Load Specifications
Load data in caliber 7.21 Firebird with .284 | 140gr | Nosler Expansion 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 Vihtavuori N570, Hodgdon Retumbo and ADI AR 2218.
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% | 60,205 psi | 90% | 3209 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 48,269 psi | 72% | 3097 fps | 96.2% |
| Accurate MAGPRO | <<locked>> | 86% | 59,799 psi | 90% | 3337 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 84% | 57,580 psi | 86% | 3255 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 56,492 psi | 85% | 3271 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 96% | 59,843 psi | 90% | 3310 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 56,681 psi | 85% | 3373 fps | 98.8% |
| ADI AR 2225 | <<locked>> | 98% | 59,379 psi | 89% | 3330 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 57,203 psi | 86% | 3241 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 56,898 psi | 85% | 3261 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 58,740 psi | 88% | 3215 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 59,712 psi | 90% | 3297 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 60,060 psi | 90% | 3314 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 58,624 psi | 88% | 3346 fps | 98.8% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 58,537 psi | 88% | 3333 fps | 98.4% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 56,869 psi | 85% | 3222 fps | 98.6% |
| Bofors RP15 | <<locked>> | 90% | 60,133 psi | 90% | 3314 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 59,582 psi | 89% | 3320 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 56,898 psi | 85% | 3261 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 57,145 psi | 86% | 3264 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 59,001 psi | 88% | 3258 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 86% | 58,044 psi | 87% | 3241 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 57,624 psi | 86% | 3146 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 59,350 psi | 89% | 3399 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,797 psi | 57% | 2116 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 59,466 psi | 89% | 3222 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 59,001 psi | 88% | 3232 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 88% | 58,842 psi | 88% | 3317 fps | 100% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 57,957 psi | 87% | 3307 fps | 100% |
| Lovex S071 | <<locked>> | 92% | 58,189 psi | 87% | 3179 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 59,364 psi | 89% | 3327 fps | 100% |
| Norma MRP | <<locked>> | 84% | 57,029 psi | 85% | 3278 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 56,376 psi | 85% | 3274 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 59,176 psi | 89% | 3258 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,682 psi | 58% | 2162 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 56,318 psi | 84% | 3317 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 59,872 psi | 90% | 3350 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 84% | 57,943 psi | 87% | 3219 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 84% | 56,898 psi | 85% | 3232 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 50,212 psi | 75% | 3114 fps | 96.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 56,521 psi | 85% | 3225 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 59,408 psi | 89% | 3205 fps | 99.8% |
| Somchem S365 | <<locked>> | 82% | 60,147 psi | 90% | 3209 fps | 100% |
| Somchem S385 | <<locked>> | 84% | 57,130 psi | 86% | 3192 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 57,290 psi | 86% | 3179 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 56,826 psi | 85% | 3205 fps | 97.2% |
| Vihtavuori N555 | <<locked>> | 86% | 60,365 psi | 90% | 3245 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 56,391 psi | 85% | 3281 fps | 99.7% |
| Vihtavuori N565 | <<locked>> | 90% | 57,638 psi | 86% | 3271 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 94% | 59,886 psi | 90% | 3350 fps | 99.7% |
| Vihtavuori N570 | <<locked>> | 94% | 57,246 psi | 86% | 3353 fps | 98.3% |
| Winchester StaBALL HD | <<locked>> | 88% | 60,118 psi | 90% | 3314 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 57,174 psi | 86% | 3192 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% | 45,730 psi | 69% | 2972 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 44,744 psi | 67% | 3025 fps | 95% |
| Accurate MAGPRO | <<locked>> | 80% | 48,051 psi | 72% | 3123 fps | 98.2% |
