Load Specifications
Load data in caliber 7.21 Firebird with .284 | 140gr | Nosler AccuBond bullet and 53 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>> | 86% | 58,595 psi | 88% | 3182 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 50,734 psi | 76% | 3140 fps | 96.9% |
| Accurate MAGPRO | <<locked>> | 84% | 57,812 psi | 87% | 3301 fps | 99.6% |
| ADI AR 2209 | <<locked>> | 84% | 59,466 psi | 89% | 3278 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 58,407 psi | 88% | 3301 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 57,856 psi | 87% | 3274 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 59,001 psi | 88% | 3415 fps | 99.2% |
| ADI AR 2225 | <<locked>> | 96% | 57,653 psi | 86% | 3301 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 84% | 59,683 psi | 89% | 3274 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 59,045 psi | 89% | 3268 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 58,885 psi | 88% | 3291 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 57,043 psi | 86% | 3186 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 58,073 psi | 87% | 3268 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 57,986 psi | 87% | 3278 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 56,797 psi | 85% | 3310 fps | 98.6% |
| Alliant Reloder-50 | <<locked>> | 98% | 57,145 psi | 86% | 3304 fps | 98.3% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 58,537 psi | 88% | 3248 fps | 98.9% |
| Bofors RP15 | <<locked>> | 88% | 58,247 psi | 87% | 3281 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 57,827 psi | 87% | 3291 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 58,885 psi | 88% | 3291 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 59,553 psi | 89% | 3301 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 56,971 psi | 85% | 3222 fps | 99.7% |
| Hodgdon H4831 SC | <<locked>> | 86% | 59,857 psi | 90% | 3268 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 59,422 psi | 89% | 3169 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 57,711 psi | 87% | 3369 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,898 psi | 57% | 2123 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 57,014 psi | 85% | 3196 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 86% | 56,884 psi | 85% | 3281 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 92% | 59,509 psi | 89% | 3202 fps | 96.3% |
| IMR 8133 Enduron | <<locked>> | 98% | 56,463 psi | 85% | 3281 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 56,898 psi | 85% | 3156 fps | 100% |
| Norma 217 | <<locked>> | 98% | 58,102 psi | 87% | 3304 fps | 100% |
| Norma MRP | <<locked>> | 84% | 59,161 psi | 89% | 3304 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 58,508 psi | 88% | 3304 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 57,058 psi | 86% | 3222 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,957 psi | 58% | 2172 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 58,784 psi | 88% | 3350 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 58,088 psi | 87% | 3317 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 84% | 59,524 psi | 89% | 3245 fps | 100% |
| Rottweil R 905 | <<locked>> | 84% | 58,856 psi | 88% | 3258 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 52,547 psi | 79% | 3150 fps | 96.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 58,479 psi | 88% | 3255 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 57,305 psi | 86% | 3169 fps | 99.7% |
| Somchem S385 | <<locked>> | 84% | 59,132 psi | 89% | 3222 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 59,350 psi | 89% | 3209 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 59,088 psi | 89% | 3241 fps | 97.7% |
| Vihtavuori N555 | <<locked>> | 84% | 58,784 psi | 88% | 3219 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 58,392 psi | 88% | 3310 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 90% | 60,031 psi | 90% | 3307 fps | 100% |
| Vihtavuori N568 | <<locked>> | 92% | 58,262 psi | 87% | 3320 fps | 99.6% |
| Vihtavuori N570 | <<locked>> | 94% | 59,799 psi | 90% | 3392 fps | 98.7% |
| Winchester StaBALL HD | <<locked>> | 86% | 58,349 psi | 87% | 3284 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 59,248 psi | 89% | 3222 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% | 47,805 psi | 72% | 3005 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 46,978 psi | 70% | 3068 fps | 95.9% |
| Accurate MAGPRO | <<locked>> | 80% | 50,125 psi | 75% | 3159 fps | 98.6% |
