Load Specifications
Load data in caliber 7.21 Firebird with .284 | 150gr | Rhino Solid Shank 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% | 58,175 psi | 87% | 3087 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 54,882 psi | 82% | 3136 fps | 98.4% |
| Accurate MAGPRO | <<locked>> | 82% | 57,508 psi | 86% | 3209 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 82% | 58,711 psi | 88% | 3179 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 57,841 psi | 87% | 3199 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 57,870 psi | 87% | 3186 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 59,161 psi | 89% | 3333 fps | 99.6% |
| ADI AR 2225 | <<locked>> | 94% | 58,030 psi | 87% | 3209 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 58,363 psi | 87% | 3166 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 58,392 psi | 88% | 3192 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 56,840 psi | 85% | 3091 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 58,030 psi | 87% | 3173 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 56,942 psi | 85% | 3228 fps | 99.1% |
| Alliant Reloder-50 | <<locked>> | 96% | 57,450 psi | 86% | 3225 fps | 98.8% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 57,972 psi | 87% | 3159 fps | 99.3% |
| Bofors RP15 | <<locked>> | 86% | 57,972 psi | 87% | 3186 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 57,798 psi | 87% | 3199 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 58,392 psi | 88% | 3192 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 59,350 psi | 89% | 3205 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 60,205 psi | 90% | 3186 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 59,059 psi | 89% | 3169 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 58,015 psi | 87% | 3278 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,058 psi | 57% | 2064 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 59,886 psi | 90% | 3156 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 56,695 psi | 85% | 3189 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 58,682 psi | 88% | 3114 fps | 96.9% |
| IMR 8133 Enduron | <<locked>> | 96% | 56,739 psi | 85% | 3196 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 60,263 psi | 90% | 3117 fps | 100% |
| Norma 217 | <<locked>> | 96% | 58,552 psi | 88% | 3219 fps | 100% |
| Norma MRP | <<locked>> | 82% | 58,784 psi | 88% | 3205 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 58,233 psi | 87% | 3209 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 56,695 psi | 85% | 3130 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,160 psi | 59% | 2113 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 59,117 psi | 89% | 3258 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 57,986 psi | 87% | 3228 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 82% | 58,856 psi | 88% | 3146 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 58,233 psi | 87% | 3159 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 56,608 psi | 85% | 3143 fps | 98.4% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 57,870 psi | 87% | 3153 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 58,479 psi | 88% | 3123 fps | 100% |
| Vihtavuori N165 | <<locked>> | 86% | 58,827 psi | 88% | 3114 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 58,421 psi | 88% | 3150 fps | 98.2% |
| Vihtavuori N555 | <<locked>> | 82% | 58,334 psi | 87% | 3120 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 57,957 psi | 87% | 3215 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 59,828 psi | 90% | 3215 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 58,059 psi | 87% | 3228 fps | 99.8% |
| Vihtavuori N570 | <<locked>> | 92% | 59,915 psi | 90% | 3307 fps | 99.2% |
| Winchester StaBALL HD | <<locked>> | 84% | 58,494 psi | 88% | 3186 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 58,479 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% | 50,836 psi | 76% | 2972 fps | 100% |
| Accurate 8700 | <<locked>> | 94% | 43,888 psi | 66% | 2927 fps | 95.7% |
| Accurate MAGPRO | <<locked>> | 80% | 53,592 psi | 80% | 3140 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 80% | 54,868 psi | 82% | 3117 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 50,343 psi | 75% | 3071 fps | 99.7% |
| ADI AR 2217 | <<locked>> | 80% | 37,782 psi | 57% | 2802 fps | 97.8% |
| ADI AR 2218 | 98 gr | 88% | 43,671 psi | 65% | 3018 fps | 96.3% |
| ADI AR 2225 | <<locked>> | 80% | 35,201 psi | 53% | 2776 fps | 99.4% |
| Alliant Reloder-19 | <<locked>> | 80% | 54,636 psi | 82% | 3107 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 51,082 psi | 77% | 3071 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 49,806 psi | 75% | 2982 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 43,888 psi | 66% | 2940 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 84% | 42,076 psi | 63% | 2936 fps | 95.5% |
| Alliant Reloder-50 | <<locked>> | 88% | 42,656 psi | 64% | 2933 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 47,456 psi | 71% | 2966 fps | 97.5% |
| Bofors RP15 | <<locked>> | 80% | 47,558 psi | 71% | 3002 fps | 99.8% |
| Bofors RP30 | <<locked>> | 80% | 41,075 psi | 62% | 2884 fps | 98.6% |
| Bofors RP5 | <<locked>> | 80% | 51,082 psi | 77% | 3071 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 41,191 psi | 62% | 2881 fps | 99.1% |
| Hodgdon H4831 | <<locked>> | 80% | 52,620 psi | 79% | 3064 fps | 99.6% |
| Hodgdon H4831 SC | <<locked>> | 80% | 51,634 psi | 77% | 3045 fps | 99.5% |
| Hodgdon Retumbo | 84.1 gr | 80% | 43,279 psi | 65% | 3012 fps | 99.9% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,660 psi | 43% | 1854 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 52,649 psi | 79% | 3038 fps | 99.7% |
| IMR 7828 SSC | <<locked>> | 80% | 49,255 psi | 74% | 3058 fps | 99.6% |
| IMR 7977 Enduron | <<locked>> | 86% | 51,576 psi | 77% | 2989 fps | 95.3% |
| IMR 8133 Enduron | <<locked>> | 80% | 32,735 psi | 49% | 2684 fps | 95.5% |
| Lovex S071 | <<locked>> | 80% | 43,918 psi | 66% | 2848 fps | 100% |
| Norma 217 | <<locked>> | 80% | 33,272 psi | 50% | 2713 fps | 97.9% |
| Norma MRP | <<locked>> | 80% | 54,766 psi | 82% | 3143 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 50,227 psi | 75% | 3077 fps | 99.8% |
| Ramshot Magnum | <<locked>> | 80% | 45,324 psi | 68% | 2936 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,428 psi | 44% | 1893 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 43,207 psi | 65% | 2986 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 39,682 psi | 59% | 2867 fps | 96.9% |
| Rottweil R 904 | <<locked>> | 80% | 55,100 psi | 83% | 3084 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 54,607 psi | 82% | 3104 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 94% | 45,963 psi | 69% | 2946 fps | 95.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 54,259 psi | 81% | 3097 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 54,766 psi | 82% | 3064 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 48,240 psi | 72% | 2940 fps | 100% |
| Vihtavuori N170 | <<locked>> | 84% | 47,747 psi | 72% | 2959 fps | 95.8% |
| Vihtavuori N555 | <<locked>> | 80% | 54,781 psi | 82% | 3064 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 54,041 psi | 81% | 3146 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 80% | 45,498 psi | 68% | 2959 fps | 98.9% |
| Vihtavuori N568 | <<locked>> | 80% | 40,567 psi | 61% | 2887 fps | 96.6% |
| Vihtavuori N570 | 91.6 gr | 84% | 44,860 psi | 67% | 3018 fps | 96% |
| Winchester StaBALL HD | <<locked>> | 80% | 50,372 psi | 76% | 3068 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 50,908 psi | 76% | 2999 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 | Rhino Solid Shank. ADI AR 2218 delivers the highest muzzle velocity at 3,333 fps; across all powders the maximum-charge window runs from 2,064 fps to 3,333 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 1:12.5 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 | Rhino Solid Shank 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.