Load Specifications
Load data in caliber 7.21 Firebird with .284 | 140gr | Remington PSP 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, 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% | 56,898 psi | 85% | 3153 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 53,606 psi | 80% | 3186 fps | 97.7% |
| Accurate MAGPRO | <<locked>> | 84% | 60,350 psi | 90% | 3340 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 82% | 57,566 psi | 86% | 3245 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 56,652 psi | 85% | 3268 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 92% | 56,478 psi | 85% | 3248 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 57,696 psi | 86% | 3386 fps | 99.2% |
| ADI AR 2225 | <<locked>> | 94% | 56,550 psi | 85% | 3274 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 57,232 psi | 86% | 3235 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 57,232 psi | 86% | 3261 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 59,393 psi | 89% | 3215 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 56,623 psi | 85% | 3241 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 59,959 psi | 90% | 3356 fps | 99.1% |
| Alliant Reloder-50 | <<locked>> | 96% | 56,130 psi | 84% | 3278 fps | 98.2% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 56,884 psi | 85% | 3219 fps | 98.8% |
| Bofors RP15 | <<locked>> | 86% | 56,797 psi | 85% | 3251 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 56,652 psi | 85% | 3264 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 57,232 psi | 86% | 3261 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 57,914 psi | 87% | 3271 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 59,059 psi | 89% | 3255 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 84% | 57,972 psi | 87% | 3238 fps | 99.8% |
| Hodgdon Retumbo | <<locked>> | 88% | 56,333 psi | 84% | 3340 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,029 psi | 57% | 2136 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 58,929 psi | 88% | 3228 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 86% | 59,393 psi | 89% | 3317 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 57,682 psi | 86% | 3173 fps | 96.1% |
| IMR 8133 Enduron | <<locked>> | 98% | 59,466 psi | 89% | 3320 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 59,059 psi | 89% | 3186 fps | 100% |
| Norma 217 | <<locked>> | 96% | 57,014 psi | 85% | 3278 fps | 100% |
| Norma MRP | <<locked>> | 82% | 57,522 psi | 86% | 3274 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 56,956 psi | 85% | 3278 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 59,930 psi | 90% | 3258 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,073 psi | 59% | 2185 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 57,522 psi | 86% | 3320 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 56,608 psi | 85% | 3287 fps | 99.7% |
| Rottweil R 904 | <<locked>> | 82% | 57,783 psi | 87% | 3215 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 57,087 psi | 86% | 3228 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 55,332 psi | 83% | 3199 fps | 97.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 56,724 psi | 85% | 3225 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 59,248 psi | 89% | 3202 fps | 99.9% |
| Somchem S385 | <<locked>> | 82% | 57,464 psi | 86% | 3196 fps | 100% |
| Vihtavuori N165 | <<locked>> | 86% | 57,711 psi | 87% | 3179 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 57,479 psi | 86% | 3212 fps | 97.6% |
| Vihtavuori N555 | <<locked>> | 82% | 57,203 psi | 86% | 3192 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 56,724 psi | 85% | 3278 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 88% | 58,494 psi | 88% | 3278 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 56,869 psi | 85% | 3291 fps | 99.5% |
| Vihtavuori N570 | <<locked>> | 92% | 58,581 psi | 88% | 3363 fps | 98.6% |
| Winchester StaBALL HD | <<locked>> | 84% | 57,087 psi | 86% | 3255 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 57,348 psi | 86% | 3189 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% | 49,821 psi | 75% | 3038 fps | 100% |
| Accurate 8700 | <<locked>> | 96% | 46,195 psi | 69% | 3045 fps | 95.8% |
| Accurate MAGPRO | <<locked>> | 80% | 52,431 psi | 79% | 3199 fps | 99.1% |