| ADI AR 2209 | <<locked>> | 80% | 51,938 psi | 78% | 3153 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 47,195 psi | 71% | 3094 fps | 98.9% |
| ADI AR 2217 | <<locked>> | 80% | 35,215 psi | 53% | 2808 fps | 96% |
| ADI AR 2218 | 99 gr | 90% | 43,598 psi | 65% | 3091 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 80% | 32,648 psi | 49% | 2779 fps | 98% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 52,156 psi | 78% | 3150 fps | 99.9% |
| Alliant Reloder-19 | <<locked>> | 80% | 51,677 psi | 77% | 3143 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 47,979 psi | 72% | 3097 fps | 99.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 46,659 psi | 70% | 3018 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 40,915 psi | 61% | 2966 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 53,853 psi | 81% | 3215 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 88% | 45,223 psi | 68% | 3087 fps | 95.8% |
| Alliant Reloder-50 | <<locked>> | 92% | 45,556 psi | 68% | 3077 fps | 95.3% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 44,933 psi | 67% | 2992 fps | 96.1% |
| Bofors RP15 | <<locked>> | 80% | 44,614 psi | 67% | 3028 fps | 99.1% |
| Bofors RP30 | <<locked>> | 80% | 38,189 psi | 57% | 2894 fps | 97.1% |
| Bofors RP5 | <<locked>> | 80% | 47,979 psi | 72% | 3097 fps | 99.6% |
| Hodgdon H1000 | <<locked>> | 80% | 38,363 psi | 57% | 2894 fps | 97.8% |
| Hodgdon H4831 | <<locked>> | 80% | 49,690 psi | 74% | 3094 fps | 98.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 48,718 psi | 73% | 3071 fps | 98.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 55,695 psi | 83% | 3117 fps | 100% |
| Hodgdon Retumbo | 83.1 gr | 80% | 40,030 psi | 60% | 3022 fps | 99.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,413 psi | 43% | 1903 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 50,140 psi | 75% | 3074 fps | 99.1% |
| IMR 7828 SSC | <<locked>> | 80% | 46,035 psi | 69% | 3077 fps | 98.7% |
| IMR 7977 Enduron | <<locked>> | 90% | 55,666 psi | 83% | 3136 fps | 95.4% |
| IMR 8133 Enduron | <<locked>> | 84% | 34,809 psi | 52% | 2818 fps | 95.6% |
| Lovex S071 | <<locked>> | 80% | 41,147 psi | 62% | 2874 fps | 99.8% |
| Norma 217 | <<locked>> | 80% | 30,560 psi | 46% | 2713 fps | 96% |
| Norma MRP | <<locked>> | 80% | 51,329 psi | 77% | 3176 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 46,717 psi | 70% | 3097 fps | 99.1% |
| Ramshot Magnum | <<locked>> | 80% | 42,177 psi | 63% | 2953 fps | 99.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,283 psi | 44% | 1949 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 39,682 psi | 59% | 2995 fps | 99.7% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 39,581 psi | 59% | 2946 fps | 96.1% |
| Rottweil R 904 | <<locked>> | 80% | 52,373 psi | 79% | 3123 fps | 99.6% |
| Rottweil R 905 | <<locked>> | 80% | 51,474 psi | 77% | 3133 fps | 99.9% |
| SNPE Vectan SP 13 | <<locked>> | 96% | 45,687 psi | 68% | 3018 fps | 95% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 51,126 psi | 77% | 3130 fps | 99.9% |
| Somchem S361 | <<locked>> | 80% | 53,592 psi | 80% | 3107 fps | 99.4% |
| Somchem S385 | <<locked>> | 80% | 51,808 psi | 78% | 3100 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 45,426 psi | 68% | 2969 fps | 99.6% |
| Vihtavuori N170 | <<locked>> | 86% | 48,080 psi | 72% | 3038 fps | 95.1% |
| Vihtavuori N555 | <<locked>> | 80% | 51,503 psi | 77% | 3104 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 50,734 psi | 76% | 3176 fps | 99.1% |
| Vihtavuori N565 | <<locked>> | 80% | 42,569 psi | 64% | 2976 fps | 97.7% |
| Vihtavuori N568 | <<locked>> | 82% | 40,408 psi | 61% | 2963 fps | 95.7% |
| Vihtavuori N570 | 92.7 gr | 86% | 44,672 psi | 67% | 3094 fps | 95.1% |
| Winchester StaBALL HD | <<locked>> | 80% | 46,398 psi | 70% | 3094 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 48,008 psi | 72% | 3028 fps | 99.6% |
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 53 powders for 7.21 Firebird loaded with the .284 | 140gr | Nosler AccuBond. ADI AR 2218 delivers the highest muzzle velocity at 3,415 fps; across all powders the maximum-charge window runs from 2,123 fps to 3,415 fps. Accurate 8700 gives the best case fill at 100 %, and 53 of the 53 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 1:11.0 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 | 140gr | Nosler AccuBond 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.