Load Specifications
Load data in caliber 7.21 Firebird with .284 | 140gr | Prvi Partizan PSP BT bullet and 52 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2218, Vihtavuori N570 and Hodgdon Retumbo.
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>> | 86% | 59,393 psi | 89% | 3192 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 51,895 psi | 78% | 3159 fps | 97.3% |
| Accurate MAGPRO | <<locked>> | 84% | 58,842 psi | 88% | 3317 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 84% | 60,292 psi | 90% | 3291 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 59,219 psi | 89% | 3310 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 59,045 psi | 89% | 3294 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 60,263 psi | 90% | 3435 fps | 99.4% |
| ADI AR 2225 | <<locked>> | 96% | 58,842 psi | 88% | 3314 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 59,872 psi | 90% | 3278 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 59,741 psi | 90% | 3301 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 57,943 psi | 87% | 3199 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 58,914 psi | 88% | 3278 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 59,103 psi | 89% | 3291 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 58,059 psi | 87% | 3333 fps | 98.8% |
| Alliant Reloder-50 | <<locked>> | 98% | 58,392 psi | 88% | 3323 fps | 98.5% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 59,292 psi | 89% | 3261 fps | 99.1% |
| Bofors RP15 | <<locked>> | 88% | 59,088 psi | 89% | 3291 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 58,813 psi | 88% | 3304 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 59,741 psi | 90% | 3301 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 56,333 psi | 84% | 3248 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 57,798 psi | 87% | 3235 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 84% | 56,695 psi | 85% | 3215 fps | 99.7% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 60,350 psi | 90% | 3179 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 58,639 psi | 88% | 3379 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,971 psi | 57% | 2126 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 57,711 psi | 87% | 3209 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 86% | 57,769 psi | 87% | 3294 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 92% | 60,321 psi | 90% | 3215 fps | 96.5% |
| IMR 8133 Enduron | <<locked>> | 98% | 57,595 psi | 86% | 3294 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 57,725 psi | 87% | 3166 fps | 100% |
| Norma 217 | <<locked>> | 98% | 59,088 psi | 89% | 3317 fps | 100% |
| Norma MRP | <<locked>> | 84% | 60,234 psi | 90% | 3320 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 59,611 psi | 89% | 3320 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 58,030 psi | 87% | 3235 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,015 psi | 58% | 2175 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 60,089 psi | 90% | 3363 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 59,205 psi | 89% | 3333 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 84% | 60,321 psi | 90% | 3255 fps | 100% |
| Rottweil R 905 | <<locked>> | 84% | 59,741 psi | 90% | 3271 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 53,650 psi | 80% | 3173 fps | 97.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 59,350 psi | 89% | 3268 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 58,160 psi | 87% | 3182 fps | 99.8% |
| Somchem S385 | <<locked>> | 84% | 59,930 psi | 90% | 3232 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 60,089 psi | 90% | 3215 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 59,872 psi | 90% | 3255 fps | 97.9% |
| Vihtavuori N555 | <<locked>> | 84% | 59,524 psi | 89% | 3228 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 59,393 psi | 89% | 3327 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 88% | 56,884 psi | 85% | 3255 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 92% | 59,176 psi | 89% | 3333 fps | 99.7% |
| Vihtavuori N570 | <<locked>> | 92% | 56,695 psi | 85% | 3337 fps | 98.3% |
| Winchester StaBALL HD | <<locked>> | 86% | 59,524 psi | 89% | 3297 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 59,988 psi | 90% | 3232 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% | 48,631 psi | 73% | 3018 fps | 100% |
| Accurate 8700 | <<locked>> | 96% | 44,556 psi | 67% | 3012 fps | 95.1% |
