Load Specifications
Load data in caliber 7.21 Firebird with .284 | 140gr | Nosler CT FailSafe 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% | 59,698 psi | 89% | 3196 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 52,112 psi | 78% | 3163 fps | 97.3% |
| Accurate MAGPRO | <<locked>> | 84% | 59,117 psi | 89% | 3320 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 82% | 56,652 psi | 85% | 3232 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 59,524 psi | 89% | 3314 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 59,364 psi | 89% | 3297 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 56,057 psi | 84% | 3360 fps | 98.9% |
| ADI AR 2225 | <<locked>> | 96% | 59,146 psi | 89% | 3314 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 59,944 psi | 90% | 3281 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 60,031 psi | 90% | 3304 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 58,262 psi | 87% | 3199 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 59,234 psi | 89% | 3281 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 59,451 psi | 89% | 3294 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 58,305 psi | 87% | 3333 fps | 98.9% |
| Alliant Reloder-50 | <<locked>> | 98% | 58,842 psi | 88% | 3330 fps | 98.6% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 59,683 psi | 89% | 3268 fps | 99.1% |
| Bofors RP15 | <<locked>> | 88% | 59,379 psi | 89% | 3294 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 59,132 psi | 89% | 3307 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 60,031 psi | 90% | 3304 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 56,666 psi | 85% | 3251 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 58,073 psi | 87% | 3238 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 84% | 56,971 psi | 85% | 3222 fps | 99.7% |
| Hodgdon Retumbo | <<locked>> | 90% | 59,219 psi | 89% | 3386 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,898 psi | 57% | 2126 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 57,986 psi | 87% | 3215 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 86% | 58,073 psi | 87% | 3297 fps | 100% |
| IMR 8133 Enduron | <<locked>> | 98% | 57,885 psi | 87% | 3297 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 58,030 psi | 87% | 3173 fps | 100% |
| Norma 217 | <<locked>> | 98% | 59,611 psi | 89% | 3320 fps | 100% |
| Norma MRP | <<locked>> | 82% | 56,405 psi | 85% | 3258 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 59,944 psi | 90% | 3323 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 58,494 psi | 88% | 3241 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,943 psi | 58% | 2175 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 55,985 psi | 84% | 3301 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 59,654 psi | 89% | 3340 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 82% | 56,753 psi | 85% | 3199 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 84% | 60,031 psi | 90% | 3274 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 53,882 psi | 81% | 3176 fps | 97.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 59,654 psi | 89% | 3271 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 58,407 psi | 88% | 3186 fps | 99.8% |
| Somchem S385 | <<locked>> | 84% | 60,220 psi | 90% | 3235 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 60,365 psi | 90% | 3219 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 60,307 psi | 90% | 3258 fps | 98% |
| Vihtavuori N555 | <<locked>> | 84% | 59,843 psi | 90% | 3232 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 59,683 psi | 89% | 3330 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 88% | 57,334 psi | 86% | 3261 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 92% | 59,654 psi | 89% | 3340 fps | 99.7% |
| Vihtavuori N570 | <<locked>> | 92% | 57,159 psi | 86% | 3343 fps | 98.4% |
| Winchester StaBALL HD | <<locked>> | 86% | 59,872 psi | 90% | 3301 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 60,263 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% | 48,747 psi | 73% | 3022 fps | 100% |
