Load Specifications
Load data in caliber 7.21 Firebird with .284 | 150gr | Nosler SP SolBase bullet and 49 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>> | 84% | 58,204 psi | 87% | 3087 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 55,085 psi | 83% | 3140 fps | 98.5% |
| Accurate MAGPRO | <<locked>> | 82% | 57,537 psi | 86% | 3209 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 82% | 58,958 psi | 88% | 3182 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 58,073 psi | 87% | 3205 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 57,914 psi | 87% | 3189 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 59,161 psi | 89% | 3337 fps | 99.6% |
| ADI AR 2225 | <<locked>> | 94% | 58,044 psi | 87% | 3212 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 58,378 psi | 88% | 3166 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 58,639 psi | 88% | 3196 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 56,884 psi | 85% | 3091 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 58,030 psi | 87% | 3176 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 56,956 psi | 85% | 3232 fps | 99.1% |
| Alliant Reloder-50 | <<locked>> | 96% | 57,653 psi | 86% | 3228 fps | 98.9% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 57,972 psi | 87% | 3156 fps | 99.3% |
| Bofors RP15 | <<locked>> | 86% | 58,015 psi | 87% | 3186 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 57,986 psi | 87% | 3202 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 58,639 psi | 88% | 3196 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 59,364 psi | 89% | 3205 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 60,234 psi | 90% | 3189 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 59,277 psi | 89% | 3176 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 58,030 psi | 87% | 3278 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,145 psi | 57% | 2067 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 59,915 psi | 90% | 3159 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 56,710 psi | 85% | 3186 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 58,856 psi | 88% | 3117 fps | 97% |
| IMR 8133 Enduron | <<locked>> | 96% | 56,927 psi | 85% | 3199 fps | 100% |
| Lovex S071 | <<locked>> | 88% | 56,724 psi | 85% | 3064 fps | 100% |
| Norma 217 | <<locked>> | 96% | 58,566 psi | 88% | 3219 fps | 100% |
| Norma MRP | <<locked>> | 82% | 58,798 psi | 88% | 3205 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 58,465 psi | 88% | 3215 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 56,913 psi | 85% | 3130 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,073 psi | 59% | 2110 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 59,132 psi | 89% | 3258 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 58,189 psi | 87% | 3232 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 82% | 58,871 psi | 88% | 3146 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 58,450 psi | 88% | 3163 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 56,608 psi | 85% | 3143 fps | 98.4% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 58,088 psi | 87% | 3159 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 58,508 psi | 88% | 3123 fps | 100% |
| Vihtavuori N165 | <<locked>> | 86% | 58,871 psi | 88% | 3114 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 58,624 psi | 88% | 3156 fps | 98.2% |
| Vihtavuori N555 | <<locked>> | 82% | 58,392 psi | 88% | 3120 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 58,001 psi | 87% | 3215 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 59,872 psi | 90% | 3215 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 58,276 psi | 87% | 3235 fps | 99.8% |
| Vihtavuori N570 | <<locked>> | 92% | 60,118 psi | 90% | 3310 fps | 99.2% |
| Winchester StaBALL HD | <<locked>> | 84% | 58,697 psi | 88% | 3192 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 58,508 psi | 88% | 3123 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% | 50,865 psi | 76% | 2976 fps | 100% |
| Accurate 8700 | <<locked>> | 94% | 44,077 psi | 66% | 2930 fps | 95.8% |
