Load Specifications
Load data in caliber 7.21 Firebird with .284 | 140gr | Sellier & Bellot FMJ 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, 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% | 59,756 psi | 90% | 3196 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 52,156 psi | 78% | 3163 fps | 97.3% |
| Accurate MAGPRO | <<locked>> | 84% | 59,205 psi | 89% | 3320 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 82% | 56,521 psi | 85% | 3232 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 59,596 psi | 89% | 3314 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 59,219 psi | 89% | 3294 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 56,130 psi | 84% | 3360 fps | 98.9% |
| ADI AR 2225 | <<locked>> | 96% | 59,001 psi | 88% | 3314 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 60,002 psi | 90% | 3281 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 60,089 psi | 90% | 3307 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 58,117 psi | 87% | 3199 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 59,277 psi | 89% | 3284 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 59,292 psi | 89% | 3294 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 58,378 psi | 88% | 3337 fps | 98.9% |
| Alliant Reloder-50 | <<locked>> | 98% | 58,726 psi | 88% | 3327 fps | 98.6% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 59,582 psi | 89% | 3264 fps | 99.1% |
| Bofors RP15 | <<locked>> | 88% | 59,437 psi | 89% | 3294 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 59,190 psi | 89% | 3307 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 60,089 psi | 90% | 3307 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 56,521 psi | 85% | 3248 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 57,943 psi | 87% | 3235 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 84% | 56,840 psi | 85% | 3219 fps | 99.7% |
| Hodgdon Retumbo | <<locked>> | 90% | 59,074 psi | 89% | 3386 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,927 psi | 57% | 2129 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 57,870 psi | 87% | 3212 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 86% | 58,146 psi | 87% | 3297 fps | 100% |
| IMR 8133 Enduron | <<locked>> | 98% | 57,957 psi | 87% | 3301 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 58,059 psi | 87% | 3173 fps | 100% |
| Norma 217 | <<locked>> | 98% | 59,466 psi | 89% | 3320 fps | 100% |
| Norma MRP | <<locked>> | 82% | 56,260 psi | 84% | 3258 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 59,814 psi | 90% | 3323 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 58,378 psi | 88% | 3238 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,986 psi | 58% | 2175 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 55,869 psi | 84% | 3297 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 59,538 psi | 89% | 3340 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 82% | 56,840 psi | 85% | 3199 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 84% | 59,886 psi | 90% | 3274 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 53,911 psi | 81% | 3176 fps | 97.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 59,553 psi | 89% | 3268 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 58,291 psi | 87% | 3186 fps | 99.8% |
| Somchem S385 | <<locked>> | 84% | 60,089 psi | 90% | 3235 fps | 100% |
| Vihtavuori N165 | <<locked>> | 86% | 56,608 psi | 85% | 3166 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 60,176 psi | 90% | 3258 fps | 97.9% |
| Vihtavuori N555 | <<locked>> | 84% | 59,886 psi | 90% | 3232 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 59,538 psi | 89% | 3327 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 88% | 57,232 psi | 86% | 3258 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 92% | 59,509 psi | 89% | 3340 fps | 99.7% |
| Vihtavuori N570 | <<locked>> | 92% | 57,058 psi | 86% | 3340 fps | 98.3% |
| Winchester StaBALL HD | <<locked>> | 86% | 59,727 psi | 90% | 3301 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 60,336 psi | 90% | 3235 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% | 48,820 psi | 73% | 3022 fps | 100% |
| Accurate 8700 | <<locked>> | 96% | 44,817 psi | 67% | 3018 fps | 95.2% |
