yield at the end of the table, I'm not sure it ever does on pressure.
Since I will have done the initial testing with the magnum primers, I might as well press on with them but don't expect to get far.
As to whether my rifle and cases can take it, well, both are near new and have not shown any alarming pressure signs so far. The only incipient problem might be that the ejector seems to engrave a crescent on the lower side of primers. Whether that indicates pressure and a potential weakness I can't say yet but will try to pluck some out in case it happens at ejection. |
| Posts: 5161 | Location: Melbourne, Australia | Registered: 31 March 2009 |
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One of Us
| quote: Originally posted by sambarman338: ...they all seem to wave the Dangerous-load flag...
That is quickload pointing out that the pressure is approaching the limit set in the case specification. Apparently the SAAMI spec for that round is 28ksi. That seems like a pretty low number to me, but I don't know much about old black powder stuff. |
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