Load Specifications
Load data in caliber 7.21 Firebird with .284 | 130gr | Barnes X BT bullet and 50 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, ADI AR 2218 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% | 56,768 psi | 85% | 3235 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 52,054 psi | 78% | 3238 fps | 96.6% |
| Accurate MAGPRO | <<locked>> | 84% | 59,059 psi | 89% | 3406 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 84% | 60,075 psi | 90% | 3376 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 59,205 psi | 89% | 3399 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 94% | 58,552 psi | 88% | 3369 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 59,799 psi | 90% | 3507 fps | 98.9% |
| ADI AR 2225 | <<locked>> | 96% | 58,450 psi | 88% | 3399 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 59,799 psi | 90% | 3363 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 60,031 psi | 90% | 3396 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 58,189 psi | 87% | 3291 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 58,871 psi | 88% | 3369 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 59,422 psi | 89% | 3389 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 58,102 psi | 87% | 3415 fps | 98.3% |
| Alliant Reloder-50 | <<locked>> | 98% | 59,161 psi | 89% | 3415 fps | 98.1% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 58,972 psi | 88% | 3337 fps | 98.6% |
| Bofors RP15 | <<locked>> | 88% | 59,437 psi | 89% | 3386 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 59,161 psi | 89% | 3396 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 60,031 psi | 90% | 3396 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 60,191 psi | 90% | 3396 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 57,740 psi | 87% | 3317 fps | 99.5% |
| Hodgdon H4831 SC | <<locked>> | 84% | 56,869 psi | 85% | 3304 fps | 99.4% |
| Hodgdon Retumbo | <<locked>> | 90% | 58,465 psi | 88% | 3471 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,145 psi | 57% | 2195 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 57,667 psi | 86% | 3291 fps | 99.6% |
| IMR 7828 SSC | <<locked>> | 86% | 57,798 psi | 87% | 3379 fps | 99.8% |
| IMR 8133 Enduron | <<locked>> | 98% | 57,957 psi | 87% | 3386 fps | 99.9% |
| Lovex S071 | <<locked>> | 90% | 58,900 psi | 88% | 3268 fps | 100% |
| Norma 217 | <<locked>> | 98% | 59,451 psi | 89% | 3412 fps | 100% |
| Norma MRP | <<locked>> | 84% | 60,350 psi | 90% | 3412 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 59,466 psi | 89% | 3406 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 58,218 psi | 87% | 3323 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,102 psi | 59% | 2244 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 59,901 psi | 90% | 3458 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 59,379 psi | 89% | 3422 fps | 99.6% |
| Rottweil R 904 | <<locked>> | 82% | 56,666 psi | 85% | 3278 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 84% | 59,828 psi | 90% | 3356 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 54,128 psi | 81% | 3255 fps | 96.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 59,437 psi | 89% | 3356 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 58,334 psi | 87% | 3264 fps | 99.6% |
| Somchem S385 | <<locked>> | 82% | 56,840 psi | 85% | 3268 fps | 100% |
| Vihtavuori N165 | <<locked>> | 86% | 56,695 psi | 85% | 3248 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 60,365 psi | 90% | 3337 fps | 97.3% |
| Vihtavuori N555 | <<locked>> | 84% | 60,365 psi | 90% | 3330 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 59,422 psi | 89% | 3415 fps | 99.7% |
| Vihtavuori N565 | <<locked>> | 88% | 57,696 psi | 86% | 3353 fps | 99.7% |
| Vihtavuori N568 | <<locked>> | 92% | 59,422 psi | 89% | 3422 fps | 99.4% |
| Vihtavuori N570 | <<locked>> | 92% | 56,855 psi | 85% | 3422 fps | 97.7% |
| Winchester StaBALL HD | <<locked>> | 86% | 59,698 psi | 89% | 3399 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 60,147 psi | 90% | 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% | 49,879 psi | 75% | 3120 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 48,399 psi | 73% | 3166 fps | 95.6% |
