Load Specifications
Load data in caliber 7.21 Firebird with .284 | 156gr | Norma ORYX 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, 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% | 60,002 psi | 90% | 3061 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 57,406 psi | 86% | 3130 fps | 99.1% |
| Accurate MAGPRO | <<locked>> | 82% | 59,582 psi | 89% | 3189 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 59,959 psi | 90% | 3182 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 60,133 psi | 90% | 3169 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 57,217 psi | 86% | 3251 fps | 99.6% |
| ADI AR 2225 | <<locked>> | 92% | 56,405 psi | 85% | 3133 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 60,046 psi | 90% | 3143 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 56,594 psi | 85% | 3114 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 58,682 psi | 88% | 3061 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 60,046 psi | 90% | 3150 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 59,509 psi | 89% | 3225 fps | 99.6% |
| Alliant Reloder-50 | <<locked>> | 96% | 60,118 psi | 90% | 3222 fps | 99.4% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 59,727 psi | 90% | 3140 fps | 99.6% |
| Bofors RP15 | <<locked>> | 86% | 60,017 psi | 90% | 3166 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 60,002 psi | 90% | 3182 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 56,594 psi | 85% | 3114 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 57,246 psi | 86% | 3123 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 57,986 psi | 87% | 3104 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 57,087 psi | 86% | 3091 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 60,350 psi | 90% | 3255 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,130 psi | 57% | 2031 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 57,856 psi | 87% | 3077 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 58,610 psi | 88% | 3166 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 56,608 psi | 85% | 3038 fps | 96.9% |
| IMR 8133 Enduron | <<locked>> | 96% | 59,234 psi | 89% | 3182 fps | 100% |
| Lovex D100 | <<locked>> | 92% | 58,639 psi | 88% | 3091 fps | 96.4% |
| Lovex S071 | <<locked>> | 88% | 58,508 psi | 88% | 3041 fps | 100% |
| Norma 217 | <<locked>> | 94% | 56,927 psi | 85% | 3143 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 56,231 psi | 84% | 3127 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 59,117 psi | 89% | 3114 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,233 psi | 59% | 2077 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 57,116 psi | 86% | 3173 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 56,188 psi | 84% | 3153 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 82% | 60,191 psi | 90% | 3140 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 58,639 psi | 88% | 3091 fps | 96.4% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 58,769 psi | 88% | 3136 fps | 99% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 59,872 psi | 90% | 3133 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 60,365 psi | 90% | 3100 fps | 100% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 52,185 psi | 78% | 3038 fps | 96.5% |
| Vihtavuori N165 | <<locked>> | 84% | 56,753 psi | 85% | 3031 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 56,608 psi | 85% | 3077 fps | 98.2% |
| Vihtavuori N555 | <<locked>> | 82% | 60,205 psi | 90% | 3091 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 60,031 psi | 90% | 3196 fps | 100% |
| Vihtavuori N565 | <<locked>> | 86% | 57,870 psi | 87% | 3133 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 56,449 psi | 85% | 3153 fps | 99.8% |
| Vihtavuori N570 | <<locked>> | 90% | 58,233 psi | 87% | 3228 fps | 99.2% |
| Winchester StaBALL HD | <<locked>> | 82% | 56,739 psi | 85% | 3107 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 82% | 56,333 psi | 84% | 3041 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% | 52,489 psi | 79% | 2953 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 42,743 psi | 64% | 2858 fps | 95.8% |
| Accurate MAGPRO | <<locked>> | 80% | 55,419 psi | 83% | 3123 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 80% | 52,069 psi | 78% | 3054 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 80% | 39,276 psi | 59% | 2792 fps | 98.6% |
| ADI AR 2218 | 96.3 gr | 86% | 42,206 psi | 63% | 2943 fps | 96.3% |
| ADI AR 2225 | <<locked>> | 80% | 36,709 psi | 55% | 2766 fps | 99.8% |
| Alliant Reloder-19 | <<locked>> | 80% | 56,304 psi | 84% | 3084 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 52,794 psi | 79% | 3051 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 51,517 psi | 77% | 2959 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 45,774 psi | 69% | 2923 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 82% | 40,770 psi | 61% | 2858 fps | 95.5% |
| Alliant Reloder-50 | 97.8 gr | 86% | 41,423 psi | 62% | 2861 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 49,008 psi | 73% | 2953 fps | 98.2% |
| Bofors RP15 | <<locked>> | 80% | 49,211 psi | 74% | 2986 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 42,714 psi | 64% | 2871 fps | 99.2% |
| Bofors RP5 | <<locked>> | 80% | 52,794 psi | 79% | 3051 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 42,975 psi | 64% | 2874 fps | 99.6% |
| Hodgdon H4831 | <<locked>> | 80% | 54,244 psi | 81% | 3045 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 53,214 psi | 80% | 3028 fps | 99.8% |
| Hodgdon Retumbo | <<locked>> | 80% | 45,223 psi | 68% | 3002 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,645 psi | 43% | 1821 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 54,273 psi | 81% | 3018 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 51,010 psi | 76% | 3041 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 84% | 49,821 psi | 75% | 2913 fps | 95.3% |
| IMR 8133 Enduron | <<locked>> | 80% | 34,185 psi | 51% | 2680 fps | 96.6% |
| Lovex D100 | <<locked>> | 90% | 54,520 psi | 82% | 3022 fps | 95.5% |
| Lovex S071 | <<locked>> | 80% | 45,426 psi | 68% | 2831 fps | 100% |
| Norma 217 | <<locked>> | 80% | 34,853 psi | 52% | 2710 fps | 98.8% |
| Ramshot Grand | <<locked>> | 80% | 52,330 psi | 78% | 3064 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 47,253 psi | 71% | 2923 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,559 psi | 44% | 1864 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 45,194 psi | 68% | 2972 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 41,568 psi | 62% | 2867 fps | 97.9% |
| Rottweil R 905 | <<locked>> | 80% | 56,333 psi | 84% | 3081 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 54,520 psi | 82% | 3022 fps | 95.5% |
| SNPE Vectan SP 13 | <<locked>> | 90% | 41,669 psi | 62% | 2815 fps | 95% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 55,985 psi | 84% | 3074 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 56,420 psi | 85% | 3041 fps | 100% |
| Vihtavuori 20N29 | <<locked>> | 98% | 48,530 psi | 73% | 2969 fps | 95.5% |
| Vihtavuori N165 | <<locked>> | 80% | 49,763 psi | 75% | 2920 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 46,166 psi | 69% | 2884 fps | 95.9% |
| Vihtavuori N555 | <<locked>> | 80% | 56,565 psi | 85% | 3041 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 56,028 psi | 84% | 3133 fps | 100% |
| Vihtavuori N565 | <<locked>> | 80% | 47,166 psi | 71% | 2946 fps | 99.4% |
| Vihtavuori N568 | <<locked>> | 80% | 42,235 psi | 63% | 2881 fps | 97.5% |
| Vihtavuori N570 | 90 gr | 82% | 43,540 psi | 65% | 2943 fps | 96% |
| Winchester StaBALL HD | <<locked>> | 80% | 52,794 psi | 79% | 3051 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 52,504 psi | 79% | 2979 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 49 powders for 7.21 Firebird loaded with the .284 | 156gr | Norma ORYX. Hodgdon Retumbo delivers the highest muzzle velocity at 3,255 fps; across all powders the maximum-charge window runs from 2,031 fps to 3,255 fps. Accurate 8700 gives the best case fill at 100 %, and 49 of the 49 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 156.0 gr projectile in 0.284" calls for a 1:13.5 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 | 156gr | Norma ORYX 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.