Load Specifications
Load data in caliber 7.21 Firebird with .284 | 150gr | Nosler Partition 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, 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% | 57,696 psi | 86% | 3081 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 54,331 psi | 81% | 3127 fps | 98.3% |
| Accurate MAGPRO | <<locked>> | 82% | 57,029 psi | 85% | 3202 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 82% | 58,421 psi | 88% | 3173 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 57,566 psi | 86% | 3196 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 57,421 psi | 86% | 3179 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 58,537 psi | 88% | 3323 fps | 99.6% |
| ADI AR 2225 | <<locked>> | 94% | 57,348 psi | 86% | 3202 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 57,899 psi | 87% | 3159 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 58,146 psi | 87% | 3189 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 60,292 psi | 90% | 3140 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 57,537 psi | 86% | 3169 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 56,376 psi | 85% | 3219 fps | 99% |
| Alliant Reloder-50 | <<locked>> | 96% | 56,855 psi | 85% | 3219 fps | 98.7% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 57,624 psi | 86% | 3153 fps | 99.2% |
| Bofors RP15 | <<locked>> | 86% | 57,522 psi | 86% | 3179 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 57,493 psi | 86% | 3196 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 58,146 psi | 87% | 3189 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 58,885 psi | 88% | 3199 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 59,770 psi | 90% | 3179 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 58,813 psi | 88% | 3166 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 57,464 psi | 86% | 3271 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,087 psi | 57% | 2064 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 59,466 psi | 89% | 3153 fps | 100% |
| IMR 7828 SSC | <<locked>> | 86% | 60,263 psi | 90% | 3245 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 58,320 psi | 87% | 3107 fps | 96.8% |
| IMR 8133 Enduron | <<locked>> | 98% | 60,147 psi | 90% | 3248 fps | 100% |
| Lovex D100 | <<locked>> | 94% | 60,307 psi | 90% | 3159 fps | 96.3% |
| Lovex S071 | <<locked>> | 90% | 59,973 psi | 90% | 3114 fps | 100% |
| Norma 217 | <<locked>> | 96% | 58,059 psi | 87% | 3212 fps | 100% |
| Norma MRP | <<locked>> | 82% | 58,276 psi | 87% | 3199 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 57,914 psi | 87% | 3205 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 56,246 psi | 84% | 3123 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,175 psi | 59% | 2110 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 58,421 psi | 88% | 3248 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 57,551 psi | 86% | 3222 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 82% | 58,378 psi | 88% | 3136 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 57,943 psi | 87% | 3156 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 94% | 60,307 psi | 90% | 3159 fps | 96.3% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 56,057 psi | 84% | 3133 fps | 98.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 57,580 psi | 86% | 3150 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 60,017 psi | 90% | 3130 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 58,204 psi | 87% | 3120 fps | 100% |
| Vihtavuori N165 | <<locked>> | 86% | 58,421 psi | 88% | 3107 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 58,073 psi | 87% | 3143 fps | 98.1% |
| Vihtavuori N555 | <<locked>> | 82% | 58,044 psi | 87% | 3117 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 57,508 psi | 86% | 3209 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 59,393 psi | 89% | 3209 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 57,653 psi | 86% | 3225 fps | 99.8% |
| Vihtavuori N570 | <<locked>> | 92% | 59,451 psi | 89% | 3301 fps | 99.1% |
| Winchester StaBALL HD | <<locked>> | 84% | 58,088 psi | 87% | 3182 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 58,044 psi | 87% | 3117 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% | 50,531 psi | 76% | 2969 fps | 100% |
