Load Specifications
Load data in caliber 7.21 Firebird with .287 | 160gr | Woodleigh PP SN 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-33.
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% | 60,075 psi | 90% | 3028 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 57,464 psi | 86% | 3104 fps | 99.2% |
| Accurate MAGPRO | <<locked>> | 82% | 59,611 psi | 89% | 3159 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 60,089 psi | 90% | 3150 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 60,234 psi | 90% | 3140 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 57,348 psi | 86% | 3225 fps | 99.7% |
| ADI AR 2225 | <<locked>> | 92% | 56,536 psi | 85% | 3107 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 60,263 psi | 90% | 3110 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 56,681 psi | 85% | 3081 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 58,943 psi | 88% | 3035 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 60,234 psi | 90% | 3120 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 59,466 psi | 89% | 3196 fps | 99.6% |
| Alliant Reloder-50 | <<locked>> | 96% | 60,147 psi | 90% | 3196 fps | 99.5% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 59,799 psi | 90% | 3110 fps | 99.7% |
| Bofors RP15 | <<locked>> | 86% | 59,959 psi | 90% | 3130 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 60,263 psi | 90% | 3153 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 56,681 psi | 85% | 3081 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 57,464 psi | 86% | 3094 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 58,262 psi | 87% | 3077 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 57,130 psi | 86% | 3061 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 56,420 psi | 85% | 3166 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,159 psi | 57% | 2005 fps | 100% |
| Hodgdon US 869 | <<locked>> | 98% | 58,015 psi | 87% | 3104 fps | 96% |
| IMR 4955 Enduron | <<locked>> | 82% | 57,885 psi | 87% | 3048 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 58,726 psi | 88% | 3136 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 56,739 psi | 85% | 3009 fps | 97.1% |
| IMR 8133 Enduron | <<locked>> | 96% | 59,205 psi | 89% | 3153 fps | 100% |
| Lovex D100 | <<locked>> | 92% | 58,755 psi | 88% | 3068 fps | 96.6% |
| Lovex S071 | <<locked>> | 88% | 58,552 psi | 88% | 3009 fps | 100% |
| Norma 217 | <<locked>> | 94% | 57,101 psi | 86% | 3114 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 56,376 psi | 85% | 3100 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 59,205 psi | 89% | 3081 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,291 psi | 59% | 2051 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 57,232 psi | 86% | 3146 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 56,217 psi | 84% | 3120 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 60,249 psi | 90% | 3104 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 58,755 psi | 88% | 3068 fps | 96.6% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 58,943 psi | 88% | 3107 fps | 99.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 59,886 psi | 90% | 3104 fps | 100% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 52,228 psi | 78% | 3012 fps | 96.7% |
| Vihtavuori 24N41 | <<locked>> | 96% | 58,566 psi | 88% | 3117 fps | 96.1% |
| Vihtavuori N165 | <<locked>> | 84% | 56,855 psi | 85% | 3002 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 56,724 psi | 85% | 3048 fps | 98.4% |
| Vihtavuori N560 | <<locked>> | 82% | 60,191 psi | 90% | 3166 fps | 100% |
| Vihtavuori N565 | <<locked>> | 86% | 57,899 psi | 87% | 3104 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 56,550 psi | 85% | 3127 fps | 99.9% |
| Vihtavuori N570 | <<locked>> | 90% | 58,247 psi | 87% | 3202 fps | 99.3% |
| Winchester StaBALL HD | <<locked>> | 82% | 56,855 psi | 85% | 3077 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 60,350 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% | 52,663 psi | 79% | 2923 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 42,757 psi | 64% | 2835 fps | 96% |
