Load Specifications
Load data in caliber 7.21 Firebird with .284 | 130gr | Fox Classic Hunter bullet and 59 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, Vihtavuori N570 and Alliant Reloder-33.
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>> | 88% | 58,247 psi | 87% | 3271 fps | 100% |
| Accurate MAGPRO | <<locked>> | 86% | 57,812 psi | 87% | 3392 fps | 99.3% |
| ADI AR 2209 | <<locked>> | 86% | 59,756 psi | 90% | 3383 fps | 100% |
| ADI AR 2213 | <<locked>> | 88% | 58,450 psi | 88% | 3392 fps | 99.8% |
| ADI AR 2217 | <<locked>> | 96% | 57,580 psi | 86% | 3363 fps | 99.9% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 58,798 psi | 88% | 3497 fps | 98.7% |
| ADI AR 2225 | <<locked>> | 98% | 56,811 psi | 85% | 3383 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 59,654 psi | 89% | 3363 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 59,074 psi | 89% | 3363 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 88% | 58,769 psi | 88% | 3386 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 56,637 psi | 85% | 3281 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 57,435 psi | 86% | 3360 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 57,696 psi | 86% | 3373 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 56,173 psi | 84% | 3389 fps | 97.9% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 56,028 psi | 84% | 3369 fps | 97.4% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 59,088 psi | 89% | 3346 fps | 98.5% |
| Bofors RP15 | <<locked>> | 90% | 58,088 psi | 87% | 3373 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 57,217 psi | 86% | 3373 fps | 99.9% |
| Bofors RP5 | <<locked>> | 88% | 58,769 psi | 88% | 3386 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 59,306 psi | 89% | 3389 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 57,203 psi | 86% | 3320 fps | 99.4% |
| Hodgdon H4831 SC | <<locked>> | 88% | 60,104 psi | 90% | 3366 fps | 99.7% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 59,538 psi | 89% | 3271 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 56,898 psi | 85% | 3455 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,623 psi | 56% | 2188 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 57,667 psi | 86% | 3287 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 58,407 psi | 88% | 3287 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 57,435 psi | 86% | 3297 fps | 99.5% |
| IMR 7828 SSC | <<locked>> | 88% | 56,753 psi | 85% | 3373 fps | 99.7% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 55,608 psi | 83% | 3356 fps | 99.8% |
| Lovex S070 | <<locked>> | 82% | 59,886 psi | 90% | 3320 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 60,017 psi | 90% | 3297 fps | 100% |
| Norma 204 | <<locked>> | 82% | 59,422 psi | 89% | 3356 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 57,014 psi | 85% | 3383 fps | 100% |
| Norma MRP | <<locked>> | 86% | 59,045 psi | 89% | 3402 fps | 100% |
| Norma URP | <<locked>> | 82% | 60,191 psi | 90% | 3337 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 58,363 psi | 87% | 3399 fps | 99.9% |
| Ramshot Hunter | <<locked>> | 82% | 59,437 psi | 89% | 3346 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 56,956 psi | 85% | 3314 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,595 psi | 58% | 2241 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 58,247 psi | 87% | 3438 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 57,435 psi | 86% | 3396 fps | 99.4% |
| Rottweil R 904 | <<locked>> | 86% | 59,973 psi | 90% | 3343 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 86% | 58,987 psi | 88% | 3356 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 59,886 psi | 90% | 3320 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 60,350 psi | 90% | 3268 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 58,595 psi | 88% | 3353 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 57,696 psi | 86% | 3264 fps | 99.5% |
| Somchem S365 | <<locked>> | 82% | 57,957 psi | 87% | 3278 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 59,132 psi | 89% | 3317 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 59,437 psi | 89% | 3304 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 59,016 psi | 88% | 3323 fps | 97% |
| Vihtavuori N555 | <<locked>> | 86% | 58,276 psi | 87% | 3314 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 58,349 psi | 87% | 3406 fps | 99.6% |
| Vihtavuori N565 | <<locked>> | 92% | 59,451 psi | 89% | 3389 fps | 99.8% |
| Vihtavuori N568 | <<locked>> | 94% | 57,696 psi | 86% | 3402 fps | 99.1% |
| Vihtavuori N570 | <<locked>> | 96% | 59,161 psi | 89% | 3474 fps | 98.1% |
| Winchester StaBALL HD | <<locked>> | 88% | 57,493 psi | 86% | 3373 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 59,422 psi | 89% | 3317 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% | 44,005 psi | 66% | 3022 fps | 99.9% |
| Accurate MAGPRO | <<locked>> | 80% | 46,369 psi | 70% | 3169 fps | 97.2% |
| ADI AR 2209 | <<locked>> | 80% | 48,559 psi | 73% | 3182 fps | 99.3% |
| ADI AR 2213 | <<locked>> | 80% | 43,700 psi | 66% | 3107 fps | 97.5% |
