Load Specifications
Load data in caliber 7.21 Firebird with .284 | 154gr | Reichenberg HDB Universal bullet and 50 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% | 57,943 psi | 87% | 3051 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 54,679 psi | 82% | 3104 fps | 98.6% |
| Accurate MAGPRO | <<locked>> | 82% | 57,363 psi | 86% | 3173 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 82% | 58,610 psi | 88% | 3143 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 57,841 psi | 87% | 3169 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 57,667 psi | 86% | 3153 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 58,856 psi | 88% | 3301 fps | 99.7% |
| ADI AR 2225 | <<locked>> | 94% | 57,682 psi | 86% | 3176 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 58,262 psi | 87% | 3133 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 58,392 psi | 88% | 3163 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 56,724 psi | 85% | 3054 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 57,885 psi | 87% | 3140 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 56,797 psi | 85% | 3199 fps | 99.2% |
| Alliant Reloder-50 | <<locked>> | 96% | 57,217 psi | 86% | 3196 fps | 98.9% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 57,754 psi | 87% | 3123 fps | 99.3% |
| Bofors RP15 | <<locked>> | 86% | 57,769 psi | 87% | 3150 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 57,725 psi | 87% | 3169 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 58,392 psi | 88% | 3163 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 59,088 psi | 89% | 3173 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 60,017 psi | 90% | 3153 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 59,045 psi | 89% | 3140 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 57,682 psi | 86% | 3241 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,159 psi | 57% | 2037 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 59,843 psi | 90% | 3123 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 56,449 psi | 85% | 3150 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 58,595 psi | 88% | 3081 fps | 97% |
| IMR 8133 Enduron | <<locked>> | 96% | 56,594 psi | 85% | 3163 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 60,220 psi | 90% | 3084 fps | 100% |
| Norma 217 | <<locked>> | 96% | 58,407 psi | 88% | 3186 fps | 100% |
| Norma MRP | <<locked>> | 82% | 58,769 psi | 88% | 3173 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 58,059 psi | 87% | 3176 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 56,666 psi | 85% | 3097 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,117 psi | 59% | 2080 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 58,755 psi | 88% | 3222 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 57,754 psi | 87% | 3199 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 58,697 psi | 88% | 3110 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 58,291 psi | 87% | 3127 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 56,333 psi | 84% | 3114 fps | 98.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 57,928 psi | 87% | 3123 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 60,278 psi | 90% | 3100 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 58,407 psi | 88% | 3091 fps | 100% |
| Vihtavuori N165 | <<locked>> | 86% | 58,697 psi | 88% | 3077 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 58,320 psi | 87% | 3120 fps | 98.3% |
| Vihtavuori N555 | <<locked>> | 82% | 58,392 psi | 88% | 3087 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 57,972 psi | 87% | 3186 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 59,611 psi | 89% | 3182 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 57,972 psi | 87% | 3199 fps | 99.9% |
| Vihtavuori N570 | <<locked>> | 92% | 59,843 psi | 90% | 3274 fps | 99.3% |
| Winchester StaBALL HD | <<locked>> | 84% | 58,508 psi | 88% | 3156 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 58,305 psi | 87% | 3087 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% | 50,691 psi | 76% | 2943 fps | 100% |
| Accurate 8700 | <<locked>> | 94% | 43,729 psi | 66% | 2900 fps | 95.9% |
| Accurate MAGPRO | <<locked>> | 80% | 53,403 psi | 80% | 3107 fps | 99.6% |
