Load Specifications
Load data in caliber 7.21 Firebird with .284 | 140gr | Barnes Solid bullet and 52 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, ADI AR 2218 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>> | 86% | 57,885 psi | 87% | 3169 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 49,748 psi | 75% | 3123 fps | 96.6% |
| Accurate MAGPRO | <<locked>> | 84% | 57,174 psi | 86% | 3291 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 84% | 58,769 psi | 88% | 3268 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 57,725 psi | 87% | 3287 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 94% | 57,014 psi | 85% | 3264 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 58,088 psi | 87% | 3399 fps | 99.1% |
| ADI AR 2225 | <<locked>> | 96% | 56,579 psi | 85% | 3287 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 58,378 psi | 88% | 3258 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 58,218 psi | 87% | 3281 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 60,147 psi | 90% | 3232 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 57,145 psi | 86% | 3255 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 57,203 psi | 86% | 3268 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 60,205 psi | 90% | 3369 fps | 99% |
| Alliant Reloder-50 | <<locked>> | 98% | 56,057 psi | 84% | 3287 fps | 98% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 57,856 psi | 87% | 3238 fps | 98.8% |
| Bofors RP15 | <<locked>> | 88% | 57,595 psi | 86% | 3268 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 56,971 psi | 85% | 3278 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 58,218 psi | 87% | 3281 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 58,479 psi | 88% | 3284 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 60,176 psi | 90% | 3274 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 86% | 59,205 psi | 89% | 3258 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 58,842 psi | 88% | 3159 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 56,695 psi | 85% | 3356 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,869 psi | 57% | 2116 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 60,017 psi | 90% | 3245 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 88% | 60,133 psi | 90% | 3330 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 92% | 58,827 psi | 88% | 3189 fps | 96% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 59,553 psi | 89% | 3330 fps | 100% |
| Lovex S071 | <<locked>> | 92% | 59,843 psi | 90% | 3199 fps | 100% |
| Norma 217 | <<locked>> | 98% | 57,000 psi | 85% | 3291 fps | 100% |
| Norma MRP | <<locked>> | 84% | 58,465 psi | 88% | 3297 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 57,769 psi | 87% | 3294 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 56,202 psi | 84% | 3212 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,928 psi | 58% | 2169 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 57,885 psi | 87% | 3340 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 57,087 psi | 86% | 3304 fps | 99.7% |
| Rottweil R 904 | <<locked>> | 84% | 58,856 psi | 88% | 3232 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 84% | 58,146 psi | 87% | 3245 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 51,750 psi | 78% | 3136 fps | 96.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 57,769 psi | 87% | 3245 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 56,753 psi | 85% | 3159 fps | 99.7% |
| Somchem S385 | <<locked>> | 84% | 58,494 psi | 88% | 3212 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 58,537 psi | 88% | 3196 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 58,204 psi | 87% | 3225 fps | 97.5% |
| Vihtavuori N555 | <<locked>> | 84% | 58,059 psi | 87% | 3209 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 57,711 psi | 87% | 3301 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 90% | 59,205 psi | 89% | 3294 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 92% | 57,246 psi | 86% | 3304 fps | 99.4% |
| Vihtavuori N570 | <<locked>> | 94% | 58,769 psi | 88% | 3376 fps | 98.5% |
| Winchester StaBALL HD | <<locked>> | 86% | 57,435 psi | 86% | 3274 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 58,421 psi | 88% | 3209 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% | 47,282 psi | 71% | 2999 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 46,195 psi | 69% | 3051 fps | 95.6% |