| Accurate MAGPRO | <<locked>> | 80% | 55,550 psi | 83% | 3094 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 52,272 psi | 78% | 3025 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 39,407 psi | 59% | 2769 fps | 98.7% |
| ADI AR 2218 | 92.7 gr | 84% | 39,262 psi | 59% | 2844 fps | 95.3% |
| ADI AR 2225 | <<locked>> | 80% | 36,869 psi | 55% | 2743 fps | 99.9% |
| Alliant Reloder-19 | <<locked>> | 80% | 56,449 psi | 85% | 3054 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 52,982 psi | 79% | 3022 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 51,648 psi | 77% | 2927 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 45,774 psi | 69% | 2894 fps | 100% |
| Alliant Reloder-33 | 92.2 gr | 82% | 40,944 psi | 61% | 2838 fps | 95.8% |
| Alliant Reloder-50 | <<locked>> | 86% | 41,539 psi | 62% | 2838 fps | 95.4% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 49,095 psi | 74% | 2927 fps | 98.4% |
| Bofors RP15 | <<locked>> | 80% | 49,356 psi | 74% | 2959 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 42,844 psi | 64% | 2848 fps | 99.3% |
| Bofors RP5 | <<locked>> | 80% | 52,982 psi | 79% | 3022 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 43,018 psi | 64% | 2844 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 80% | 54,273 psi | 81% | 3012 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 53,388 psi | 80% | 2999 fps | 99.9% |
| Hodgdon Retumbo | <<locked>> | 80% | 45,411 psi | 68% | 2976 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,689 psi | 43% | 1795 fps | 100% |
| Hodgdon US 869 | <<locked>> | 96% | 54,070 psi | 81% | 3038 fps | 95% |
| IMR 4955 Enduron | <<locked>> | 80% | 54,244 psi | 81% | 2989 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 51,213 psi | 77% | 3012 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 84% | 49,850 psi | 75% | 2887 fps | 95.5% |
| IMR 8133 Enduron | <<locked>> | 80% | 34,301 psi | 51% | 2657 fps | 96.9% |
| Lovex D100 | <<locked>> | 90% | 54,766 psi | 82% | 3002 fps | 95.7% |
| Lovex S071 | <<locked>> | 80% | 45,498 psi | 68% | 2802 fps | 100% |
| Norma 217 | <<locked>> | 80% | 34,983 psi | 52% | 2687 fps | 99% |
| Ramshot Grand | <<locked>> | 80% | 52,417 psi | 79% | 3035 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 47,355 psi | 71% | 2897 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,602 psi | 44% | 1841 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 45,368 psi | 68% | 2949 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 41,568 psi | 62% | 2844 fps | 98.1% |
| Rottweil R 905 | <<locked>> | 80% | 56,492 psi | 85% | 3051 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 54,766 psi | 82% | 3002 fps | 95.7% |
| SNPE Vectan SP 13 | <<locked>> | 90% | 41,771 psi | 63% | 2792 fps | 95.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 56,130 psi | 84% | 3045 fps | 100% |
| Vihtavuori 20N29 | <<locked>> | 98% | 48,704 psi | 73% | 2946 fps | 95.7% |
| Vihtavuori 24N41 | <<locked>> | 94% | 54,491 psi | 82% | 3048 fps | 95% |
| Vihtavuori N165 | <<locked>> | 80% | 49,922 psi | 75% | 2894 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 43,178 psi | 65% | 2792 fps | 95.1% |
| Vihtavuori N560 | <<locked>> | 80% | 56,101 psi | 84% | 3104 fps | 100% |
| Vihtavuori N565 | <<locked>> | 80% | 47,369 psi | 71% | 2923 fps | 99.5% |
| Vihtavuori N568 | <<locked>> | 80% | 42,467 psi | 64% | 2858 fps | 97.8% |
| Vihtavuori N570 | 86.5 gr | 80% | 40,553 psi | 61% | 2848 fps | 95.2% |
| Winchester StaBALL HD | <<locked>> | 80% | 52,852 psi | 79% | 3018 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 52,721 psi | 79% | 2953 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 .287 | 160gr | Woodleigh PP SN. ADI AR 2218 delivers the highest muzzle velocity at 3,225 fps; across all powders the maximum-charge window runs from 2,005 fps to 3,225 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 160.0 gr projectile in 0.287" calls for a 1:12.0 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-33 rank at the top here: for 7.21 Firebird with the .287 | 160gr | Woodleigh PP SN 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.