Load Specifications
Load data in caliber 7.21 Firebird with .284 | 140gr | Nosler Ballistic Silver Tip bullet and 53 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2218, Hodgdon Retumbo 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.
A valid access license is required to use the Personalized Load Calculator.
You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 86% | 58,711 psi | 88% | 3182 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 50,850 psi | 76% | 3143 fps | 97% |
| Accurate MAGPRO | <<locked>> | 86% | 59,205 psi | 89% | 3317 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 84% | 59,596 psi | 89% | 3281 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 58,523 psi | 88% | 3301 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 58,160 psi | 87% | 3281 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 59,277 psi | 89% | 3419 fps | 99.3% |
| ADI AR 2225 | <<locked>> | 96% | 57,754 psi | 87% | 3301 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 59,176 psi | 89% | 3268 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 59,001 psi | 88% | 3294 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 57,203 psi | 86% | 3186 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 58,189 psi | 87% | 3271 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 58,334 psi | 87% | 3281 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 57,087 psi | 86% | 3317 fps | 98.6% |
| Alliant Reloder-50 | <<locked>> | 98% | 57,261 psi | 86% | 3304 fps | 98.3% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 58,784 psi | 88% | 3255 fps | 99% |
| Bofors RP15 | <<locked>> | 88% | 58,421 psi | 88% | 3281 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 57,972 psi | 87% | 3291 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 59,001 psi | 88% | 3294 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 59,857 psi | 90% | 3304 fps | 100% |
| Hodgdon H4831 | <<locked>> | 88% | 57,130 psi | 86% | 3225 fps | 99.7% |
| Hodgdon H4831 SC | <<locked>> | 86% | 59,973 psi | 90% | 3271 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 59,567 psi | 89% | 3169 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 57,841 psi | 87% | 3373 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,927 psi | 57% | 2123 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 56,753 psi | 85% | 3163 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 57,116 psi | 86% | 3199 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 84% | 56,840 psi | 85% | 3278 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 92% | 59,596 psi | 89% | 3202 fps | 96.3% |
| IMR 8133 Enduron | <<locked>> | 98% | 56,768 psi | 85% | 3284 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 57,029 psi | 85% | 3159 fps | 100% |
| Norma 217 | <<locked>> | 98% | 58,218 psi | 87% | 3304 fps | 100% |
| Norma MRP | <<locked>> | 84% | 59,277 psi | 89% | 3307 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 57,261 psi | 86% | 3284 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 58,958 psi | 88% | 3248 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,986 psi | 58% | 2172 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 59,161 psi | 89% | 3353 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 58,175 psi | 87% | 3317 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 84% | 59,640 psi | 89% | 3245 fps | 100% |
| Rottweil R 905 | <<locked>> | 84% | 58,987 psi | 88% | 3258 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 52,808 psi | 79% | 3156 fps | 97% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 58,610 psi | 88% | 3258 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 57,392 psi | 86% | 3169 fps | 99.7% |
| Somchem S385 | <<locked>> | 84% | 59,248 psi | 89% | 3222 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 59,480 psi | 89% | 3209 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 59,176 psi | 89% | 3241 fps | 97.7% |
| Vihtavuori N555 | <<locked>> | 84% | 58,929 psi | 88% | 3222 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 58,523 psi | 88% | 3314 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 90% | 60,118 psi | 90% | 3307 fps | 100% |
| Vihtavuori N568 | <<locked>> | 92% | 58,363 psi | 87% | 3320 fps | 99.6% |
| Vihtavuori N570 | <<locked>> | 94% | 60,118 psi | 90% | 3396 fps | 98.8% |
| Winchester StaBALL HD | <<locked>> | 86% | 58,421 psi | 88% | 3287 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 82% | 56,347 psi | 84% | 3176 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% | 47,935 psi | 72% | 3009 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 47,239 psi | 71% | 3071 fps | 96% |
