Load Specifications
Load data in caliber 7.21 Firebird with .284 | 140gr | Rhino Solid Shank 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% | 59,582 psi | 89% | 3196 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 51,866 psi | 78% | 3159 fps | 97.3% |
| Accurate MAGPRO | <<locked>> | 84% | 58,813 psi | 88% | 3317 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 84% | 60,307 psi | 90% | 3291 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 59,248 psi | 89% | 3310 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 59,016 psi | 88% | 3291 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 60,234 psi | 90% | 3432 fps | 99.4% |
| ADI AR 2225 | <<locked>> | 96% | 58,813 psi | 88% | 3310 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 59,843 psi | 90% | 3278 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 59,712 psi | 90% | 3301 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 57,943 psi | 87% | 3199 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 58,929 psi | 88% | 3278 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 59,103 psi | 89% | 3291 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 58,030 psi | 87% | 3330 fps | 98.8% |
| Alliant Reloder-50 | <<locked>> | 98% | 58,407 psi | 88% | 3323 fps | 98.5% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 59,451 psi | 89% | 3261 fps | 99.1% |
| Bofors RP15 | <<locked>> | 88% | 59,263 psi | 89% | 3291 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 58,842 psi | 88% | 3304 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 59,712 psi | 90% | 3301 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 56,362 psi | 84% | 3248 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 57,769 psi | 87% | 3235 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 84% | 56,666 psi | 85% | 3215 fps | 99.7% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 60,336 psi | 90% | 3179 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 58,871 psi | 88% | 3383 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,956 psi | 57% | 2126 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 57,725 psi | 87% | 3209 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 86% | 57,740 psi | 87% | 3291 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 92% | 60,292 psi | 90% | 3215 fps | 96.5% |
| IMR 8133 Enduron | <<locked>> | 98% | 57,624 psi | 86% | 3294 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 57,696 psi | 86% | 3166 fps | 100% |
| Norma 217 | <<locked>> | 98% | 59,277 psi | 89% | 3317 fps | 100% |
| Norma MRP | <<locked>> | 84% | 60,220 psi | 90% | 3320 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 59,625 psi | 89% | 3320 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 58,204 psi | 87% | 3238 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,015 psi | 58% | 2175 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 60,060 psi | 90% | 3363 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 59,176 psi | 89% | 3333 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 84% | 60,321 psi | 90% | 3255 fps | 100% |
| Rottweil R 905 | <<locked>> | 84% | 59,712 psi | 90% | 3271 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 53,621 psi | 80% | 3169 fps | 97.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 59,335 psi | 89% | 3268 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 58,146 psi | 87% | 3182 fps | 99.8% |
| Somchem S385 | <<locked>> | 84% | 59,930 psi | 90% | 3232 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 60,307 psi | 90% | 3222 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 59,843 psi | 90% | 3251 fps | 97.9% |
| Vihtavuori N555 | <<locked>> | 84% | 59,495 psi | 89% | 3228 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 59,393 psi | 89% | 3327 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 88% | 57,058 psi | 86% | 3255 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 92% | 59,364 psi | 89% | 3337 fps | 99.7% |
| Vihtavuori N570 | <<locked>> | 92% | 56,666 psi | 85% | 3337 fps | 98.3% |
| Winchester StaBALL HD | <<locked>> | 86% | 59,538 psi | 89% | 3297 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 60,017 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% | 48,646 psi | 73% | 3018 fps | 100% |
| Accurate 8700 | <<locked>> | 96% | 44,527 psi | 67% | 3012 fps | 95.1% |
| Accurate MAGPRO | <<locked>> | 80% | 51,082 psi | 77% | 3176 fps | 98.8% |
