Load Specifications
Load data in caliber 7.21 Firebird with .284 | 184gr | Berger F-Open Hybrid Target bullet and 42 powders. The key underlying parameters are shown in the table above.
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.
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Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 82% | 59,350 psi | 89% | 2841 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 57,087 psi | 86% | 2936 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 82% | 59,088 psi | 89% | 2956 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 59,596 psi | 89% | 2953 fps | 100% |
| ADI AR 2218 | <<locked>> | 92% | 56,695 psi | 85% | 3048 fps | 100% |
| ADI AR 2225 | <<locked>> | 92% | 60,234 psi | 90% | 2976 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 59,640 psi | 89% | 2946 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 82% | 58,189 psi | 87% | 2841 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 59,756 psi | 90% | 2930 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 58,929 psi | 88% | 3018 fps | 100% |
| Alliant Reloder-50 | <<locked>> | 94% | 59,727 psi | 90% | 3025 fps | 99.9% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 58,697 psi | 88% | 2923 fps | 100% |
| Bofors RP15 | <<locked>> | 84% | 59,234 psi | 89% | 2940 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 59,611 psi | 89% | 2966 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 59,640 psi | 89% | 2946 fps | 100% |
| Hodgdon H1000 | <<locked>> | 86% | 56,884 psi | 85% | 2910 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 59,944 psi | 90% | 2927 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 60,336 psi | 90% | 3035 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,319 psi | 57% | 1870 fps | 100% |
| Hodgdon US 869 | <<locked>> | 96% | 57,334 psi | 86% | 2940 fps | 97.1% |
| IMR 7828 SSC | <<locked>> | 82% | 58,001 psi | 87% | 2946 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 59,466 psi | 89% | 2887 fps | 98.6% |
| IMR 8133 Enduron | <<locked>> | 94% | 58,871 psi | 88% | 2972 fps | 100% |
| Lovex D100 | <<locked>> | 90% | 57,682 psi | 86% | 2894 fps | 97.6% |
| Lovex S071 | <<locked>> | 86% | 57,972 psi | 87% | 2822 fps | 100% |
| Norma 217 | <<locked>> | 92% | 57,014 psi | 85% | 2936 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 59,988 psi | 90% | 2969 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 60,060 psi | 90% | 3038 fps | 97.8% |
| Ramshot Magnum | <<locked>> | 84% | 58,363 psi | 87% | 2894 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,523 psi | 59% | 1913 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 84% | 56,826 psi | 85% | 2959 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 59,901 psi | 90% | 3005 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 57,682 psi | 86% | 2894 fps | 97.6% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 58,218 psi | 87% | 2936 fps | 99.6% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 55,680 psi | 83% | 2920 fps | 98.5% |
| Vihtavuori 24N41 | <<locked>> | 94% | 57,667 psi | 86% | 2943 fps | 97.1% |
| Vihtavuori N165 | <<locked>> | 84% | 59,741 psi | 90% | 2867 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 59,582 psi | 89% | 2930 fps | 99.5% |
| Vihtavuori N565 | <<locked>> | 84% | 57,305 psi | 86% | 2923 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 60,017 psi | 90% | 3005 fps | 100% |
| Vihtavuori N570 | <<locked>> | 88% | 57,783 psi | 87% | 3022 fps | 99.8% |
| Winchester Supreme 780 | <<locked>> | 82% | 59,277 psi | 89% | 2877 fps | 100% |
Start Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 80% | 55,521 psi | 83% | 2792 fps | 100% |
| Accurate 8700 | <<locked>> | 86% | 36,753 psi | 55% | 2559 fps | 95.3% |
