Load Specifications
Load data in caliber 7.21 Firebird with .284 | 120gr | Prvi Partizan HP 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 Vihtavuori N568.
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% | 58,581 psi | 88% | 3373 fps | 100% |
| Accurate MAGPRO | <<locked>> | 86% | 57,711 psi | 87% | 3484 fps | 98.9% |
| ADI AR 2209 | <<locked>> | 86% | 59,437 psi | 89% | 3474 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 88% | 58,291 psi | 87% | 3484 fps | 99.6% |
| ADI AR 2217 | <<locked>> | 96% | 57,464 psi | 86% | 3455 fps | 99.8% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 58,726 psi | 88% | 3579 fps | 98.2% |
| ADI AR 2225 | <<locked>> | 98% | 56,753 psi | 85% | 3474 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 59,611 psi | 89% | 3468 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 59,350 psi | 89% | 3461 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 58,958 psi | 88% | 3458 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 88% | 58,740 psi | 88% | 3478 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 56,608 psi | 85% | 3379 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 57,392 psi | 86% | 3455 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 57,696 psi | 86% | 3471 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 56,188 psi | 84% | 3471 fps | 97.4% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 56,362 psi | 84% | 3455 fps | 96.9% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 58,827 psi | 88% | 3428 fps | 98% |
| Bofors RP15 | <<locked>> | 90% | 58,088 psi | 87% | 3468 fps | 99.9% |
| Bofors RP30 | <<locked>> | 94% | 57,421 psi | 86% | 3468 fps | 99.7% |
| Bofors RP5 | <<locked>> | 88% | 58,740 psi | 88% | 3478 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 58,972 psi | 88% | 3478 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 57,014 psi | 85% | 3406 fps | 99.1% |
| Hodgdon H4831 SC | <<locked>> | 88% | 60,031 psi | 90% | 3458 fps | 99.4% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 59,524 psi | 89% | 3369 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 56,666 psi | 85% | 3550 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,681 psi | 56% | 2277 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 57,609 psi | 86% | 3383 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 58,494 psi | 88% | 3386 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 57,174 psi | 86% | 3383 fps | 99.2% |
| IMR 7828 SSC | <<locked>> | 88% | 56,637 psi | 85% | 3465 fps | 99.5% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 55,593 psi | 83% | 3445 fps | 99.6% |
| Lovex S070 | <<locked>> | 82% | 59,814 psi | 90% | 3415 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 60,336 psi | 90% | 3399 fps | 100% |
| Norma 204 | <<locked>> | 82% | 59,205 psi | 89% | 3445 fps | 99.9% |
| Norma 217ᴾ | <<locked>> | 100% | 56,927 psi | 85% | 3471 fps | 100% |
| Norma MRP | <<locked>> | 86% | 58,987 psi | 88% | 3494 fps | 100% |
| Norma URP | <<locked>> | 82% | 60,017 psi | 90% | 3435 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 58,059 psi | 87% | 3488 fps | 99.7% |
| Ramshot Hunter | <<locked>> | 82% | 59,234 psi | 89% | 3442 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 56,826 psi | 85% | 3402 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,653 psi | 58% | 2329 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 58,146 psi | 87% | 3533 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 57,406 psi | 86% | 3484 fps | 99.1% |
| Rottweil R 904 | <<locked>> | 86% | 59,727 psi | 90% | 3435 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 86% | 58,740 psi | 88% | 3451 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 59,814 psi | 90% | 3415 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 58,334 psi | 87% | 3445 fps | 99.9% |
| Somchem S361 | <<locked>> | 84% | 57,667 psi | 86% | 3356 fps | 99.2% |
| Somchem S365 | <<locked>> | 82% | 58,015 psi | 87% | 3379 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 59,176 psi | 89% | 3412 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 59,350 psi | 89% | 3396 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 59,016 psi | 88% | 3409 fps | 96.4% |
| Vihtavuori N555 | <<locked>> | 86% | 58,334 psi | 87% | 3412 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 58,291 psi | 87% | 3497 fps | 99.3% |
| Vihtavuori N565 | <<locked>> | 92% | 59,669 psi | 89% | 3488 fps | 99.6% |
| Vihtavuori N568 | <<locked>> | 94% | 57,783 psi | 87% | 3491 fps | 98.8% |
| Vihtavuori N570 | <<locked>> | 96% | 59,088 psi | 89% | 3560 fps | 97.5% |
| Winchester StaBALL HD | <<locked>> | 88% | 57,348 psi | 86% | 3471 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 59,335 psi | 89% | 3409 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% | 44,512 psi | 67% | 3120 fps | 99.7% |
| Accurate MAGPRO | <<locked>> | 80% | 46,369 psi | 70% | 3255 fps | 96.5% |