| ADI AR 2209 | <<locked>> | 80% | 52,620 psi | 79% | 3166 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 48,022 psi | 72% | 3107 fps | 99.1% |
| ADI AR 2217 | <<locked>> | 80% | 35,882 psi | 54% | 2825 fps | 96.3% |
| ADI AR 2218 | 100.4 gr | 90% | 44,498 psi | 67% | 3110 fps | 95.7% |
| ADI AR 2225 | <<locked>> | 80% | 33,185 psi | 50% | 2792 fps | 98.2% |
| Alliant Reloder-19 | <<locked>> | 80% | 52,460 psi | 79% | 3153 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 48,805 psi | 73% | 3110 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 47,529 psi | 71% | 3031 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 41,626 psi | 62% | 2976 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 54,926 psi | 82% | 3228 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 86% | 42,801 psi | 64% | 3025 fps | 95% |
| Alliant Reloder-50 | <<locked>> | 92% | 46,528 psi | 70% | 3094 fps | 95.7% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 45,556 psi | 68% | 3005 fps | 96.3% |
| Bofors RP15 | <<locked>> | 80% | 45,426 psi | 68% | 3041 fps | 99.3% |
| Bofors RP30 | <<locked>> | 80% | 38,943 psi | 58% | 2910 fps | 97.4% |
| Bofors RP5 | <<locked>> | 80% | 48,805 psi | 73% | 3110 fps | 99.7% |
| Hodgdon H1000 | <<locked>> | 80% | 39,088 psi | 59% | 2910 fps | 98.1% |
| Hodgdon H4831 | <<locked>> | 80% | 50,285 psi | 75% | 3104 fps | 99% |
| Hodgdon H4831 SC | <<locked>> | 80% | 49,472 psi | 74% | 3087 fps | 98.9% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 56,405 psi | 85% | 3123 fps | 100% |
| Hodgdon Retumbo | 84.2 gr | 80% | 40,683 psi | 61% | 3038 fps | 99.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,471 psi | 43% | 1909 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 50,720 psi | 76% | 3087 fps | 99.2% |
| IMR 7828 SSC | <<locked>> | 80% | 46,746 psi | 70% | 3091 fps | 98.9% |
| IMR 7977 Enduron | <<locked>> | 90% | 56,463 psi | 85% | 3150 fps | 95.7% |
| IMR 8133 Enduron | <<locked>> | 84% | 35,549 psi | 53% | 2835 fps | 96% |
| Lovex S071 | <<locked>> | 80% | 41,814 psi | 63% | 2887 fps | 99.9% |
| Norma 217 | <<locked>> | 80% | 31,183 psi | 47% | 2726 fps | 96.3% |
| Norma MRP | <<locked>> | 80% | 52,185 psi | 78% | 3189 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 47,572 psi | 71% | 3110 fps | 99.3% |
| Ramshot Magnum | <<locked>> | 80% | 42,960 psi | 64% | 2969 fps | 99.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,327 psi | 44% | 1955 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 40,466 psi | 61% | 3009 fps | 99.8% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 37,362 psi | 56% | 2887 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 53,011 psi | 79% | 3133 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 80% | 52,170 psi | 78% | 3143 fps | 99.9% |
| SNPE Vectan SP 13 | <<locked>> | 96% | 46,615 psi | 70% | 3035 fps | 95.4% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 51,822 psi | 78% | 3143 fps | 99.9% |
| Somchem S361 | <<locked>> | 80% | 54,244 psi | 81% | 3117 fps | 99.5% |
| Somchem S385 | <<locked>> | 80% | 52,576 psi | 79% | 3114 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 46,166 psi | 69% | 2982 fps | 99.7% |
| Vihtavuori N170 | <<locked>> | 86% | 48,849 psi | 73% | 3051 fps | 95.4% |
| Vihtavuori N555 | <<locked>> | 80% | 52,243 psi | 78% | 3117 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 51,547 psi | 77% | 3186 fps | 99.3% |
| Vihtavuori N565 | <<locked>> | 80% | 43,294 psi | 65% | 2992 fps | 97.9% |
| Vihtavuori N568 | <<locked>> | 80% | 38,348 psi | 57% | 2910 fps | 95% |
| Vihtavuori N570 | 94 gr | 86% | 45,600 psi | 68% | 3114 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 80% | 47,369 psi | 71% | 3107 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 48,776 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 59 powders for 7.21 Firebird loaded with the .284 | 140gr | Rhino Solid Shank. ADI AR 2218 delivers the highest muzzle velocity at 3,432 fps; across all powders the maximum-charge window runs from 2,126 fps to 3,432 fps. Accurate 8700 gives the best case fill at 100 %, and 59 of the 59 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, 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, Vihtavuori N570, Hodgdon Retumbo rank at the top here: for 7.21 Firebird with the .284 | 140gr | Rhino Solid Shank they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon 50BMG, Hodgdon US 869, Vihtavuori 20N29 burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.