| ADI AR 2209 | <<locked>> | 80% | 53,882 psi | 81% | 3186 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 49,255 psi | 74% | 3130 fps | 99.3% |
| ADI AR 2217 | <<locked>> | 80% | 36,782 psi | 55% | 2844 fps | 96.8% |
| ADI AR 2218 | 100.4 gr | 88% | 42,627 psi | 64% | 3061 fps | 95% |
| ADI AR 2225 | <<locked>> | 80% | 34,185 psi | 51% | 2815 fps | 98.6% |
| Alliant Reloder-19 | <<locked>> | 80% | 53,650 psi | 80% | 3173 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 50,009 psi | 75% | 3133 fps | 99.9% |
| Alliant Reloder-23 | <<locked>> | 80% | 48,660 psi | 73% | 3048 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 42,873 psi | 64% | 2999 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 86% | 44,266 psi | 66% | 3054 fps | 95.6% |
| Alliant Reloder-50 | <<locked>> | 90% | 44,672 psi | 67% | 3048 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 46,615 psi | 70% | 3025 fps | 96.7% |
| Bofors RP15 | <<locked>> | 80% | 46,456 psi | 70% | 3061 fps | 99.5% |
| Bofors RP30 | <<locked>> | 80% | 40,103 psi | 60% | 2933 fps | 97.8% |
| Bofors RP5 | <<locked>> | 80% | 50,009 psi | 75% | 3133 fps | 99.9% |
| Hodgdon H1000 | <<locked>> | 80% | 40,190 psi | 60% | 2933 fps | 98.4% |
| Hodgdon H4831 | <<locked>> | 80% | 51,576 psi | 77% | 3127 fps | 99.3% |
| Hodgdon H4831 SC | <<locked>> | 80% | 50,589 psi | 76% | 3107 fps | 99.1% |
| Hodgdon Retumbo | 86.1 gr | 80% | 41,959 psi | 63% | 3061 fps | 99.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,601 psi | 43% | 1919 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 51,779 psi | 78% | 3104 fps | 99.4% |
| IMR 7828 SSC | <<locked>> | 80% | 47,993 psi | 72% | 3114 fps | 99.2% |
| IMR 7977 Enduron | <<locked>> | 88% | 54,056 psi | 81% | 3110 fps | 95.3% |
| IMR 8133 Enduron | <<locked>> | 82% | 34,127 psi | 51% | 2789 fps | 95.4% |
| Lovex S071 | <<locked>> | 80% | 42,859 psi | 64% | 2907 fps | 100% |
| Norma 217 | <<locked>> | 80% | 32,314 psi | 48% | 2753 fps | 96.9% |
| Norma MRP | <<locked>> | 80% | 53,635 psi | 80% | 3212 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 48,892 psi | 73% | 3133 fps | 99.5% |
| Ramshot Magnum | <<locked>> | 80% | 44,237 psi | 66% | 2989 fps | 99.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,327 psi | 44% | 1962 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 41,959 psi | 63% | 3038 fps | 99.9% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 38,580 psi | 58% | 2913 fps | 95.8% |
| Rottweil R 904 | <<locked>> | 80% | 54,172 psi | 81% | 3153 fps | 99.8% |
| Rottweil R 905 | <<locked>> | 80% | 53,403 psi | 80% | 3166 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 96% | 48,066 psi | 72% | 3061 fps | 95.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 53,055 psi | 80% | 3159 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 55,376 psi | 83% | 3136 fps | 99.7% |
| Somchem S385 | <<locked>> | 80% | 53,751 psi | 81% | 3133 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 47,282 psi | 71% | 3002 fps | 99.8% |
| Vihtavuori N170 | <<locked>> | 86% | 50,082 psi | 75% | 3077 fps | 95.9% |
| Vihtavuori N555 | <<locked>> | 80% | 53,577 psi | 80% | 3133 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 52,953 psi | 79% | 3212 fps | 99.5% |
| Vihtavuori N565 | <<locked>> | 80% | 44,440 psi | 67% | 3012 fps | 98.3% |
| Vihtavuori N568 | <<locked>> | 80% | 39,566 psi | 59% | 2933 fps | 95.5% |
| Vihtavuori N570 | 96.1 gr | 86% | 47,036 psi | 71% | 3140 fps | 96% |
| Winchester StaBALL HD | <<locked>> | 80% | 49,066 psi | 74% | 3130 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 49,864 psi | 75% | 3064 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 57 powders for 7.21 Firebird loaded with the .284 | 140gr | Remington PSP. ADI AR 2218 delivers the highest muzzle velocity at 3,386 fps; across all powders the maximum-charge window runs from 2,136 fps to 3,386 fps. Accurate 8700 gives the best case fill at 100 %, and 57 of the 57 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 1:15.0 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, Hodgdon Retumbo, Vihtavuori N570 rank at the top here: for 7.21 Firebird with the .284 | 140gr | Remington PSP they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon 50BMG, Hodgdon US 869, Ramshot LRT 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.