Load Specifications
Load data in caliber 7.21 Firebird with .284 | 150gr | Berger Classic Hybrid Hunter bullet and 50 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% | 57,899 psi | 87% | 3084 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 54,679 psi | 82% | 3133 fps | 98.4% |
| Accurate MAGPRO | <<locked>> | 82% | 57,232 psi | 86% | 3205 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 82% | 58,436 psi | 88% | 3176 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 57,566 psi | 86% | 3199 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 57,609 psi | 86% | 3186 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 58,697 psi | 88% | 3327 fps | 99.6% |
| ADI AR 2225 | <<locked>> | 94% | 57,522 psi | 86% | 3205 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 58,073 psi | 87% | 3166 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 58,117 psi | 87% | 3189 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 60,249 psi | 90% | 3140 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 57,711 psi | 87% | 3173 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 56,536 psi | 85% | 3225 fps | 99% |
| Alliant Reloder-50 | <<locked>> | 96% | 57,058 psi | 86% | 3222 fps | 98.8% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 57,580 psi | 86% | 3153 fps | 99.2% |
| Bofors RP15 | <<locked>> | 86% | 57,682 psi | 86% | 3182 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 57,479 psi | 86% | 3199 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 58,117 psi | 87% | 3189 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 58,827 psi | 88% | 3202 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 59,930 psi | 90% | 3186 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 58,784 psi | 88% | 3169 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 57,479 psi | 86% | 3271 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,130 psi | 57% | 2064 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 59,625 psi | 89% | 3156 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 56,391 psi | 85% | 3186 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 58,421 psi | 88% | 3110 fps | 96.8% |
| IMR 8133 Enduron | <<locked>> | 98% | 60,336 psi | 90% | 3251 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 59,959 psi | 90% | 3114 fps | 100% |
| Norma 217 | <<locked>> | 96% | 58,247 psi | 87% | 3215 fps | 100% |
| Norma MRP | <<locked>> | 82% | 58,494 psi | 88% | 3205 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 57,914 psi | 87% | 3209 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 56,434 psi | 85% | 3127 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,073 psi | 59% | 2110 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 58,581 psi | 88% | 3251 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 57,725 psi | 87% | 3228 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 82% | 58,552 psi | 88% | 3143 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 58,117 psi | 87% | 3159 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 56,188 psi | 84% | 3140 fps | 98.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 57,740 psi | 87% | 3153 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 60,162 psi | 90% | 3133 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 58,189 psi | 87% | 3120 fps | 100% |
| Vihtavuori N165 | <<locked>> | 86% | 58,566 psi | 88% | 3110 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 58,218 psi | 87% | 3150 fps | 98.1% |
| Vihtavuori N555 | <<locked>> | 82% | 58,030 psi | 87% | 3117 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 57,653 psi | 86% | 3212 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 59,379 psi | 89% | 3212 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 57,827 psi | 87% | 3228 fps | 99.8% |
| Vihtavuori N570 | <<locked>> | 92% | 59,625 psi | 89% | 3304 fps | 99.1% |
| Winchester StaBALL HD | <<locked>> | 84% | 58,131 psi | 87% | 3186 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 58,218 psi | 87% | 3120 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% | 50,546 psi | 76% | 2969 fps | 100% |
| Accurate 8700 | <<locked>> | 94% | 43,555 psi | 65% | 2923 fps | 95.6% |