| Accurate MAGPRO | <<locked>> | 80% | 53,635 psi | 80% | 3140 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 80% | 55,071 psi | 83% | 3120 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 50,372 psi | 76% | 3071 fps | 99.7% |
| ADI AR 2217 | <<locked>> | 80% | 37,826 psi | 57% | 2802 fps | 97.8% |
| ADI AR 2218 | 95.9 gr | 86% | 40,611 psi | 61% | 2943 fps | 95% |
| ADI AR 2225 | <<locked>> | 80% | 35,244 psi | 53% | 2776 fps | 99.4% |
| Alliant Reloder-19 | <<locked>> | 80% | 54,694 psi | 82% | 3107 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 51,111 psi | 77% | 3071 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 49,835 psi | 75% | 2982 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 44,092 psi | 66% | 2943 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 84% | 42,235 psi | 63% | 2936 fps | 95.6% |
| Alliant Reloder-50 | <<locked>> | 88% | 42,685 psi | 64% | 2933 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 47,630 psi | 71% | 2972 fps | 97.6% |
| Bofors RP15 | <<locked>> | 80% | 47,616 psi | 71% | 3005 fps | 99.8% |
| Bofors RP30 | <<locked>> | 80% | 41,133 psi | 62% | 2884 fps | 98.6% |
| Bofors RP5 | <<locked>> | 80% | 51,111 psi | 77% | 3071 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 41,205 psi | 62% | 2884 fps | 99.1% |
| Hodgdon H4831 | <<locked>> | 80% | 52,649 psi | 79% | 3064 fps | 99.6% |
| Hodgdon H4831 SC | <<locked>> | 80% | 51,648 psi | 77% | 3048 fps | 99.6% |
| Hodgdon Retumbo | 84.2 gr | 80% | 43,337 psi | 65% | 3012 fps | 99.9% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,616 psi | 43% | 1850 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 52,837 psi | 79% | 3045 fps | 99.7% |
| IMR 7828 SSC | <<locked>> | 80% | 49,284 psi | 74% | 3058 fps | 99.6% |
| IMR 7977 Enduron | <<locked>> | 86% | 51,590 psi | 77% | 2989 fps | 95.3% |
| IMR 8133 Enduron | <<locked>> | 80% | 32,750 psi | 49% | 2687 fps | 95.5% |
| Lovex S071 | <<locked>> | 80% | 43,947 psi | 66% | 2848 fps | 100% |
| Norma 217 | <<locked>> | 80% | 33,301 psi | 50% | 2713 fps | 97.9% |
| Norma MRP | <<locked>> | 80% | 54,969 psi | 82% | 3146 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 50,241 psi | 75% | 3077 fps | 99.8% |
| Ramshot Magnum | <<locked>> | 80% | 45,513 psi | 68% | 2940 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,501 psi | 44% | 1896 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 43,265 psi | 65% | 2989 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 39,755 psi | 60% | 2871 fps | 96.9% |
| Rottweil R 904 | <<locked>> | 80% | 55,114 psi | 83% | 3087 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 54,650 psi | 82% | 3104 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 42,946 psi | 64% | 2884 fps | 95% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 54,302 psi | 81% | 3097 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 54,824 psi | 82% | 3064 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 48,254 psi | 72% | 2940 fps | 100% |
| Vihtavuori N170 | <<locked>> | 84% | 47,761 psi | 72% | 2956 fps | 95.8% |
| Vihtavuori N555 | <<locked>> | 80% | 54,810 psi | 82% | 3068 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 54,244 psi | 81% | 3153 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 80% | 45,542 psi | 68% | 2963 fps | 98.9% |
| Vihtavuori N568 | <<locked>> | 80% | 40,611 psi | 61% | 2890 fps | 96.6% |
| Vihtavuori N570 | 91.7 gr | 84% | 44,889 psi | 67% | 3022 fps | 96% |
| Winchester StaBALL HD | <<locked>> | 80% | 50,589 psi | 76% | 3068 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 50,937 psi | 76% | 3002 fps | 100% |
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 56 powders for 7.21 Firebird loaded with the .284 | 150gr | Nosler SP SolBase. ADI AR 2218 delivers the highest muzzle velocity at 3,337 fps; across all powders the maximum-charge window runs from 2,067 fps to 3,337 fps. Accurate 8700 gives the best case fill at 100 %, and 56 of the 56 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 150.0 gr projectile in 0.284" calls for a 1:12.0 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 | 150gr | Nosler SP SolBase they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon 50BMG, Vihtavuori 24N41 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.