| ADI AR 2209 | <<locked>> | 80% | 50,125 psi | 75% | 3123 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 80% | 45,498 psi | 68% | 3064 fps | 98.6% |
| ADI AR 2217 | <<locked>> | 80% | 33,605 psi | 50% | 2769 fps | 95.1% |
| ADI AR 2218 | 99.9 gr | 92% | 44,860 psi | 67% | 3127 fps | 95.7% |
| ADI AR 2225 | <<locked>> | 80% | 30,850 psi | 46% | 2726 fps | 97.1% |
| Alliant Reloder-19 | <<locked>> | 80% | 50,024 psi | 75% | 3114 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 46,151 psi | 69% | 3064 fps | 99.4% |
| Alliant Reloder-23 | <<locked>> | 80% | 44,759 psi | 67% | 2989 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 38,928 psi | 58% | 2927 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 51,503 psi | 77% | 3179 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 46,499 psi | 70% | 3117 fps | 96.1% |
| Alliant Reloder-50 | <<locked>> | 94% | 46,354 psi | 69% | 3097 fps | 95.5% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 43,468 psi | 65% | 2963 fps | 95.5% |
| Bofors RP15 | <<locked>> | 80% | 42,815 psi | 64% | 2992 fps | 98.8% |
| Bofors RP30 | <<locked>> | 80% | 36,260 psi | 54% | 2848 fps | 96.3% |
| Bofors RP5 | <<locked>> | 80% | 46,151 psi | 69% | 3064 fps | 99.4% |
| Hodgdon H1000 | <<locked>> | 80% | 36,709 psi | 55% | 2854 fps | 97.1% |
| Hodgdon H4831 | <<locked>> | 80% | 47,892 psi | 72% | 3061 fps | 98.5% |
| Hodgdon H4831 SC | <<locked>> | 80% | 47,079 psi | 71% | 3045 fps | 98.4% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 53,882 psi | 81% | 3091 fps | 100% |
| Hodgdon Retumbo | 82 gr | 80% | 38,014 psi | 57% | 2976 fps | 98.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,311 psi | 42% | 1900 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 55,637 psi | 83% | 3159 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 48,501 psi | 73% | 3048 fps | 98.8% |
| IMR 7828 SSC | <<locked>> | 80% | 44,121 psi | 66% | 3041 fps | 98.3% |
| IMR 8133 Enduron | <<locked>> | 86% | 35,273 psi | 53% | 2835 fps | 95.7% |
| Lovex S071 | <<locked>> | 80% | 39,102 psi | 59% | 2831 fps | 99.6% |
| Norma 217 | <<locked>> | 82% | 30,734 psi | 46% | 2723 fps | 96% |
| Norma MRP | <<locked>> | 80% | 49,240 psi | 74% | 3143 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 44,628 psi | 67% | 3054 fps | 98.7% |
| Ramshot Magnum | <<locked>> | 80% | 40,147 psi | 60% | 2917 fps | 99% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,008 psi | 43% | 1942 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 37,623 psi | 56% | 2949 fps | 99.3% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 37,304 psi | 56% | 2894 fps | 95% |
| Rottweil R 904 | <<locked>> | 80% | 50,618 psi | 76% | 3094 fps | 99.4% |
| Rottweil R 905 | <<locked>> | 80% | 49,690 psi | 74% | 3104 fps | 99.8% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 46,731 psi | 70% | 3041 fps | 95.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 49,342 psi | 74% | 3100 fps | 99.7% |
| Somchem S361 | <<locked>> | 80% | 51,866 psi | 78% | 3081 fps | 99.2% |
| Somchem S365 | <<locked>> | 80% | 56,043 psi | 84% | 3153 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 49,966 psi | 75% | 3074 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 43,729 psi | 66% | 2940 fps | 99.4% |
| Vihtavuori N170 | <<locked>> | 88% | 49,356 psi | 74% | 3068 fps | 95.3% |
| Vihtavuori N555 | <<locked>> | 80% | 49,400 psi | 74% | 3074 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 48,791 psi | 73% | 3140 fps | 98.8% |
| Vihtavuori N565 | <<locked>> | 80% | 40,451 psi | 61% | 2933 fps | 97% |
| Vihtavuori N568 | <<locked>> | 84% | 41,495 psi | 62% | 2992 fps | 96% |
| Vihtavuori N570 | 93.6 gr | 88% | 45,730 psi | 69% | 3123 fps | 95.4% |
| Winchester StaBALL HD | <<locked>> | 80% | 43,976 psi | 66% | 3054 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 46,137 psi | 69% | 2999 fps | 99.4% |
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 60 powders for 7.21 Firebird loaded with the .284 | 140gr | Nosler Expansion Tip. Hodgdon Retumbo delivers the highest muzzle velocity at 3,399 fps; across all powders the maximum-charge window runs from 2,116 fps to 3,399 fps. Accurate 8700 gives the best case fill at 100 %, and 60 of the 60 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 1:10.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, 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. Vihtavuori N570, Hodgdon Retumbo, ADI AR 2218 rank at the top here: for 7.21 Firebird with the .284 | 140gr | Nosler Expansion Tip they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon US 869, Ramshot LRT, Vihtavuori 20N29 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.