| Accurate MAGPRO | <<locked>> | 80% | 49,443 psi | 74% | 3150 fps | 98.5% |
| ADI AR 2209 | <<locked>> | 80% | 51,271 psi | 77% | 3143 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 80% | 46,673 psi | 70% | 3084 fps | 98.8% |
| ADI AR 2217 | <<locked>> | 80% | 34,795 psi | 52% | 2799 fps | 95.7% |
| ADI AR 2218 | 100 gr | 92% | 46,180 psi | 69% | 3153 fps | 96.2% |
| ADI AR 2225 | <<locked>> | 80% | 32,126 psi | 48% | 2762 fps | 97.7% |
| Alliant Reloder-19 | <<locked>> | 80% | 51,155 psi | 77% | 3133 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 47,442 psi | 71% | 3087 fps | 99.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 46,108 psi | 69% | 3012 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 40,248 psi | 60% | 2953 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 53,098 psi | 80% | 3202 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 88% | 44,512 psi | 67% | 3071 fps | 95.5% |
| Alliant Reloder-50 | <<locked>> | 94% | 48,182 psi | 72% | 3133 fps | 96.1% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 44,440 psi | 67% | 2982 fps | 95.9% |
| Bofors RP15 | <<locked>> | 80% | 44,092 psi | 66% | 3018 fps | 99% |
| Bofors RP30 | <<locked>> | 80% | 37,666 psi | 56% | 2884 fps | 96.9% |
| Bofors RP5 | <<locked>> | 80% | 47,442 psi | 71% | 3087 fps | 99.6% |
| Hodgdon H1000 | <<locked>> | 80% | 37,898 psi | 57% | 2884 fps | 97.6% |
| Hodgdon H4831 | <<locked>> | 80% | 49,037 psi | 74% | 3081 fps | 98.7% |
| Hodgdon H4831 SC | <<locked>> | 80% | 48,225 psi | 72% | 3064 fps | 98.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 55,129 psi | 83% | 3107 fps | 100% |
| Hodgdon Retumbo | 82.1 gr | 80% | 39,334 psi | 59% | 3005 fps | 99% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,413 psi | 43% | 1900 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 49,545 psi | 74% | 3064 fps | 98.9% |
| IMR 7828 SSC | <<locked>> | 80% | 45,353 psi | 68% | 3064 fps | 98.6% |
| IMR 7977 Enduron | <<locked>> | 90% | 55,158 psi | 83% | 3127 fps | 95.2% |
| IMR 8133 Enduron | <<locked>> | 84% | 34,214 psi | 51% | 2805 fps | 95.3% |
| Lovex S071 | <<locked>> | 80% | 40,625 psi | 61% | 2864 fps | 99.8% |
| Norma 217 | <<locked>> | 80% | 29,950 psi | 45% | 2697 fps | 95.6% |
| Norma MRP | <<locked>> | 80% | 50,662 psi | 76% | 3166 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 45,992 psi | 69% | 3081 fps | 99% |
| Ramshot Magnum | <<locked>> | 80% | 41,553 psi | 62% | 2943 fps | 99.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,283 psi | 44% | 1946 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 39,044 psi | 59% | 2982 fps | 99.6% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 38,827 psi | 58% | 2930 fps | 95.7% |
| Rottweil R 904 | <<locked>> | 80% | 51,735 psi | 78% | 3110 fps | 99.5% |
| Rottweil R 905 | <<locked>> | 80% | 50,952 psi | 76% | 3127 fps | 99.9% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 48,196 psi | 72% | 3071 fps | 95.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 50,604 psi | 76% | 3120 fps | 99.8% |
| Somchem S361 | <<locked>> | 80% | 52,997 psi | 79% | 3097 fps | 99.3% |
| Somchem S385 | <<locked>> | 80% | 51,300 psi | 77% | 3094 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 44,947 psi | 67% | 2959 fps | 99.5% |
| Vihtavuori N170 | <<locked>> | 88% | 50,720 psi | 76% | 3091 fps | 95.8% |
| Vihtavuori N555 | <<locked>> | 80% | 50,923 psi | 76% | 3097 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 50,053 psi | 75% | 3163 fps | 99% |
| Vihtavuori N565 | <<locked>> | 80% | 41,916 psi | 63% | 2963 fps | 97.5% |
| Vihtavuori N568 | <<locked>> | 82% | 39,798 psi | 60% | 2949 fps | 95.5% |
| Vihtavuori N570 | 93.7 gr | 88% | 47,195 psi | 71% | 3153 fps | 95.9% |
| Winchester StaBALL HD | <<locked>> | 80% | 45,542 psi | 68% | 3084 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 47,384 psi | 71% | 3018 fps | 99.6% |
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 | Barnes Solid. ADI AR 2218 delivers the highest muzzle velocity at 3,399 fps; across all powders the maximum-charge window runs from 2,116 fps to 3,399 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 1:9.5 twist; slower twists will usually not stabilise this weight. Accurate 8700, Hodgdon TrailBoss, IMR 8133 Enduron 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. Hodgdon Retumbo, ADI AR 2218, Vihtavuori N570 rank at the top here: for 7.21 Firebird with the .284 | 140gr | 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.