| Accurate MAGPRO | <<locked>> | 80% | 50,923 psi | 76% | 3176 fps | 98.8% |
| ADI AR 2209 | <<locked>> | 80% | 52,634 psi | 79% | 3163 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 48,022 psi | 72% | 3110 fps | 99.1% |
| ADI AR 2217 | <<locked>> | 80% | 35,897 psi | 54% | 2825 fps | 96.3% |
| ADI AR 2218 | 100.4 gr | 90% | 44,483 psi | 67% | 3110 fps | 95.7% |
| ADI AR 2225 | <<locked>> | 80% | 33,199 psi | 50% | 2792 fps | 98.3% |
| Alliant Reloder-19 | <<locked>> | 80% | 52,489 psi | 79% | 3156 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 48,776 psi | 73% | 3110 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 47,369 psi | 71% | 3028 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 41,626 psi | 62% | 2976 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 54,752 psi | 82% | 3225 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 86% | 42,830 psi | 64% | 3028 fps | 95% |
| Alliant Reloder-50 | <<locked>> | 92% | 46,543 psi | 70% | 3094 fps | 95.7% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 45,571 psi | 68% | 3005 fps | 96.3% |
| Bofors RP15 | <<locked>> | 80% | 45,426 psi | 68% | 3045 fps | 99.3% |
| Bofors RP30 | <<locked>> | 80% | 38,957 psi | 58% | 2910 fps | 97.4% |
| Bofors RP5 | <<locked>> | 80% | 48,776 psi | 73% | 3110 fps | 99.7% |
| Hodgdon H1000 | <<locked>> | 80% | 39,117 psi | 59% | 2910 fps | 98% |
| Hodgdon H4831 | <<locked>> | 80% | 50,314 psi | 75% | 3104 fps | 99% |
| Hodgdon H4831 SC | <<locked>> | 80% | 49,487 psi | 74% | 3087 fps | 98.9% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 56,434 psi | 85% | 3127 fps | 100% |
| Hodgdon Retumbo | 84.2 gr | 80% | 40,712 psi | 61% | 3035 fps | 99.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,471 psi | 43% | 1909 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 50,705 psi | 76% | 3087 fps | 99.2% |
| IMR 7828 SSC | <<locked>> | 80% | 46,746 psi | 70% | 3091 fps | 98.9% |
| IMR 7977 Enduron | <<locked>> | 90% | 56,449 psi | 85% | 3150 fps | 95.7% |
| IMR 8133 Enduron | <<locked>> | 84% | 35,418 psi | 53% | 2831 fps | 95.9% |
| Lovex S071 | <<locked>> | 80% | 41,829 psi | 63% | 2887 fps | 99.9% |
| Norma 217 | <<locked>> | 80% | 31,183 psi | 47% | 2730 fps | 96.3% |
| Norma MRP | <<locked>> | 80% | 52,199 psi | 78% | 3186 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 47,601 psi | 71% | 3110 fps | 99.3% |
| Ramshot Magnum | <<locked>> | 80% | 42,960 psi | 64% | 2966 fps | 99.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,327 psi | 44% | 1955 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 40,451 psi | 61% | 3009 fps | 99.8% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 37,376 psi | 56% | 2887 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 53,040 psi | 80% | 3136 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 80% | 52,185 psi | 78% | 3146 fps | 99.9% |
| SNPE Vectan SP 13 | <<locked>> | 96% | 46,601 psi | 70% | 3035 fps | 95.4% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 51,837 psi | 78% | 3143 fps | 99.9% |
| Somchem S361 | <<locked>> | 80% | 54,273 psi | 81% | 3120 fps | 99.5% |
| Somchem S385 | <<locked>> | 80% | 52,576 psi | 79% | 3114 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 46,195 psi | 69% | 2982 fps | 99.7% |
| Vihtavuori N170 | <<locked>> | 86% | 48,878 psi | 73% | 3054 fps | 95.4% |
| Vihtavuori N555 | <<locked>> | 80% | 52,228 psi | 78% | 3117 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 51,576 psi | 77% | 3189 fps | 99.3% |
| Vihtavuori N565 | <<locked>> | 80% | 43,149 psi | 65% | 2989 fps | 97.9% |
| Vihtavuori N568 | <<locked>> | 82% | 41,292 psi | 62% | 2979 fps | 96.1% |
| Vihtavuori N570 | 94 gr | 86% | 45,600 psi | 68% | 3114 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 80% | 47,413 psi | 71% | 3107 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 48,747 psi | 73% | 3045 fps | 99.7% |
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 52 powders for 7.21 Firebird loaded with the .284 | 140gr | Prvi Partizan PSP BT. ADI AR 2218 delivers the highest muzzle velocity at 3,435 fps; across all powders the maximum-charge window runs from 2,126 fps to 3,435 fps. Accurate 8700 gives the best case fill at 100 %, and 52 of the 52 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 140.0 gr projectile in 0.284" calls for a 1:12.0 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, Vihtavuori N570, Hodgdon Retumbo rank at the top here: for 7.21 Firebird with the .284 | 140gr | Prvi Partizan PSP BT 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.