| ADI AR 2213 | <<locked>> | 80% | 55,172 psi | 83% | 2897 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 42,061 psi | 63% | 2667 fps | 99.8% |
| ADI AR 2218 | <<locked>> | 80% | 36,172 psi | 54% | 2625 fps | 95.7% |
| ADI AR 2225 | <<locked>> | 80% | 39,508 psi | 59% | 2648 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 55,840 psi | 84% | 2890 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 54,433 psi | 82% | 2789 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 48,733 psi | 73% | 2769 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 80% | 40,712 psi | 61% | 2687 fps | 97.2% |
| Alliant Reloder-50 | <<locked>> | 82% | 38,522 psi | 58% | 2628 fps | 95.9% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 51,532 psi | 77% | 2808 fps | 99.5% |
| Bofors RP15 | <<locked>> | 80% | 52,112 psi | 78% | 2831 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 45,672 psi | 68% | 2743 fps | 100% |
| Bofors RP5 | <<locked>> | 80% | 55,840 psi | 84% | 2890 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 45,832 psi | 69% | 2736 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 80% | 56,086 psi | 84% | 2871 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 48,718 psi | 73% | 2861 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,819 psi | 43% | 1670 fps | 100% |
| Hodgdon US 869 | <<locked>> | 92% | 49,705 psi | 75% | 2808 fps | 95.3% |
| IMR 7828 SSC | <<locked>> | 80% | 54,157 psi | 81% | 2887 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 80% | 45,905 psi | 69% | 2657 fps | 95.9% |
| IMR 8133 Enduron | <<locked>> | 80% | 36,767 psi | 55% | 2575 fps | 98.9% |
| Lovex D100 | <<locked>> | 84% | 46,702 psi | 70% | 2707 fps | 95% |
| Lovex S071 | <<locked>> | 80% | 48,095 psi | 72% | 2680 fps | 100% |
| Norma 217 | <<locked>> | 80% | 37,797 psi | 57% | 2602 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 55,695 psi | 83% | 2910 fps | 100% |
| Ramshot LRT | <<locked>> | 88% | 48,573 psi | 73% | 2841 fps | 95.1% |
| Ramshot Magnum | <<locked>> | 80% | 50,401 psi | 76% | 2782 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,820 psi | 45% | 1716 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 48,762 psi | 73% | 2838 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 44,585 psi | 67% | 2753 fps | 99.5% |
| Shooters World 50 BMG | <<locked>> | 84% | 46,702 psi | 70% | 2707 fps | 95% |
| SNPE Vectan SP 13 | <<locked>> | 86% | 38,841 psi | 58% | 2582 fps | 95.7% |
| Vihtavuori 20N29 | <<locked>> | 92% | 41,930 psi | 63% | 2667 fps | 95.1% |
| Vihtavuori 24N41 | <<locked>> | 90% | 50,024 psi | 75% | 2815 fps | 95.3% |
| Vihtavuori N165 | <<locked>> | 80% | 52,591 psi | 79% | 2766 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 45,556 psi | 68% | 2694 fps | 97.2% |
| Vihtavuori N565 | <<locked>> | 80% | 50,067 psi | 75% | 2805 fps | 100% |
| Vihtavuori N568 | <<locked>> | 80% | 45,339 psi | 68% | 2762 fps | 99.3% |
| Vihtavuori N570 | <<locked>> | 80% | 43,410 psi | 65% | 2759 fps | 97.6% |
| Winchester Supreme 780 | <<locked>> | 80% | 55,477 psi | 83% | 2822 fps | 100% |
ᴾ possible press load - work up slowly to this load while watching for signs of excessive pressure.
This overview compares 42 powders for 7.21 Firebird loaded with the .284 | 184gr | Berger F-Open Hybrid Target. ADI AR 2218 delivers the highest muzzle velocity at 3,048 fps; across all powders the maximum-charge window runs from 1,870 fps to 3,048 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 42 of the 42 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (460 MPa), the top charges use 57–90 %, leaving at least 10 % headroom. The 184.0 gr projectile in 0.284" calls for a 1:9.0 twist; slower twists will usually not stabilise this weight. Hodgdon TrailBoss, ReloadSwiss RS 14, Vihtavuori 20N29 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. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.