| Accurate 8700 | <<locked>> | 96% | 44,788 psi | 67% | 3018 fps | 95.2% |
| Accurate MAGPRO | <<locked>> | 80% | 51,198 psi | 77% | 3179 fps | 98.9% |
| ADI AR 2209 | <<locked>> | 80% | 52,924 psi | 79% | 3169 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 48,153 psi | 72% | 3114 fps | 99.1% |
| ADI AR 2217 | <<locked>> | 80% | 36,013 psi | 54% | 2828 fps | 96.4% |
| ADI AR 2218 | 100.8 gr | 90% | 44,715 psi | 67% | 3114 fps | 95.8% |
| ADI AR 2225 | <<locked>> | 80% | 33,417 psi | 50% | 2795 fps | 98.3% |
| Alliant Reloder-19 | <<locked>> | 80% | 52,605 psi | 79% | 3156 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 48,921 psi | 73% | 3114 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 47,688 psi | 71% | 3035 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 41,901 psi | 63% | 2982 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 55,071 psi | 83% | 3228 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 86% | 43,076 psi | 65% | 3031 fps | 95.1% |
| Alliant Reloder-50 | <<locked>> | 92% | 46,789 psi | 70% | 3100 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 45,788 psi | 69% | 3009 fps | 96.4% |
| Bofors RP15 | <<locked>> | 80% | 45,571 psi | 68% | 3045 fps | 99.3% |
| Bofors RP30 | <<locked>> | 80% | 39,088 psi | 59% | 2913 fps | 97.5% |
| Bofors RP5 | <<locked>> | 80% | 48,921 psi | 73% | 3114 fps | 99.8% |
| Hodgdon H1000 | <<locked>> | 80% | 39,349 psi | 59% | 2917 fps | 98.1% |
| Hodgdon H4831 | <<locked>> | 80% | 50,560 psi | 76% | 3107 fps | 99.1% |
| Hodgdon H4831 SC | <<locked>> | 80% | 49,588 psi | 74% | 3087 fps | 98.9% |
| Hodgdon Retumbo | 84.6 gr | 80% | 41,002 psi | 61% | 3041 fps | 99.4% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,442 psi | 43% | 1909 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 50,981 psi | 76% | 3091 fps | 99.2% |
| IMR 7828 SSC | <<locked>> | 80% | 47,021 psi | 70% | 3097 fps | 99% |
| IMR 8133 Enduron | <<locked>> | 84% | 35,694 psi | 54% | 2838 fps | 96.1% |
| Lovex S071 | <<locked>> | 80% | 42,105 psi | 63% | 2890 fps | 99.9% |
| Norma 217 | <<locked>> | 80% | 31,328 psi | 47% | 2730 fps | 96.4% |
| Norma MRP | <<locked>> | 80% | 52,518 psi | 79% | 3192 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 47,892 psi | 72% | 3117 fps | 99.3% |
| Ramshot Magnum | <<locked>> | 80% | 43,236 psi | 65% | 2972 fps | 99.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,298 psi | 44% | 1955 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 40,727 psi | 61% | 3015 fps | 99.8% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 37,637 psi | 56% | 2894 fps | 95.3% |
| Rottweil R 904 | <<locked>> | 80% | 53,127 psi | 80% | 3136 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 80% | 52,475 psi | 79% | 3153 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 96% | 46,818 psi | 70% | 3038 fps | 95.4% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 52,127 psi | 78% | 3146 fps | 99.9% |
| Somchem S361 | <<locked>> | 80% | 54,520 psi | 82% | 3123 fps | 99.5% |
| Somchem S385 | <<locked>> | 80% | 52,707 psi | 79% | 3117 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 46,296 psi | 69% | 2986 fps | 99.7% |
| Vihtavuori N170 | <<locked>> | 86% | 49,095 psi | 74% | 3058 fps | 95.5% |
| Vihtavuori N555 | <<locked>> | 80% | 52,562 psi | 79% | 3120 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 51,880 psi | 78% | 3196 fps | 99.3% |
| Vihtavuori N565 | <<locked>> | 80% | 43,439 psi | 65% | 2992 fps | 98% |
| Vihtavuori N568 | <<locked>> | 80% | 38,479 psi | 58% | 2910 fps | 95% |
| Vihtavuori N570 | 94.4 gr | 86% | 45,890 psi | 69% | 3117 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 80% | 47,747 psi | 72% | 3110 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 48,863 psi | 73% | 3048 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 50 powders for 7.21 Firebird loaded with the .284 | 140gr | Nosler CT FailSafe. Hodgdon Retumbo delivers the highest muzzle velocity at 3,386 fps; across all powders the maximum-charge window runs from 2,126 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 | Nosler CT FailSafe 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.