Load Specifications
Load data in caliber .284 Win. with .284 | 139gr | Sellier & Bellot SPRN bullet and 97 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Power Pro 2000-MR, Hodgdon Superformance and ReloadSwiss RS 60.
Important Notice: DO NOT go below Minimum Charge or above Maximum Charge. Since we have no control over the equipment and components used, any responsibility and liability for the results achieved is rejected.
Only powders/loads that match the current filter criteria are displayed: max pressure of a load ≤ 90% of max. standardized pressure, fill rate ≥ 80% and propellant combustion ≥ 95%. Use the sliders above the tables to adjust these thresholds.
Charge: Powder weight in grains. Start with the minimum load and work up carefully.
FR (Fill Rate): Case fill as a percentage. Values above 100% mean compressed loads.
MaxP / %: Maximum chamber pressure in bar and as a percentage of the standardized maximum for this caliber.
V(0): Muzzle velocity in feet per second (fps) at the standardized barrel length.
z (Powder Burn): Estimated propellant combustion percentage at bullet exit.
A valid access license is required to use the Personalized Load Calculator.
You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 84% | 56,782 psi | 89% | 2802 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 55,883 psi | 88% | 2831 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 57,435 psi | 90% | 2897 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 54,636 psi | 86% | 2828 fps | 97% |
| Accurate 3100ᴾ | <<locked>> | 100% | 42,844 psi | 67% | 2723 fps | 96.4% |
| Accurate 4064 | <<locked>> | 90% | 55,709 psi | 87% | 2877 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 55,811 psi | 87% | 2969 fps | 99.7% |
| ADI AR 2206H | <<locked>> | 86% | 55,912 psi | 88% | 2910 fps | 100% |
| ADI AR 2208 | <<locked>> | 92% | 56,869 psi | 89% | 2910 fps | 99.9% |
| ADI Benchmark 8208 | <<locked>> | 84% | 54,795 psi | 86% | 2858 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 55,869 psi | 88% | 2831 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 55,564 psi | 87% | 3028 fps | 99.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 92% | 57,232 psi | 90% | 2933 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 90% | 57,696 psi | 90% | 2956 fps | 100% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 56,565 psi | 89% | 3018 fps | 99.9% |
| Alliant Reloder-17 | <<locked>> | 94% | 54,433 psi | 85% | 3005 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 40,770 psi | 64% | 2756 fps | 99.1% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 45,774 psi | 72% | 2923 fps | 98.5% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 55,811 psi | 87% | 2927 fps | 99.8% |
| Bofors RP3 | <<locked>> | 90% | 54,143 psi | 85% | 2894 fps | 100% |
| Bofors RP7 | <<locked>> | 96% | 57,696 psi | 90% | 2920 fps | 97.8% |
| Hodgdon Benchmark | <<locked>> | 84% | 56,420 psi | 88% | 2841 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 54,259 psi | 85% | 2887 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 56,449 psi | 88% | 2992 fps | 99.9% |
| Hodgdon H380 | <<locked>> | 90% | 55,259 psi | 87% | 2910 fps | 99.4% |
| Hodgdon H414 | <<locked>> | 96% | 54,984 psi | 86% | 2963 fps | 98% |
| Hodgdon H4350 | <<locked>> | 94% | 55,230 psi | 87% | 2920 fps | 96.8% |
| Hodgdon H4895 | <<locked>> | 86% | 56,463 psi | 88% | 2920 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 53,055 psi | 83% | 2894 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 88% | 55,927 psi | 88% | 2949 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 55,463 psi | 87% | 2999 fps | 97.7% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,752 psi | 56% | 1775 fps | 100% |
| Hodgdon VARGET | <<locked>> | 88% | 57,551 psi | 90% | 2920 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 56,608 psi | 89% | 2900 fps | 100% |
| IMR 4064 | <<locked>> | 90% | 56,289 psi | 88% | 2890 fps | 99.9% |
| IMR 4166 Enduron | <<locked>> | 88% | 56,391 psi | 88% | 2874 fps | 98.1% |
| IMR 4350 | <<locked>> | 98% | 54,607 psi | 86% | 2890 fps | 97.3% |
| IMR 4451 Enduron | <<locked>> | 94% | 56,188 psi | 88% | 2900 fps | 98% |
| IMR 4831ᴾ | <<locked>> | 100% | 56,130 psi | 88% | 2953 fps | 99.8% |