| ADI AR 2209 | <<locked>> | 80% | 48,472 psi | 73% | 3271 fps | 98.9% |
| ADI AR 2213 | <<locked>> | 80% | 43,743 psi | 66% | 3196 fps | 96.9% |
| ADI AR 2217 | <<locked>> | 84% | 37,405 psi | 56% | 3022 fps | 95.2% |
| ADI AR 2218 | <<locked>> | 96% | 50,270 psi | 75% | 3402 fps | 95.9% |
| ADI AR 2225 | <<locked>> | 82% | 32,155 psi | 48% | 2910 fps | 96% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 48,863 psi | 73% | 3271 fps | 99% |
| Alliant Reloder-16 | <<locked>> | 80% | 55,463 psi | 83% | 3402 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 48,399 psi | 73% | 3261 fps | 99% |
| Alliant Reloder-22 | <<locked>> | 80% | 44,541 psi | 67% | 3202 fps | 98.3% |
| Alliant Reloder-23 | <<locked>> | 80% | 43,178 psi | 65% | 3140 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 37,478 psi | 56% | 3058 fps | 99.2% |
| Alliant Reloder-26 | <<locked>> | 80% | 49,443 psi | 74% | 3327 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 48,153 psi | 72% | 3310 fps | 95.2% |
| Alliant Reloder-50 | <<locked>> | 98% | 52,156 psi | 78% | 3376 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 48,240 psi | 72% | 3225 fps | 95.5% |
| Bofors RP15 | <<locked>> | 80% | 41,321 psi | 62% | 3123 fps | 97.3% |
| Bofors RP30 | <<locked>> | 82% | 37,623 psi | 56% | 3041 fps | 95.3% |
| Bofors RP5 | <<locked>> | 80% | 44,541 psi | 67% | 3202 fps | 98.3% |
| Hodgdon H1000 | <<locked>> | 82% | 38,029 psi | 57% | 3045 fps | 96.1% |
| Hodgdon H4831 | <<locked>> | 80% | 46,253 psi | 69% | 3196 fps | 97% |
| Hodgdon H4831 SC | <<locked>> | 80% | 45,498 psi | 68% | 3179 fps | 96.8% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 52,185 psi | 78% | 3258 fps | 100% |
| Hodgdon Retumbo | 85.6 gr | 80% | 36,550 psi | 55% | 3094 fps | 96.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,239 psi | 42% | 2047 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 54,012 psi | 81% | 3320 fps | 99.9% |
| IMR 4831 | <<locked>> | 80% | 54,752 psi | 82% | 3327 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 47,123 psi | 71% | 3192 fps | 97.5% |
| IMR 7828 SSC | <<locked>> | 80% | 42,409 psi | 64% | 3169 fps | 96.6% |
| IMR 8133 Enduron | <<locked>> | 90% | 39,146 psi | 59% | 3091 fps | 95.8% |
| Lovex S070 | <<locked>> | 80% | 56,115 psi | 84% | 3356 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 38,130 psi | 57% | 2976 fps | 98.7% |
| Norma 204 | <<locked>> | 80% | 55,201 psi | 83% | 3379 fps | 99.7% |
| Norma 217 | <<locked>> | 86% | 34,272 psi | 51% | 2979 fps | 96.1% |
| Norma MRP | <<locked>> | 80% | 47,572 psi | 71% | 3287 fps | 99.6% |
| Norma URP | <<locked>> | 80% | 56,188 psi | 84% | 3376 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 42,699 psi | 64% | 3186 fps | 97.1% |
| Ramshot Hunter | <<locked>> | 80% | 55,332 psi | 83% | 3379 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 38,653 psi | 58% | 3038 fps | 97.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,892 psi | 43% | 2093 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 36,114 psi | 54% | 3058 fps | 97.7% |
| ReloadSwiss RS 80 | <<locked>> | 86% | 42,076 psi | 63% | 3166 fps | 95.4% |
| Rottweil R 904 | <<locked>> | 80% | 49,168 psi | 74% | 3241 fps | 98.3% |
| Rottweil R 905 | <<locked>> | 80% | 47,950 psi | 72% | 3248 fps | 99% |
| Shooters World SW4350 | <<locked>> | 80% | 56,115 psi | 84% | 3356 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 47,601 psi | 71% | 3241 fps | 98.9% |
| Somchem S361 | <<locked>> | 80% | 50,357 psi | 75% | 3222 fps | 98.1% |
| Somchem S365 | <<locked>> | 80% | 54,201 psi | 81% | 3323 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 48,472 psi | 73% | 3222 fps | 99.5% |
| Vihtavuori N165 | <<locked>> | 80% | 42,395 psi | 64% | 3074 fps | 98.3% |
| Vihtavuori N170 | <<locked>> | 92% | 55,100 psi | 83% | 3340 fps | 95.5% |
| Vihtavuori N555 | <<locked>> | 80% | 47,834 psi | 72% | 3232 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 47,137 psi | 71% | 3278 fps | 97.3% |
| Vihtavuori N565 | <<locked>> | 80% | 39,189 psi | 59% | 3061 fps | 95.1% |
| Vihtavuori N568 | 96 gr | 86% | 42,917 psi | 64% | 3182 fps | 95% |
| Vihtavuori N570 | 102.2 gr | 92% | 51,010 psi | 76% | 3399 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 80% | 41,858 psi | 63% | 3196 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 44,759 psi | 67% | 3136 fps | 98.3% |
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 | 120gr | Prvi Partizan HP. ADI AR 2218 delivers the highest muzzle velocity at 3,579 fps; across all powders the maximum-charge window runs from 2,277 fps to 3,579 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 120.0 gr projectile in 0.284" calls for a 1:13.0 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, Vihtavuori N568 rank at the top here: for 7.21 Firebird with the .284 | 120gr | Prvi Partizan HP 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.