| Accurate MAGPRO | <<locked>> | 80% | 51,242 psi | 77% | 3179 fps | 98.9% |
| ADI AR 2209 | <<locked>> | 80% | 52,808 psi | 79% | 3166 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 48,211 psi | 72% | 3114 fps | 99.1% |
| ADI AR 2217 | <<locked>> | 80% | 36,027 psi | 54% | 2828 fps | 96.4% |
| ADI AR 2218 | 100.8 gr | 90% | 44,759 psi | 67% | 3117 fps | 95.8% |
| ADI AR 2225 | <<locked>> | 80% | 33,330 psi | 50% | 2795 fps | 98.3% |
| Alliant Reloder-19 | <<locked>> | 80% | 52,649 psi | 79% | 3159 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 48,979 psi | 73% | 3114 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 47,718 psi | 72% | 3035 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 41,814 psi | 63% | 2979 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 55,143 psi | 83% | 3232 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 86% | 43,091 psi | 65% | 3031 fps | 95.1% |
| Alliant Reloder-50 | <<locked>> | 92% | 46,833 psi | 70% | 3100 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 45,847 psi | 69% | 3012 fps | 96.4% |
| Bofors RP15 | <<locked>> | 80% | 45,600 psi | 68% | 3045 fps | 99.3% |
| Bofors RP30 | <<locked>> | 80% | 39,117 psi | 59% | 2913 fps | 97.5% |
| Bofors RP5 | <<locked>> | 80% | 48,979 psi | 73% | 3114 fps | 99.8% |
| Hodgdon H1000 | <<locked>> | 80% | 39,247 psi | 59% | 2913 fps | 98.1% |
| Hodgdon H4831 | <<locked>> | 80% | 50,444 psi | 76% | 3107 fps | 99.1% |
| Hodgdon H4831 SC | <<locked>> | 80% | 49,632 psi | 74% | 3087 fps | 98.9% |
| Hodgdon Retumbo | 84.5 gr | 80% | 40,872 psi | 61% | 3041 fps | 99.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,471 psi | 43% | 1909 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 50,879 psi | 76% | 3091 fps | 99.2% |
| IMR 7828 SSC | <<locked>> | 80% | 46,934 psi | 70% | 3094 fps | 98.9% |
| IMR 8133 Enduron | <<locked>> | 84% | 35,708 psi | 54% | 2838 fps | 96.1% |
| Lovex S071 | <<locked>> | 80% | 42,003 psi | 63% | 2890 fps | 99.9% |
| Norma 217 | <<locked>> | 80% | 31,357 psi | 47% | 2733 fps | 96.4% |
| Norma MRP | <<locked>> | 80% | 52,402 psi | 79% | 3192 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 47,805 psi | 72% | 3114 fps | 99.3% |
| Ramshot Magnum | <<locked>> | 80% | 43,120 psi | 65% | 2969 fps | 99.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,327 psi | 44% | 1955 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 40,799 psi | 61% | 3015 fps | 99.8% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 37,536 psi | 56% | 2890 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 53,185 psi | 80% | 3136 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 80% | 52,359 psi | 78% | 3150 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 96% | 46,876 psi | 70% | 3038 fps | 95.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 52,011 psi | 78% | 3143 fps | 99.9% |
| Somchem S361 | <<locked>> | 80% | 54,563 psi | 82% | 3123 fps | 99.5% |
| Somchem S385 | <<locked>> | 80% | 52,750 psi | 79% | 3117 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 46,340 psi | 69% | 2986 fps | 99.7% |
| Vihtavuori N170 | <<locked>> | 86% | 48,979 psi | 73% | 3054 fps | 95.4% |
| Vihtavuori N555 | <<locked>> | 80% | 52,460 psi | 79% | 3117 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 51,764 psi | 78% | 3192 fps | 99.3% |
| Vihtavuori N565 | <<locked>> | 80% | 43,453 psi | 65% | 2992 fps | 98% |
| Vihtavuori N568 | <<locked>> | 80% | 38,537 psi | 58% | 2913 fps | 95% |
| Vihtavuori N570 | 94.3 gr | 86% | 45,774 psi | 69% | 3117 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 80% | 47,645 psi | 71% | 3114 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 48,936 psi | 73% | 3048 fps | 99.8% |
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 | 140gr | Sellier & Bellot FMJ. Hodgdon Retumbo delivers the highest muzzle velocity at 3,386 fps; across all powders the maximum-charge window runs from 2,129 fps to 3,386 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 140.0 gr projectile in 0.284" calls for a 1:12.5 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, Vihtavuori N570, Hodgdon Retumbo rank at the top here: for 7.21 Firebird with the .284 | 140gr | Sellier & Bellot FMJ 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.