Load Specifications
Load data in caliber 7.21 Firebird with .284 | 140gr | Nosler Ballistic Tip Hunting bullet and 52 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.
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Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 86% | 58,755 psi | 88% | 3182 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 50,879 psi | 76% | 3143 fps | 97% |
| Accurate MAGPRO | <<locked>> | 84% | 57,972 psi | 87% | 3301 fps | 99.6% |
| ADI AR 2209 | <<locked>> | 84% | 59,596 psi | 89% | 3281 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 58,566 psi | 88% | 3301 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 58,001 psi | 87% | 3278 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 59,335 psi | 89% | 3419 fps | 99.3% |
| ADI AR 2225 | <<locked>> | 96% | 57,798 psi | 87% | 3297 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 58,987 psi | 88% | 3268 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 59,045 psi | 89% | 3291 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 57,217 psi | 86% | 3189 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 58,044 psi | 87% | 3268 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 58,160 psi | 87% | 3281 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 56,942 psi | 85% | 3314 fps | 98.6% |
| Alliant Reloder-50 | <<locked>> | 98% | 57,290 psi | 86% | 3307 fps | 98.3% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 58,639 psi | 88% | 3251 fps | 98.9% |
| Bofors RP15 | <<locked>> | 88% | 58,407 psi | 88% | 3281 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 57,972 psi | 87% | 3291 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 59,045 psi | 89% | 3291 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 59,698 psi | 89% | 3301 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 57,130 psi | 86% | 3225 fps | 99.7% |
| Hodgdon H4831 SC | <<locked>> | 86% | 60,017 psi | 90% | 3271 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 59,611 psi | 89% | 3173 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 57,885 psi | 87% | 3369 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,942 psi | 57% | 2123 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 57,116 psi | 86% | 3199 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 86% | 57,058 psi | 86% | 3281 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 92% | 59,640 psi | 89% | 3205 fps | 96.3% |
| IMR 8133 Enduron | <<locked>> | 98% | 56,623 psi | 85% | 3281 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 57,014 psi | 85% | 3159 fps | 100% |
| Norma 217 | <<locked>> | 98% | 58,247 psi | 87% | 3304 fps | 100% |
| Norma MRP | <<locked>> | 84% | 59,321 psi | 89% | 3307 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 58,682 psi | 88% | 3307 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 57,203 psi | 86% | 3222 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,001 psi | 58% | 2172 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 58,987 psi | 88% | 3350 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 58,204 psi | 87% | 3320 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 84% | 59,683 psi | 89% | 3245 fps | 100% |
| Rottweil R 905 | <<locked>> | 84% | 59,030 psi | 88% | 3261 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 52,823 psi | 79% | 3156 fps | 97% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 58,653 psi | 88% | 3255 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 57,435 psi | 86% | 3173 fps | 99.7% |
| Somchem S385 | <<locked>> | 84% | 59,292 psi | 89% | 3222 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 59,495 psi | 89% | 3209 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 59,205 psi | 89% | 3245 fps | 97.7% |
| Vihtavuori N555 | <<locked>> | 84% | 58,755 psi | 88% | 3219 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 58,537 psi | 88% | 3310 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 90% | 60,176 psi | 90% | 3310 fps | 100% |
| Vihtavuori N568 | <<locked>> | 92% | 58,392 psi | 88% | 3323 fps | 99.6% |
| Vihtavuori N570 | <<locked>> | 94% | 59,959 psi | 90% | 3396 fps | 98.8% |
| Winchester StaBALL HD | <<locked>> | 86% | 58,494 psi | 88% | 3284 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 59,205 psi | 89% | 3219 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% | 47,964 psi | 72% | 3009 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 47,094 psi | 71% | 3068 fps | 95.9% |