| IMR 4895 | <<locked>> | 88% | 55,550 psi | 87% | 2933 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 54,795 psi | 86% | 2858 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 55,724 psi | 87% | 2884 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 55,230 psi | 87% | 2835 fps | 100% |
| Lovex S062 | <<locked>> | 90% | 56,434 psi | 88% | 2890 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 55,463 psi | 87% | 2890 fps | 99% |
| Lovex S070 | <<locked>> | 98% | 56,608 psi | 89% | 2927 fps | 98.4% |
| Norma 201 | <<locked>> | 86% | 54,708 psi | 86% | 2854 fps | 100% |
| Norma 202 | <<locked>> | 86% | 55,085 psi | 86% | 2854 fps | 100% |
| Norma 203B | <<locked>> | 90% | 56,855 psi | 89% | 2943 fps | 100% |
| Norma 204 | <<locked>> | 98% | 55,143 psi | 86% | 2940 fps | 96.2% |
| Norma URP | <<locked>> | 98% | 54,636 psi | 86% | 2953 fps | 99.6% |
| Ramshot Big Game | <<locked>> | 90% | 57,609 psi | 90% | 2969 fps | 100% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 57,232 psi | 90% | 3005 fps | 99% |
| Ramshot TAC | <<locked>> | 84% | 55,027 psi | 86% | 2877 fps | 99% |
| Ramshot Wild Boar | <<locked>> | 84% | 54,897 psi | 86% | 2897 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 82% | 55,477 psi | 87% | 2858 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,114 psi | 57% | 1818 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 55,419 psi | 87% | 2890 fps | 98.5% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 54,491 psi | 85% | 2966 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 54,317 psi | 85% | 3005 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 55,259 psi | 87% | 2986 fps | 99.6% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 54,940 psi | 86% | 3015 fps | 99.5% |
| Rottweil R 901 | <<locked>> | 84% | 55,593 psi | 87% | 2835 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 55,274 psi | 87% | 2854 fps | 100% |
| Rottweil R 903 | <<locked>> | 94% | 57,696 psi | 90% | 2940 fps | 100% |
| Rottweil R 907 | <<locked>> | 96% | 57,696 psi | 90% | 2920 fps | 97.8% |
| Shooters World Long Rifle | <<locked>> | 96% | 55,463 psi | 87% | 2890 fps | 99% |
| Shooters World Match Rifle | <<locked>> | 86% | 55,724 psi | 87% | 2884 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 56,434 psi | 88% | 2890 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 56,608 psi | 89% | 2927 fps | 98.4% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 55,767 psi | 87% | 2949 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 86% | 57,217 psi | 90% | 2910 fps | 99.5% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 54,230 psi | 85% | 2877 fps | 99.9% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 55,912 psi | 88% | 2789 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 56,507 psi | 89% | 2792 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 55,883 psi | 88% | 2844 fps | 98% |
| Somchem S321 | <<locked>> | 82% | 55,985 psi | 88% | 2890 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 55,506 psi | 87% | 2789 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 56,942 psi | 89% | 2900 fps | 100% |
| Somchem S355 | <<locked>> | 92% | 54,433 psi | 85% | 2887 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 52,736 psi | 83% | 2953 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 49,023 psi | 77% | 2835 fps | 96.2% |
| Vihtavuori N130 | <<locked>> | 82% | 55,796 psi | 87% | 2753 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 56,173 psi | 88% | 2772 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 55,100 psi | 86% | 2818 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 55,854 psi | 88% | 2835 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 55,796 psi | 87% | 2864 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 57,276 psi | 90% | 2949 fps | 99.7% |
| Vihtavuori N530 | <<locked>> | 84% | 55,303 psi | 87% | 2858 fps | 100% |
| Vihtavuori N540 | <<locked>> | 90% | 57,566 psi | 90% | 2881 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 56,057 psi | 88% | 2953 fps | 99.6% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 44,875 psi | 70% | 2835 fps | 99% |
| Winchester 6.5 StaBALL | <<locked>> | 98% | 57,638 psi | 90% | 2927 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 55,521 psi | 87% | 2907 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 54,984 psi | 86% | 2963 fps | 98% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 36,608 psi | 57% | 2762 fps | 99.1% |
