Load Specifications
Load data in caliber 7.21 Firebird with .284 | 160gr | Barnes Solid bullet and 53 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2218, Hodgdon Retumbo and Vihtavuori N570.
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>> | 84% | 58,001 psi | 87% | 3002 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 54,636 psi | 82% | 3061 fps | 98.7% |
| Accurate MAGPRO | <<locked>> | 82% | 57,348 psi | 86% | 3127 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 82% | 58,755 psi | 88% | 3094 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 57,740 psi | 87% | 3117 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 57,624 psi | 86% | 3104 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 58,740 psi | 88% | 3251 fps | 99.8% |
| ADI AR 2225 | <<locked>> | 94% | 57,624 psi | 86% | 3127 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 58,218 psi | 87% | 3084 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 58,305 psi | 87% | 3110 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 56,695 psi | 85% | 3005 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 57,870 psi | 87% | 3091 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 56,536 psi | 85% | 3150 fps | 99.3% |
| Alliant Reloder-50 | <<locked>> | 96% | 57,116 psi | 86% | 3150 fps | 99.1% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 57,740 psi | 87% | 3077 fps | 99.5% |
| Bofors RP15 | <<locked>> | 86% | 57,899 psi | 87% | 3104 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 57,624 psi | 86% | 3120 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 58,305 psi | 87% | 3110 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 59,059 psi | 89% | 3120 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 60,147 psi | 90% | 3104 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 58,958 psi | 88% | 3087 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 57,769 psi | 87% | 3192 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,087 psi | 57% | 1991 fps | 100% |
| Hodgdon US 869ᴾ | <<locked>> | 100% | 59,495 psi | 89% | 3130 fps | 96.1% |
| IMR 4955 Enduron | <<locked>> | 84% | 59,872 psi | 90% | 3077 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 56,521 psi | 85% | 3104 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 58,682 psi | 88% | 3035 fps | 97.3% |
| IMR 8133 Enduron | <<locked>> | 96% | 56,695 psi | 85% | 3117 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 60,133 psi | 90% | 3031 fps | 100% |
| Norma 217 | <<locked>> | 96% | 58,305 psi | 87% | 3136 fps | 100% |
| Norma MRP | <<locked>> | 82% | 58,697 psi | 88% | 3123 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 58,262 psi | 87% | 3130 fps | 100% |
| Ramshot LRT | <<locked>> | 96% | 58,088 psi | 87% | 3169 fps | 96% |
| Ramshot Magnum | <<locked>> | 86% | 56,608 psi | 85% | 3051 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,233 psi | 59% | 2037 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 58,711 psi | 88% | 3173 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 57,798 psi | 87% | 3153 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 58,827 psi | 88% | 3061 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 58,233 psi | 87% | 3077 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 56,202 psi | 84% | 3068 fps | 98.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 57,870 psi | 87% | 3074 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 60,278 psi | 90% | 3051 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 58,407 psi | 88% | 3038 fps | 100% |
| Vihtavuori 24N41 | <<locked>> | 98% | 60,249 psi | 90% | 3143 fps | 96.2% |
| Vihtavuori N165 | <<locked>> | 86% | 58,639 psi | 88% | 3028 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 58,436 psi | 88% | 3074 fps | 98.5% |
| Vihtavuori N555 | <<locked>> | 82% | 58,291 psi | 87% | 3035 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 57,899 psi | 87% | 3133 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 59,524 psi | 89% | 3133 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 57,856 psi | 87% | 3150 fps | 99.9% |
| Vihtavuori N570 | <<locked>> | 92% | 59,625 psi | 89% | 3225 fps | 99.4% |
| Winchester StaBALL HD | <<locked>> | 84% | 58,479 psi | 88% | 3107 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 58,465 psi | 88% | 3041 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 80% | 50,734 psi | 76% | 2894 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 40,495 psi | 61% | 2789 fps | 95.1% |