| Accurate 8700 | <<locked>> | 94% | 43,410 psi | 65% | 2917 fps | 95.5% |
| Accurate MAGPRO | <<locked>> | 80% | 53,156 psi | 80% | 3133 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 80% | 54,578 psi | 82% | 3114 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 50,024 psi | 75% | 3064 fps | 99.7% |
| ADI AR 2217 | <<locked>> | 80% | 37,507 psi | 56% | 2795 fps | 97.7% |
| ADI AR 2218 | 97.3 gr | 88% | 43,178 psi | 65% | 3009 fps | 96.1% |
| ADI AR 2225 | <<locked>> | 80% | 34,824 psi | 52% | 2766 fps | 99.3% |
| Alliant Reloder-19 | <<locked>> | 80% | 54,375 psi | 82% | 3104 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 50,778 psi | 76% | 3064 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 49,472 psi | 74% | 2979 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 43,584 psi | 65% | 2933 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 84% | 41,698 psi | 63% | 2927 fps | 95.4% |
| Alliant Reloder-50 | <<locked>> | 90% | 45,484 psi | 68% | 2999 fps | 96.1% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 47,253 psi | 71% | 2963 fps | 97.4% |
| Bofors RP15 | <<locked>> | 80% | 47,282 psi | 71% | 2999 fps | 99.8% |
| Bofors RP30 | <<locked>> | 80% | 40,799 psi | 61% | 2877 fps | 98.5% |
| Bofors RP5 | <<locked>> | 80% | 50,778 psi | 76% | 3064 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 40,930 psi | 61% | 2877 fps | 99% |
| Hodgdon H4831 | <<locked>> | 80% | 52,214 psi | 78% | 3054 fps | 99.6% |
| Hodgdon H4831 SC | <<locked>> | 80% | 51,343 psi | 77% | 3041 fps | 99.5% |
| Hodgdon Retumbo | 83.5 gr | 80% | 42,801 psi | 64% | 3002 fps | 99.9% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,631 psi | 43% | 1850 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 52,402 psi | 79% | 3035 fps | 99.7% |
| IMR 7828 SSC | <<locked>> | 80% | 48,776 psi | 73% | 3048 fps | 99.5% |
| IMR 7977 Enduron | <<locked>> | 86% | 51,213 psi | 77% | 2982 fps | 95.1% |
| IMR 8133 Enduron | <<locked>> | 80% | 32,460 psi | 49% | 2677 fps | 95.3% |
| Lovex D100 | <<locked>> | 92% | 56,217 psi | 84% | 3094 fps | 95.3% |
| Lovex S071 | <<locked>> | 80% | 43,627 psi | 65% | 2844 fps | 100% |
| Norma 217 | <<locked>> | 80% | 32,967 psi | 49% | 2707 fps | 97.8% |
| Norma MRP | <<locked>> | 80% | 54,447 psi | 82% | 3136 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 49,893 psi | 75% | 3071 fps | 99.8% |
| Ramshot Magnum | <<locked>> | 80% | 45,034 psi | 68% | 2930 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,385 psi | 44% | 1893 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 42,757 psi | 64% | 2979 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 39,305 psi | 59% | 2861 fps | 96.7% |
| Rottweil R 904 | <<locked>> | 80% | 54,810 psi | 82% | 3081 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 80% | 54,143 psi | 81% | 3094 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 56,217 psi | 84% | 3094 fps | 95.3% |
| SNPE Vectan SP 13 | <<locked>> | 94% | 45,484 psi | 68% | 2936 fps | 95.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 53,795 psi | 81% | 3091 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 56,144 psi | 84% | 3068 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% | 47,369 psi | 71% | 2949 fps | 95.7% |
| Vihtavuori N555 | <<locked>> | 80% | 54,288 psi | 81% | 3061 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 53,737 psi | 81% | 3143 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 80% | 45,092 psi | 68% | 2953 fps | 98.8% |
| Vihtavuori N568 | <<locked>> | 80% | 40,176 psi | 60% | 2881 fps | 96.4% |
| Vihtavuori N570 | 91 gr | 84% | 44,440 psi | 67% | 3009 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 80% | 49,995 psi | 75% | 3064 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 50,633 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 52 powders for 7.21 Firebird loaded with the .284 | 150gr | Nosler Partition. ADI AR 2218 delivers the highest muzzle velocity at 3,323 fps; across all powders the maximum-charge window runs from 2,064 fps to 3,323 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 150.0 gr projectile in 0.284" calls for a 1:11.5 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 | Nosler Partition 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.