| Winchester StaBALL Match | <<locked>> | 86% | 54,360 psi | 85% | 2890 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 80% | 50,154 psi | 79% | 2710 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 43,062 psi | 67% | 2641 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 50,169 psi | 79% | 2792 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 47,906 psi | 75% | 2717 fps | 95.6% |
| Accurate 3100 | <<locked>> | 98% | 40,001 psi | 63% | 2671 fps | 95.5% |
| Accurate 4064 | <<locked>> | 80% | 40,727 psi | 64% | 2635 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 34,330 psi | 54% | 2562 fps | 95.5% |
| ADI AR 2206H | <<locked>> | 80% | 46,238 psi | 72% | 2749 fps | 99.4% |
| ADI AR 2208 | <<locked>> | 80% | 39,291 psi | 62% | 2595 fps | 97.7% |
| ADI Benchmark 8208 | <<locked>> | 80% | 48,312 psi | 76% | 2756 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 49,037 psi | 77% | 2740 fps | 100% |
| Alliant Power Pro 2000-MR | 46.7 gr | 80% | 42,308 psi | 66% | 2785 fps | 98.3% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 39,102 psi | 61% | 2618 fps | 98.9% |
| Alliant Reloder-15 | <<locked>> | 80% | 41,945 psi | 66% | 2684 fps | 98.4% |
| Alliant Reloder-16 | <<locked>> | 84% | 34,432 psi | 54% | 2575 fps | 95.6% |
| Alliant Reloder-17 | <<locked>> | 80% | 33,910 psi | 53% | 2589 fps | 97.3% |
| Alliant Reloder-23 | <<locked>> | 90% | 29,834 psi | 47% | 2477 fps | 95.3% |
| Alliant Reloder-26 | <<locked>> | 94% | 36,840 psi | 58% | 2720 fps | 95.8% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 45,745 psi | 72% | 2756 fps | 98.7% |
| Bofors RP3 | <<locked>> | 80% | 38,899 psi | 61% | 2625 fps | 99% |
| Bofors RP7 | <<locked>> | 88% | 45,034 psi | 71% | 2703 fps | 95.1% |
| Hodgdon Benchmark | <<locked>> | 80% | 50,125 psi | 79% | 2746 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 47,500 psi | 74% | 2782 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 52,591 psi | 82% | 2933 fps | 99.8% |
| Hodgdon H380 | <<locked>> | 80% | 39,697 psi | 62% | 2628 fps | 96.7% |
| Hodgdon H414 | <<locked>> | 88% | 42,134 psi | 66% | 2730 fps | 95% |
| Hodgdon H4350 | <<locked>> | 90% | 48,675 psi | 76% | 2808 fps | 95.3% |
| Hodgdon H4895 | <<locked>> | 80% | 46,717 psi | 73% | 2759 fps | 99.7% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 29,646 psi | 46% | 2415 fps | 95.5% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 42,917 psi | 67% | 2736 fps | 99.6% |
| Hodgdon Superformance | 54.7 gr | 90% | 44,802 psi | 70% | 2805 fps | 95.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,643 psi | 42% | 1588 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 44,875 psi | 70% | 2713 fps | 99.5% |
| IMR 3031 | <<locked>> | 80% | 46,499 psi | 73% | 2749 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 41,263 psi | 65% | 2631 fps | 98.3% |
| IMR 4166 Enduron | <<locked>> | 80% | 43,685 psi | 68% | 2651 fps | 95.4% |
| IMR 4350 | <<locked>> | 92% | 45,208 psi | 71% | 2730 fps | 95.2% |
| IMR 4451 Enduron | <<locked>> | 86% | 43,845 psi | 69% | 2680 fps | 95.3% |
| IMR 4831 | <<locked>> | 84% | 33,257 psi | 52% | 2520 fps | 95.2% |
| IMR 4895 | <<locked>> | 80% | 42,989 psi | 67% | 2713 fps | 99% |
| IMR 8208 XBR | <<locked>> | 80% | 48,312 psi | 76% | 2756 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 45,832 psi | 72% | 2730 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 46,035 psi | 72% | 2680 fps | 99.4% |
| Lovex S062 | <<locked>> | 80% | 41,278 psi | 65% | 2635 fps | 99.5% |
| Lovex S065 | <<locked>> | 84% | 38,479 psi | 60% | 2575 fps | 95.4% |
| Lovex S070 | <<locked>> | 88% | 41,466 psi | 65% | 2657 fps | 95% |
| Norma 201 | <<locked>> | 80% | 45,455 psi | 71% | 2703 fps | 99.8% |
| Norma 202 | <<locked>> | 80% | 45,716 psi | 72% | 2707 fps | 100% |
| Norma 203B | <<locked>> | 80% | 41,321 psi | 65% | 2671 fps | 98.7% |
| Norma 204 | <<locked>> | 96% | 51,619 psi | 81% | 2881 fps | 95.4% |
| Norma URP | <<locked>> | 84% | 34,563 psi | 54% | 2562 fps | 95.5% |
| Ramshot Big Game | <<locked>> | 80% | 41,075 psi | 64% | 2687 fps | 98.5% |
| Ramshot Hunter | <<locked>> | 90% | 41,089 psi | 64% | 2717 fps | 95.7% |
| Ramshot TAC | <<locked>> | 80% | 48,153 psi | 75% | 2762 fps | 98% |
| Ramshot Wild Boar | <<locked>> | 80% | 47,906 psi | 75% | 2782 fps | 99.5% |