| Accurate MAGPRO | <<locked>> | 80% | 53,490 psi | 80% | 3061 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 80% | 54,940 psi | 82% | 3035 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 50,314 psi | 75% | 2995 fps | 99.8% |
| ADI AR 2217 | <<locked>> | 80% | 37,797 psi | 57% | 2733 fps | 98.2% |
| ADI AR 2218 | 91.6 gr | 86% | 40,306 psi | 60% | 2871 fps | 95.5% |
| ADI AR 2225 | <<locked>> | 80% | 35,157 psi | 53% | 2707 fps | 99.6% |
| Alliant Reloder-19 | <<locked>> | 80% | 54,563 psi | 82% | 3025 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 51,053 psi | 77% | 2992 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 49,763 psi | 75% | 2904 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 43,947 psi | 66% | 2864 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 84% | 42,018 psi | 63% | 2871 fps | 96.1% |
| Alliant Reloder-50 | <<locked>> | 88% | 42,351 psi | 63% | 2867 fps | 95.6% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 47,500 psi | 71% | 2894 fps | 97.9% |
| Bofors RP15 | <<locked>> | 80% | 47,601 psi | 71% | 2927 fps | 99.9% |
| Bofors RP30 | <<locked>> | 80% | 41,002 psi | 61% | 2812 fps | 98.9% |
| Bofors RP5 | <<locked>> | 80% | 51,053 psi | 77% | 2992 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 41,162 psi | 62% | 2812 fps | 99.4% |
| Hodgdon H4831 | <<locked>> | 80% | 52,475 psi | 79% | 2982 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 80% | 51,561 psi | 77% | 2966 fps | 99.7% |
| Hodgdon Retumbo | 80.5 gr | 80% | 43,221 psi | 65% | 2940 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,689 psi | 43% | 1785 fps | 100% |
| Hodgdon US 869 | <<locked>> | 98% | 55,303 psi | 83% | 3061 fps | 95.1% |
| IMR 4955 Enduron | <<locked>> | 80% | 52,678 psi | 79% | 2959 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 80% | 49,182 psi | 74% | 2979 fps | 99.8% |
| IMR 7977 Enduron | <<locked>> | 86% | 51,517 psi | 77% | 2913 fps | 95.7% |
| IMR 8133 Enduron | <<locked>> | 80% | 32,706 psi | 49% | 2625 fps | 96.2% |
| Lovex S071 | <<locked>> | 80% | 43,903 psi | 66% | 2772 fps | 100% |
| Norma 217 | <<locked>> | 80% | 33,257 psi | 50% | 2651 fps | 98.4% |
| Norma MRP | <<locked>> | 80% | 54,708 psi | 82% | 3061 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 50,154 psi | 75% | 2999 fps | 99.9% |
| Ramshot LRT | <<locked>> | 94% | 54,099 psi | 81% | 3100 fps | 95% |
| Ramshot Magnum | <<locked>> | 80% | 45,339 psi | 68% | 2864 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,486 psi | 44% | 1827 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 43,018 psi | 64% | 2913 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 39,581 psi | 59% | 2805 fps | 97.4% |
| Rottweil R 904 | <<locked>> | 80% | 55,100 psi | 83% | 3005 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 54,491 psi | 82% | 3018 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 42,612 psi | 64% | 2815 fps | 95.4% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 54,157 psi | 81% | 3015 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 56,463 psi | 85% | 2995 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 54,737 psi | 82% | 2986 fps | 100% |
| Vihtavuori 24N41 | <<locked>> | 96% | 56,057 psi | 84% | 3074 fps | 95.2% |
| Vihtavuori N165 | <<locked>> | 80% | 48,153 psi | 72% | 2864 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 44,483 psi | 67% | 2818 fps | 95.4% |
| Vihtavuori N555 | <<locked>> | 80% | 54,766 psi | 82% | 2982 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 53,983 psi | 81% | 3071 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 80% | 45,411 psi | 68% | 2887 fps | 99.2% |
| Vihtavuori N568 | <<locked>> | 80% | 40,422 psi | 61% | 2818 fps | 97.1% |
| Vihtavuori N570 | 85.6 gr | 82% | 41,597 psi | 62% | 2877 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 80% | 50,270 psi | 75% | 2986 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 50,937 psi | 76% | 2923 fps | 100% |
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 53 powders for 7.21 Firebird loaded with the .284 | 160gr | Barnes Solid. ADI AR 2218 delivers the highest muzzle velocity at 3,251 fps; across all powders the maximum-charge window runs from 1,991 fps to 3,251 fps. Accurate 8700 gives the best case fill at 100 %, and 53 of the 53 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 160.0 gr projectile in 0.284" calls for a 1:9.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, Hodgdon TrailBoss, Hodgdon US 869 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. ADI AR 2218, Hodgdon Retumbo, Vihtavuori N570 rank at the top here: for 7.21 Firebird with the .284 | 160gr | Barnes Solid 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.