| Accurate MAGPRO | <<locked>> | 80% | 53,301 psi | 80% | 3136 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 80% | 54,737 psi | 82% | 3117 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 50,053 psi | 75% | 3068 fps | 99.7% |
| ADI AR 2217 | <<locked>> | 80% | 37,536 psi | 56% | 2795 fps | 97.7% |
| ADI AR 2218 | 97.5 gr | 88% | 43,323 psi | 65% | 3015 fps | 96.2% |
| ADI AR 2225 | <<locked>> | 80% | 34,954 psi | 52% | 2769 fps | 99.3% |
| Alliant Reloder-19 | <<locked>> | 80% | 54,375 psi | 82% | 3104 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 50,792 psi | 76% | 3068 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 49,501 psi | 74% | 2979 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 43,743 psi | 66% | 2936 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 84% | 41,829 psi | 63% | 2930 fps | 95.4% |
| Alliant Reloder-50 | <<locked>> | 88% | 42,264 psi | 63% | 2930 fps | 95% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 47,398 psi | 71% | 2966 fps | 97.5% |
| Bofors RP15 | <<locked>> | 80% | 47,282 psi | 71% | 2999 fps | 99.8% |
| Bofors RP30 | <<locked>> | 80% | 40,814 psi | 61% | 2877 fps | 98.5% |
| Bofors RP5 | <<locked>> | 80% | 50,792 psi | 76% | 3068 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 40,915 psi | 61% | 2877 fps | 99% |
| Hodgdon H4831 | <<locked>> | 80% | 52,359 psi | 78% | 3061 fps | 99.6% |
| Hodgdon H4831 SC | <<locked>> | 80% | 51,343 psi | 77% | 3041 fps | 99.5% |
| Hodgdon Retumbo | 83.7 gr | 80% | 42,989 psi | 64% | 3009 fps | 99.9% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,558 psi | 43% | 1847 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 52,547 psi | 79% | 3038 fps | 99.7% |
| IMR 7828 SSC | <<locked>> | 80% | 48,936 psi | 73% | 3051 fps | 99.6% |
| IMR 7977 Enduron | <<locked>> | 86% | 51,372 psi | 77% | 2986 fps | 95.2% |
| IMR 8133 Enduron | <<locked>> | 80% | 32,489 psi | 49% | 2680 fps | 95.4% |
| Lovex S071 | <<locked>> | 80% | 43,627 psi | 65% | 2844 fps | 100% |
| Norma 217 | <<locked>> | 80% | 33,098 psi | 50% | 2710 fps | 97.9% |
| Norma MRP | <<locked>> | 80% | 54,462 psi | 82% | 3140 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 49,908 psi | 75% | 3071 fps | 99.8% |
| Ramshot Magnum | <<locked>> | 80% | 45,049 psi | 68% | 2933 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,457 psi | 44% | 1893 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 42,917 psi | 64% | 2982 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 39,436 psi | 59% | 2864 fps | 96.8% |
| Rottweil R 904 | <<locked>> | 80% | 54,969 psi | 82% | 3084 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 80% | 54,317 psi | 81% | 3097 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 94% | 45,614 psi | 68% | 2943 fps | 95.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 53,954 psi | 81% | 3094 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 56,289 psi | 84% | 3071 fps | 99.9% |
| Somchem S385 | <<locked>> | 80% | 54,505 psi | 82% | 3061 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 47,950 psi | 72% | 2936 fps | 100% |
| Vihtavuori N170 | <<locked>> | 84% | 47,485 psi | 71% | 2953 fps | 95.7% |
| Vihtavuori N555 | <<locked>> | 80% | 54,462 psi | 82% | 3064 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 53,751 psi | 81% | 3143 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 80% | 45,252 psi | 68% | 2956 fps | 98.9% |
| Vihtavuori N568 | <<locked>> | 80% | 40,335 psi | 60% | 2884 fps | 96.5% |
| Vihtavuori N570 | 91.2 gr | 84% | 44,599 psi | 67% | 3015 fps | 95.9% |
| Winchester StaBALL HD | <<locked>> | 80% | 50,009 psi | 75% | 3061 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 50,647 psi | 76% | 2995 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 50 powders for 7.21 Firebird loaded with the .284 | 150gr | Berger Classic Hybrid Hunter. ADI AR 2218 delivers the highest muzzle velocity at 3,327 fps; across all powders the maximum-charge window runs from 2,064 fps to 3,327 fps. Accurate 8700 gives the best case fill at 100 %, and 50 of the 50 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 150.0 gr projectile in 0.284" calls for a 1:11.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, Hodgdon TrailBoss, ReloadSwiss RS 14 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 | 150gr | Berger Classic Hybrid Hunter 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.