| ADI AR 2209 | <<locked>> | 80% | 54,882 psi | 82% | 3084 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 50,198 psi | 75% | 3041 fps | 99.8% |
| ADI AR 2217 | <<locked>> | 80% | 37,768 psi | 57% | 2772 fps | 98% |
| ADI AR 2218 | 94 gr | 86% | 40,437 psi | 61% | 2913 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 80% | 35,085 psi | 53% | 2746 fps | 99.5% |
| Alliant Reloder-19 | <<locked>> | 80% | 54,491 psi | 82% | 3071 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 50,937 psi | 76% | 3038 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 49,748 psi | 75% | 2949 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 43,903 psi | 66% | 2910 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 84% | 42,047 psi | 63% | 2910 fps | 95.8% |
| Alliant Reloder-50 | <<locked>> | 88% | 42,409 psi | 64% | 2907 fps | 95.3% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 47,442 psi | 71% | 2936 fps | 97.7% |
| Bofors RP15 | <<locked>> | 80% | 47,543 psi | 71% | 2972 fps | 99.9% |
| Bofors RP30 | <<locked>> | 80% | 40,944 psi | 61% | 2854 fps | 98.7% |
| Bofors RP5 | <<locked>> | 80% | 50,937 psi | 76% | 3038 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 41,089 psi | 62% | 2851 fps | 99.2% |
| Hodgdon H4831 | <<locked>> | 80% | 52,518 psi | 79% | 3031 fps | 99.7% |
| Hodgdon H4831 SC | <<locked>> | 80% | 51,488 psi | 77% | 3015 fps | 99.6% |
| Hodgdon Retumbo | 82.5 gr | 80% | 43,149 psi | 65% | 2982 fps | 99.9% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,572 psi | 43% | 1821 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 52,634 psi | 79% | 3009 fps | 99.7% |
| IMR 7828 SSC | <<locked>> | 80% | 49,124 psi | 74% | 3025 fps | 99.7% |
| IMR 7977 Enduron | <<locked>> | 86% | 51,445 psi | 77% | 2959 fps | 95.4% |
| IMR 8133 Enduron | <<locked>> | 80% | 32,692 psi | 49% | 2661 fps | 95.8% |
| Lovex S071 | <<locked>> | 80% | 43,830 psi | 66% | 2818 fps | 100% |
| Norma 217 | <<locked>> | 80% | 33,243 psi | 50% | 2690 fps | 98.2% |
| Norma MRP | <<locked>> | 80% | 54,679 psi | 82% | 3110 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 50,111 psi | 75% | 3045 fps | 99.9% |
| Ramshot Magnum | <<locked>> | 80% | 45,295 psi | 68% | 2907 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,486 psi | 44% | 1867 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 43,062 psi | 65% | 2956 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 39,581 psi | 59% | 2844 fps | 97.1% |
| Rottweil R 904 | <<locked>> | 80% | 55,085 psi | 83% | 3054 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 54,447 psi | 82% | 3068 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 42,699 psi | 64% | 2854 fps | 95.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 54,099 psi | 81% | 3064 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 56,362 psi | 84% | 3041 fps | 99.9% |
| Somchem S385 | <<locked>> | 80% | 54,650 psi | 82% | 3031 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 48,080 psi | 72% | 2907 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 44,556 psi | 67% | 2864 fps | 95.1% |
| Vihtavuori N555 | <<locked>> | 80% | 54,578 psi | 82% | 3031 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 53,954 psi | 81% | 3117 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 80% | 45,440 psi | 68% | 2930 fps | 99% |
| Vihtavuori N568 | <<locked>> | 80% | 40,538 psi | 61% | 2861 fps | 96.8% |
| Vihtavuori N570 | 87.8 gr | 82% | 41,640 psi | 62% | 2920 fps | 95.1% |
| Winchester StaBALL HD | <<locked>> | 80% | 50,285 psi | 75% | 3035 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 50,792 psi | 76% | 2969 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 57 powders for 7.21 Firebird loaded with the .284 | 154gr | Reichenberg HDB Universal. ADI AR 2218 delivers the highest muzzle velocity at 3,301 fps; across all powders the maximum-charge window runs from 2,037 fps to 3,301 fps. Accurate 8700 gives the best case fill at 100 %, and 57 of the 57 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 154.0 gr projectile in 0.284" calls for a 1:10.0 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 | 154gr | Reichenberg HDB Universal they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon 50BMG 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.