| Accurate MAGPRO | <<locked>> | 80% | 47,645 psi | 71% | 3104 fps | 97.6% |
| ADI AR 2209 | <<locked>> | 80% | 52,069 psi | 78% | 3156 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 47,326 psi | 71% | 3097 fps | 98.9% |
| ADI AR 2217 | <<locked>> | 80% | 35,317 psi | 53% | 2812 fps | 96% |
| ADI AR 2218 | 99.3 gr | 90% | 43,845 psi | 66% | 3097 fps | 95.3% |
| ADI AR 2225 | <<locked>> | 80% | 32,750 psi | 49% | 2779 fps | 98% |
| Alliant Reloder-19 | <<locked>> | 80% | 51,793 psi | 78% | 3143 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 48,109 psi | 72% | 3100 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 46,804 psi | 70% | 3022 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 41,046 psi | 62% | 2966 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 53,983 psi | 81% | 3212 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 88% | 45,353 psi | 68% | 3087 fps | 95.9% |
| Alliant Reloder-50 | <<locked>> | 92% | 45,643 psi | 68% | 3077 fps | 95.3% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 45,049 psi | 68% | 2995 fps | 96.1% |
| Bofors RP15 | <<locked>> | 80% | 44,744 psi | 67% | 3028 fps | 99.2% |
| Bofors RP30 | <<locked>> | 80% | 38,305 psi | 57% | 2897 fps | 97.1% |
| Bofors RP5 | <<locked>> | 80% | 48,109 psi | 72% | 3100 fps | 99.7% |
| Hodgdon H1000 | <<locked>> | 80% | 36,289 psi | 54% | 2841 fps | 97.1% |
| Hodgdon H4831 | <<locked>> | 80% | 43,918 psi | 66% | 2972 fps | 97.7% |
| Hodgdon H4831 SC | <<locked>> | 80% | 48,834 psi | 73% | 3077 fps | 98.8% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 55,840 psi | 84% | 3117 fps | 100% |
| Hodgdon Retumbo | 83.3 gr | 80% | 40,161 psi | 60% | 3028 fps | 99.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,456 psi | 43% | 1906 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 53,243 psi | 80% | 3107 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 50,256 psi | 75% | 3077 fps | 99.1% |
| IMR 7828 SSC | <<locked>> | 80% | 49,298 psi | 74% | 3143 fps | 99.3% |
| IMR 7977 Enduron | <<locked>> | 90% | 55,927 psi | 84% | 3140 fps | 95.5% |
| IMR 8133 Enduron | <<locked>> | 84% | 34,925 psi | 52% | 2822 fps | 95.7% |
| Lovex S071 | <<locked>> | 80% | 41,292 psi | 62% | 2877 fps | 99.8% |
| Norma 217 | <<locked>> | 80% | 30,661 psi | 46% | 2717 fps | 96% |
| Norma MRP | <<locked>> | 80% | 51,503 psi | 77% | 3179 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 52,837 psi | 79% | 3209 fps | 99.8% |
| Ramshot Magnum | <<locked>> | 80% | 46,630 psi | 70% | 3045 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,196 psi | 44% | 1949 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 39,798 psi | 60% | 2999 fps | 99.7% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 39,682 psi | 59% | 2946 fps | 96.1% |
| Rottweil R 904 | <<locked>> | 80% | 52,504 psi | 79% | 3127 fps | 99.6% |
| Rottweil R 905 | <<locked>> | 80% | 51,619 psi | 77% | 3136 fps | 99.9% |
| SNPE Vectan SP 13 | <<locked>> | 96% | 45,963 psi | 69% | 3022 fps | 95.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 51,271 psi | 77% | 3133 fps | 99.9% |
| Somchem S361 | <<locked>> | 80% | 53,693 psi | 80% | 3110 fps | 99.4% |
| Somchem S385 | <<locked>> | 80% | 51,924 psi | 78% | 3104 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 45,542 psi | 68% | 2972 fps | 99.6% |
| Vihtavuori N170 | <<locked>> | 86% | 48,167 psi | 72% | 3041 fps | 95.1% |
| Vihtavuori N555 | <<locked>> | 80% | 51,648 psi | 77% | 3107 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 50,865 psi | 76% | 3176 fps | 99.1% |
| Vihtavuori N565 | <<locked>> | 80% | 42,685 psi | 64% | 2979 fps | 97.8% |
| Vihtavuori N568 | <<locked>> | 82% | 40,553 psi | 61% | 2966 fps | 95.8% |
| Vihtavuori N570 | 92.9 gr | 86% | 44,817 psi | 67% | 3100 fps | 95.1% |
| Winchester StaBALL HD | <<locked>> | 80% | 46,543 psi | 70% | 3097 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 52,417 psi | 79% | 3110 fps | 99.9% |
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 Ballistic Silver Tip. ADI AR 2218 delivers the highest muzzle velocity at 3,419 fps; across all powders the maximum-charge window runs from 2,123 fps to 3,419 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. ADI AR 2218, Hodgdon Retumbo, Vihtavuori N570 rank at the top here: for 7.21 Firebird with the .284 | 140gr | Nosler Ballistic Silver Tip 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.