| Accurate MAGPRO | <<locked>> | 80% | 50,256 psi | 75% | 3163 fps | 98.7% |
| ADI AR 2209 | <<locked>> | 80% | 52,112 psi | 78% | 3156 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 47,355 psi | 71% | 3097 fps | 98.9% |
| ADI AR 2217 | <<locked>> | 80% | 35,331 psi | 53% | 2812 fps | 96.1% |
| ADI AR 2218 | 99.2 gr | 90% | 43,729 psi | 66% | 3094 fps | 95.3% |
| ADI AR 2225 | <<locked>> | 80% | 32,764 psi | 49% | 2782 fps | 98.1% |
| Alliant Reloder-19 | <<locked>> | 80% | 51,793 psi | 78% | 3143 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 48,124 psi | 72% | 3100 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 46,818 psi | 70% | 3022 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 41,089 psi | 62% | 2969 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 53,998 psi | 81% | 3215 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 88% | 45,397 psi | 68% | 3087 fps | 95.9% |
| Alliant Reloder-50 | <<locked>> | 92% | 45,687 psi | 68% | 3081 fps | 95.4% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 45,063 psi | 68% | 2992 fps | 96.1% |
| Bofors RP15 | <<locked>> | 80% | 44,773 psi | 67% | 3031 fps | 99.2% |
| Bofors RP30 | <<locked>> | 80% | 38,305 psi | 57% | 2897 fps | 97.2% |
| Bofors RP5 | <<locked>> | 80% | 48,124 psi | 72% | 3100 fps | 99.7% |
| Hodgdon H1000 | <<locked>> | 80% | 38,508 psi | 58% | 2897 fps | 97.8% |
| Hodgdon H4831 | <<locked>> | 80% | 49,661 psi | 74% | 3091 fps | 98.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 48,849 psi | 73% | 3074 fps | 98.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 55,883 psi | 84% | 3117 fps | 100% |
| Hodgdon Retumbo | 83.3 gr | 80% | 40,161 psi | 60% | 3025 fps | 99.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,471 psi | 43% | 1906 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 50,270 psi | 75% | 3077 fps | 99.1% |
| IMR 7828 SSC | <<locked>> | 80% | 46,209 psi | 69% | 3081 fps | 98.8% |
| IMR 7977 Enduron | <<locked>> | 90% | 55,796 psi | 84% | 3140 fps | 95.5% |
| IMR 8133 Enduron | <<locked>> | 84% | 34,954 psi | 52% | 2822 fps | 95.7% |
| Lovex S071 | <<locked>> | 80% | 41,307 psi | 62% | 2877 fps | 99.8% |
| Norma 217 | <<locked>> | 80% | 30,560 psi | 46% | 2713 fps | 96% |
| Norma MRP | <<locked>> | 80% | 51,488 psi | 77% | 3176 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 46,862 psi | 70% | 3097 fps | 99.2% |
| Ramshot Magnum | <<locked>> | 80% | 42,337 psi | 63% | 2956 fps | 99.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,196 psi | 44% | 1949 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 39,813 psi | 60% | 2995 fps | 99.7% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 39,682 psi | 59% | 2949 fps | 96.1% |
| Rottweil R 904 | <<locked>> | 80% | 52,359 psi | 78% | 3120 fps | 99.6% |
| Rottweil R 905 | <<locked>> | 80% | 51,634 psi | 77% | 3136 fps | 99.9% |
| SNPE Vectan SP 13 | <<locked>> | 96% | 45,832 psi | 69% | 3018 fps | 95% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 51,300 psi | 77% | 3133 fps | 99.9% |
| Somchem S361 | <<locked>> | 80% | 53,679 psi | 80% | 3107 fps | 99.4% |
| Somchem S385 | <<locked>> | 80% | 51,924 psi | 78% | 3104 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 45,585 psi | 68% | 2972 fps | 99.6% |
| Vihtavuori N170 | <<locked>> | 86% | 48,211 psi | 72% | 3041 fps | 95.1% |
| Vihtavuori N555 | <<locked>> | 80% | 51,663 psi | 77% | 3107 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 50,894 psi | 76% | 3176 fps | 99.2% |
| Vihtavuori N565 | <<locked>> | 80% | 42,685 psi | 64% | 2979 fps | 97.7% |
| Vihtavuori N568 | <<locked>> | 82% | 40,553 psi | 61% | 2966 fps | 95.8% |
| Vihtavuori N570 | 92.9 gr | 86% | 44,817 psi | 67% | 3097 fps | 95.1% |
| Winchester StaBALL HD | <<locked>> | 80% | 46,572 psi | 70% | 3097 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 48,153 psi | 72% | 3031 fps | 99.7% |
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 | 140gr | Nosler Ballistic Tip Hunting. 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 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 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, Hodgdon US 869 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 Tip Hunting they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon 50BMG, Hodgdon US 869, Lovex D100 burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.