| Accurate MAGPRO | <<locked>> | 80% | 51,576 psi | 77% | 3268 fps | 98.4% |
| ADI AR 2209 | <<locked>> | 80% | 52,823 psi | 79% | 3251 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 80% | 48,196 psi | 72% | 3192 fps | 98.6% |
| ADI AR 2217 | <<locked>> | 80% | 36,709 psi | 55% | 2917 fps | 95.8% |
| ADI AR 2218 | 102 gr | 92% | 48,298 psi | 72% | 3271 fps | 96.1% |
| ADI AR 2225 | <<locked>> | 80% | 34,374 psi | 52% | 2897 fps | 98.1% |
| Alliant Reloder-19 | <<locked>> | 80% | 52,663 psi | 79% | 3241 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 49,255 psi | 74% | 3202 fps | 99.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 48,109 psi | 72% | 3127 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 42,308 psi | 63% | 3074 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 55,419 psi | 83% | 3327 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 88% | 46,789 psi | 70% | 3196 fps | 95.6% |
| Alliant Reloder-50 | <<locked>> | 92% | 47,732 psi | 72% | 3199 fps | 95.3% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 45,832 psi | 69% | 3084 fps | 95.6% |
| Bofors RP15 | <<locked>> | 80% | 46,021 psi | 69% | 3133 fps | 99% |
| Bofors RP30 | <<locked>> | 80% | 39,987 psi | 60% | 3012 fps | 97.1% |
| Bofors RP5 | <<locked>> | 80% | 49,255 psi | 74% | 3202 fps | 99.5% |
| Hodgdon H1000 | <<locked>> | 80% | 39,856 psi | 60% | 3002 fps | 97.6% |
| Hodgdon H4831 | <<locked>> | 80% | 50,676 psi | 76% | 3189 fps | 98.6% |
| Hodgdon H4831 SC | <<locked>> | 80% | 49,777 psi | 75% | 3169 fps | 98.4% |
| Hodgdon Retumbo | 83.7 gr | 80% | 41,423 psi | 62% | 3133 fps | 99% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,631 psi | 43% | 1972 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 51,068 psi | 77% | 3169 fps | 98.8% |
| IMR 7828 SSC | <<locked>> | 80% | 47,166 psi | 71% | 3179 fps | 98.5% |
| IMR 8133 Enduron | <<locked>> | 84% | 36,709 psi | 55% | 2943 fps | 95.8% |
| Lovex S071 | <<locked>> | 80% | 43,439 psi | 65% | 2995 fps | 99.8% |
| Norma 217 | <<locked>> | 80% | 32,663 psi | 49% | 2848 fps | 96.4% |
| Norma MRP | <<locked>> | 80% | 52,779 psi | 79% | 3284 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 47,877 psi | 72% | 3199 fps | 98.9% |
| Ramshot Magnum | <<locked>> | 80% | 43,859 psi | 66% | 3068 fps | 99.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,544 psi | 44% | 2018 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 41,350 psi | 62% | 3110 fps | 99.7% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 38,566 psi | 58% | 2995 fps | 95% |
| Rottweil R 904 | <<locked>> | 80% | 53,330 psi | 80% | 3219 fps | 99.4% |
| Rottweil R 905 | <<locked>> | 80% | 52,707 psi | 79% | 3238 fps | 99.8% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 50,691 psi | 76% | 3189 fps | 95.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 52,344 psi | 78% | 3232 fps | 99.8% |
| Somchem S361 | <<locked>> | 80% | 54,723 psi | 82% | 3205 fps | 99.2% |
| Somchem S385 | <<locked>> | 80% | 53,200 psi | 80% | 3205 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 46,775 psi | 70% | 3071 fps | 99.5% |
| Vihtavuori N170 | <<locked>> | 88% | 52,939 psi | 79% | 3205 fps | 95.7% |
| Vihtavuori N555 | <<locked>> | 80% | 53,258 psi | 80% | 3219 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 52,011 psi | 78% | 3281 fps | 98.9% |
| Vihtavuori N565 | <<locked>> | 80% | 44,396 psi | 67% | 3094 fps | 97.6% |
| Vihtavuori N568 | <<locked>> | 82% | 42,163 psi | 63% | 3081 fps | 95.7% |
| Vihtavuori N570 | 95.5 gr | 88% | 49,443 psi | 74% | 3278 fps | 95.9% |
| Winchester StaBALL HD | <<locked>> | 80% | 48,109 psi | 72% | 3215 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 49,240 psi | 74% | 3133 fps | 99.5% |
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 | 130gr | Barnes X BT. ADI AR 2218 delivers the highest muzzle velocity at 3,507 fps; across all powders the maximum-charge window runs from 2,195 fps to 3,507 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 130.0 gr projectile in 0.284" calls for a 1:11.0 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. Hodgdon Retumbo, ADI AR 2218, Vihtavuori N570 rank at the top here: for 7.21 Firebird with the .284 | 130gr | Barnes X BT 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.