Load Specifications
Load data in caliber 7.21 Firebird with .284 | 160gr | Rhino Solid Shank bullet and 51 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2218, Vihtavuori N570 and Alliant Reloder-50.
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% | 59,959 psi | 90% | 3031 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 57,203 psi | 86% | 3100 fps | 99.2% |
| Accurate MAGPRO | <<locked>> | 82% | 59,524 psi | 89% | 3159 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 59,973 psi | 90% | 3153 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 59,959 psi | 90% | 3136 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 57,058 psi | 86% | 3222 fps | 99.7% |
| ADI AR 2225 | <<locked>> | 94% | 60,365 psi | 90% | 3159 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 60,002 psi | 90% | 3107 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 56,550 psi | 85% | 3081 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 58,610 psi | 88% | 3028 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 60,147 psi | 90% | 3120 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 59,176 psi | 89% | 3189 fps | 99.6% |
| Alliant Reloder-50 | <<locked>> | 96% | 59,872 psi | 90% | 3189 fps | 99.4% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 59,567 psi | 89% | 3107 fps | 99.7% |
| Bofors RP15 | <<locked>> | 86% | 59,857 psi | 90% | 3130 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 59,959 psi | 90% | 3150 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 56,550 psi | 85% | 3081 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 57,203 psi | 86% | 3091 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 57,986 psi | 87% | 3071 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 57,058 psi | 86% | 3058 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 60,278 psi | 90% | 3225 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,145 psi | 57% | 2001 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 57,769 psi | 87% | 3045 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 58,624 psi | 88% | 3133 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 60,365 psi | 90% | 3064 fps | 97.7% |
| IMR 8133 Enduron | <<locked>> | 96% | 59,132 psi | 89% | 3150 fps | 100% |
| Lovex D100 | <<locked>> | 92% | 58,508 psi | 88% | 3061 fps | 96.6% |
| Lovex S071 | <<locked>> | 88% | 58,436 psi | 88% | 3009 fps | 100% |
| Norma 217 | <<locked>> | 94% | 56,971 psi | 85% | 3114 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 56,246 psi | 84% | 3097 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 58,900 psi | 88% | 3077 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,276 psi | 59% | 2051 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 56,942 psi | 85% | 3140 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 56,130 psi | 84% | 3120 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 60,365 psi | 90% | 3087 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 60,133 psi | 90% | 3104 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 58,508 psi | 88% | 3061 fps | 96.6% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 58,682 psi | 88% | 3104 fps | 99.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 59,770 psi | 90% | 3100 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 60,336 psi | 90% | 3068 fps | 100% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 51,996 psi | 78% | 3012 fps | 96.6% |
| Vihtavuori 24N41 | <<locked>> | 96% | 58,363 psi | 87% | 3114 fps | 96% |
| Vihtavuori N165 | <<locked>> | 84% | 56,768 psi | 85% | 3002 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 56,463 psi | 85% | 3045 fps | 98.3% |
| Vihtavuori N555 | <<locked>> | 82% | 60,292 psi | 90% | 3061 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 59,872 psi | 90% | 3163 fps | 100% |
| Vihtavuori N565 | <<locked>> | 86% | 57,798 psi | 87% | 3104 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 56,289 psi | 84% | 3123 fps | 99.9% |
| Vihtavuori N570 | <<locked>> | 90% | 58,131 psi | 87% | 3199 fps | 99.3% |
| Winchester StaBALL HD | <<locked>> | 82% | 56,695 psi | 85% | 3074 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 60,263 psi | 90% | 3068 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% | 52,576 psi | 79% | 2923 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 42,554 psi | 64% | 2831 fps | 96% |
| Accurate MAGPRO | <<locked>> | 80% | 55,434 psi | 83% | 3094 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 52,141 psi | 78% | 3025 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 39,320 psi | 59% | 2766 fps | 98.7% |