| Ramshot X-Terminator | <<locked>> | 80% | 52,214 psi | 82% | 2808 fps | 99.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,035 psi | 42% | 1627 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 40,016 psi | 63% | 2612 fps | 95% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 44,295 psi | 69% | 2789 fps | 98.8% |
| ReloadSwiss RS 60 | 46 gr | 80% | 36,100 psi | 57% | 2657 fps | 99.7% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 34,069 psi | 53% | 2579 fps | 95% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 36,506 psi | 57% | 2644 fps | 95% |
| Rottweil R 901 | <<locked>> | 80% | 49,284 psi | 77% | 2740 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 43,076 psi | 68% | 2651 fps | 99.6% |
| Rottweil R 903 | <<locked>> | 80% | 36,521 psi | 57% | 2566 fps | 98.2% |
| Rottweil R 907 | <<locked>> | 88% | 45,034 psi | 71% | 2703 fps | 95.1% |
| Shooters World Long Rifle | <<locked>> | 84% | 38,479 psi | 60% | 2575 fps | 95.4% |
| Shooters World Match Rifle | <<locked>> | 80% | 45,832 psi | 72% | 2730 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 41,278 psi | 65% | 2635 fps | 99.5% |
| Shooters World SW4350 | <<locked>> | 88% | 41,466 psi | 65% | 2657 fps | 95% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 37,405 psi | 59% | 2615 fps | 97.7% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 46,688 psi | 73% | 2740 fps | 98.2% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 44,657 psi | 70% | 2713 fps | 99.2% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 46,485 psi | 73% | 2648 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 38,812 psi | 61% | 2513 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 43,076 psi | 68% | 2628 fps | 95.3% |
| Somchem S321 | <<locked>> | 80% | 52,620 psi | 82% | 2838 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 46,340 psi | 73% | 2651 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 46,543 psi | 73% | 2736 fps | 99.4% |
| Somchem S355 | <<locked>> | 80% | 37,449 psi | 59% | 2575 fps | 98.3% |
| Somchem S365 | <<locked>> | 80% | 27,224 psi | 43% | 2402 fps | 95.9% |
| Somchem S385 | <<locked>> | 98% | 45,934 psi | 72% | 2779 fps | 95.4% |
| Vihtavuori N130 | <<locked>> | 80% | 52,359 psi | 82% | 2707 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 46,847 psi | 73% | 2641 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 42,699 psi | 67% | 2631 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 43,192 psi | 68% | 2638 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 35,447 psi | 56% | 2507 fps | 98.9% |
| Vihtavuori N160 | <<locked>> | 82% | 33,779 psi | 53% | 2510 fps | 95% |
| Vihtavuori N530 | <<locked>> | 80% | 48,573 psi | 76% | 2753 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 41,814 psi | 66% | 2631 fps | 100% |
| Vihtavuori N550 | <<locked>> | 84% | 35,578 psi | 56% | 2566 fps | 95.5% |
| Vihtavuori N555 | <<locked>> | 90% | 32,198 psi | 50% | 2552 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 31,531 psi | 49% | 2434 fps | 96.5% |
| Winchester 748 | <<locked>> | 80% | 48,486 psi | 76% | 2802 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 42,134 psi | 66% | 2730 fps | 95% |
| Winchester StaBALL HD | <<locked>> | 94% | 30,110 psi | 47% | 2562 fps | 96% |
| Winchester StaBALL Match | <<locked>> | 80% | 44,353 psi | 70% | 2723 fps | 99.5% |
Recommended = one of the top powders for this cartridge and bullet combination.
ᴾ possible press load - work up slowly to this load while watching for signs of excessive pressure.
This overview compares 97 powders for .284 Win. loaded with the .284 | 139gr | Sellier & Bellot SPRN. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,028 fps; across all powders the maximum-charge window runs from 1,775 fps to 3,028 fps. Accurate 3100 gives the best case fill at 100 %, and 97 of the 97 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 56–90 %, leaving at least 10 % headroom. The 139.0 gr projectile in 0.284" calls for a 1:15.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-16, Alliant Reloder-23 reach 100 % fill or more at maximum charge, so these are compressed loads: they need a long drop tube to seat cleanly and react sensitively to the case capacity of your own brass lot. Alliant Power Pro 2000-MR, Hodgdon Superformance, ReloadSwiss RS 60 rank at the top here: for .284 Win. with the .284 | 139gr | Sellier & Bellot SPRN they combine a high case fill with complete burn and sit in the upper velocity band. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.