| ADI AR 2217 | <<locked>> | 84% | 37,275 psi | 56% | 2943 fps | 95.9% |
| ADI AR 2218 | <<locked>> | 94% | 46,601 psi | 70% | 3238 fps | 95.4% |
| ADI AR 2225 | <<locked>> | 80% | 29,631 psi | 44% | 2756 fps | 95.4% |
| Alliant Reloder-16 | <<locked>> | 80% | 55,796 psi | 84% | 3304 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 48,298 psi | 72% | 3169 fps | 99.3% |
| Alliant Reloder-22 | <<locked>> | 80% | 44,367 psi | 67% | 3110 fps | 98.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 43,033 psi | 65% | 3045 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 37,333 psi | 56% | 2972 fps | 99.5% |
| Alliant Reloder-26 | <<locked>> | 80% | 49,342 psi | 74% | 3232 fps | 100% |
| Alliant Reloder-33 | 103.3 gr | 92% | 47,993 psi | 72% | 3228 fps | 95.9% |
| Alliant Reloder-50 | <<locked>> | 96% | 47,819 psi | 72% | 3205 fps | 95.2% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 45,063 psi | 68% | 3074 fps | 95.2% |
| Bofors RP15 | <<locked>> | 80% | 41,176 psi | 62% | 3038 fps | 97.9% |
| Bofors RP30 | <<locked>> | 82% | 37,333 psi | 56% | 2956 fps | 96% |
| Bofors RP5 | <<locked>> | 80% | 44,367 psi | 67% | 3110 fps | 98.7% |
| Hodgdon H1000 | <<locked>> | 80% | 35,201 psi | 53% | 2890 fps | 95.7% |
| Hodgdon H4831 | <<locked>> | 80% | 46,340 psi | 69% | 3110 fps | 97.6% |
| Hodgdon H4831 SC | <<locked>> | 80% | 45,411 psi | 68% | 3094 fps | 97.4% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 52,112 psi | 78% | 3159 fps | 100% |
| Hodgdon Retumbo | 83.3 gr | 80% | 36,434 psi | 55% | 3012 fps | 97.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,166 psi | 42% | 1965 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 54,114 psi | 81% | 3228 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 54,708 psi | 82% | 3228 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 47,166 psi | 71% | 3104 fps | 98% |
| IMR 7828 SSC | <<locked>> | 80% | 42,453 psi | 64% | 3087 fps | 97.2% |
| IMR 8133 Enduron | <<locked>> | 88% | 36,158 psi | 54% | 2936 fps | 95.3% |
| Lovex S070 | <<locked>> | 80% | 56,057 psi | 84% | 3258 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 37,666 psi | 56% | 2881 fps | 99% |
| Norma 204 | <<locked>> | 80% | 55,317 psi | 83% | 3284 fps | 99.9% |
| Norma 217 | <<locked>> | 84% | 31,488 psi | 47% | 2818 fps | 95.5% |
| Norma MRP | <<locked>> | 80% | 47,369 psi | 71% | 3192 fps | 99.8% |
| Norma URP | <<locked>> | 80% | 56,202 psi | 84% | 3278 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 42,699 psi | 64% | 3097 fps | 97.7% |
| Ramshot Hunter | <<locked>> | 80% | 55,405 psi | 83% | 3284 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 38,392 psi | 58% | 2953 fps | 98.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,950 psi | 43% | 2014 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 35,868 psi | 54% | 2976 fps | 98.3% |
| ReloadSwiss RS 80 | <<locked>> | 86% | 41,814 psi | 63% | 3084 fps | 96% |
| Rottweil R 904 | <<locked>> | 80% | 49,197 psi | 74% | 3153 fps | 98.8% |
| Rottweil R 905 | <<locked>> | 80% | 47,935 psi | 72% | 3159 fps | 99.3% |
| Shooters World SW4350 | <<locked>> | 80% | 56,057 psi | 84% | 3258 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 56,405 psi | 85% | 3205 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 47,587 psi | 71% | 3153 fps | 99.3% |
| Somchem S361 | <<locked>> | 80% | 50,270 psi | 75% | 3133 fps | 98.5% |
| Somchem S365 | <<locked>> | 80% | 54,215 psi | 81% | 3222 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 48,225 psi | 72% | 3127 fps | 99.7% |
| Vihtavuori N165 | <<locked>> | 80% | 42,134 psi | 63% | 2986 fps | 98.7% |
| Vihtavuori N170 | <<locked>> | 90% | 51,126 psi | 77% | 3179 fps | 95.1% |
| Vihtavuori N555 | <<locked>> | 80% | 47,587 psi | 71% | 3133 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 46,992 psi | 70% | 3189 fps | 97.9% |
| Vihtavuori N565 | <<locked>> | 80% | 38,870 psi | 58% | 2972 fps | 95.7% |
| Vihtavuori N568 | <<locked>> | 86% | 42,786 psi | 64% | 3100 fps | 95.7% |
| Vihtavuori N570 | 97.2 gr | 90% | 47,210 psi | 71% | 3235 fps | 95% |
| Winchester StaBALL HD | <<locked>> | 80% | 41,771 psi | 63% | 3100 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 44,599 psi | 67% | 3051 fps | 98.8% |
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 59 powders for 7.21 Firebird loaded with the .284 | 130gr | Fox Classic Hunter. ADI AR 2218 delivers the highest muzzle velocity at 3,497 fps; across all powders the maximum-charge window runs from 2,188 fps to 3,497 fps. ADI AR 2218 gives the best case fill at 100 %, and 59 of the 59 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (460 MPa), the top charges use 56–90 %, leaving at least 10 % headroom. The 130.0 gr projectile in 0.284" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. ADI AR 2218, Alliant Reloder-50, Hodgdon TrailBoss 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, Vihtavuori N570, Alliant Reloder-33 rank at the top here: for 7.21 Firebird with the .284 | 130gr | Fox Classic Hunter 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.