| ADI AR 2218 | 92.5 gr | 84% | 39,189 psi | 59% | 2841 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 80% | 36,637 psi | 55% | 2740 fps | 99.8% |
| Alliant Reloder-19 | <<locked>> | 80% | 56,362 psi | 84% | 3051 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 52,852 psi | 79% | 3022 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 51,547 psi | 77% | 2927 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 45,672 psi | 68% | 2890 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 82% | 40,727 psi | 61% | 2835 fps | 95.8% |
| Alliant Reloder-50 | 96.1 gr | 86% | 41,307 psi | 62% | 2838 fps | 95.4% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 49,008 psi | 73% | 2927 fps | 98.4% |
| Bofors RP15 | <<locked>> | 80% | 49,226 psi | 74% | 2956 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 42,757 psi | 64% | 2848 fps | 99.3% |
| Bofors RP5 | <<locked>> | 80% | 52,852 psi | 79% | 3022 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 42,902 psi | 64% | 2844 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 80% | 54,186 psi | 81% | 3012 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 53,301 psi | 80% | 2995 fps | 99.9% |
| Hodgdon Retumbo | <<locked>> | 80% | 45,121 psi | 68% | 2969 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,776 psi | 43% | 1798 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 54,157 psi | 81% | 2986 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 50,937 psi | 76% | 3009 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 84% | 49,806 psi | 75% | 2884 fps | 95.5% |
| IMR 8133 Enduron | <<locked>> | 80% | 34,214 psi | 51% | 2657 fps | 96.9% |
| Lovex D100 | <<locked>> | 90% | 54,505 psi | 82% | 2995 fps | 95.6% |
| Lovex S071 | <<locked>> | 80% | 45,397 psi | 68% | 2799 fps | 100% |
| Norma 217 | <<locked>> | 80% | 34,853 psi | 52% | 2684 fps | 98.9% |
| Ramshot Grand | <<locked>> | 80% | 52,301 psi | 78% | 3035 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 47,239 psi | 71% | 2897 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,559 psi | 44% | 1837 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 45,223 psi | 68% | 2946 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 41,495 psi | 62% | 2841 fps | 98% |
| Rottweil R 904 | <<locked>> | 80% | 56,681 psi | 85% | 3031 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 56,202 psi | 84% | 3045 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 54,505 psi | 82% | 2995 fps | 95.6% |
| SNPE Vectan SP 13 | <<locked>> | 90% | 41,553 psi | 62% | 2785 fps | 95.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 55,854 psi | 84% | 3041 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 56,492 psi | 85% | 3009 fps | 100% |
| Vihtavuori 20N29 | <<locked>> | 98% | 48,472 psi | 73% | 2943 fps | 95.7% |
| Vihtavuori 24N41 | <<locked>> | 94% | 54,273 psi | 81% | 3041 fps | 95% |
| Vihtavuori N165 | <<locked>> | 80% | 49,806 psi | 75% | 2894 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 43,091 psi | 65% | 2792 fps | 95.1% |
| Vihtavuori N555 | <<locked>> | 80% | 56,594 psi | 85% | 3009 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 55,999 psi | 84% | 3100 fps | 100% |
| Vihtavuori N565 | <<locked>> | 80% | 47,108 psi | 71% | 2920 fps | 99.5% |
| Vihtavuori N568 | <<locked>> | 80% | 42,221 psi | 63% | 2854 fps | 97.7% |
| Vihtavuori N570 | 86.3 gr | 80% | 40,451 psi | 61% | 2844 fps | 95.1% |
| Winchester StaBALL HD | <<locked>> | 80% | 52,707 psi | 79% | 3018 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 52,605 psi | 79% | 2949 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 51 powders for 7.21 Firebird loaded with the .284 | 160gr | Rhino Solid Shank. Hodgdon Retumbo delivers the highest muzzle velocity at 3,225 fps; across all powders the maximum-charge window runs from 2,001 fps to 3,225 fps. Accurate 8700 gives the best case fill at 100 %, and 51 of the 51 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 160.0 gr projectile in 0.284" calls for a 1:11.5 twist; slower twists will usually not stabilise this weight. Accurate 8700, Hodgdon TrailBoss, ReloadSwiss RS 14 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, Vihtavuori N570, Alliant Reloder-50 rank at the top here: for 7.21 Firebird with the .284 | 160gr | Rhino Solid Shank they combine a high case fill with complete burn and sit in the upper velocity band. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.