Load Specifications
Load data in caliber 7.21 Firebird with .284 | 165gr | Geco SOFTPOINT bullet and 45 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>> | 82% | 58,189 psi | 87% | 2966 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 60,321 psi | 90% | 3110 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 82% | 58,001 psi | 87% | 3081 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 58,537 psi | 88% | 3074 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 60,147 psi | 90% | 3232 fps | 100% |
| ADI AR 2225 | <<locked>> | 92% | 58,929 psi | 88% | 3097 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 58,581 psi | 88% | 3071 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 82% | 57,029 psi | 85% | 2966 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 58,523 psi | 88% | 3054 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 57,740 psi | 87% | 3127 fps | 99.6% |
| Alliant Reloder-50 | <<locked>> | 94% | 58,653 psi | 88% | 3130 fps | 99.5% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 57,740 psi | 87% | 3041 fps | 99.7% |
| Bofors RP15 | <<locked>> | 84% | 58,349 psi | 87% | 3068 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 58,494 psi | 88% | 3087 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 58,581 psi | 88% | 3071 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 59,770 psi | 90% | 3087 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 60,075 psi | 90% | 3068 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 58,929 psi | 88% | 3048 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 58,987 psi | 88% | 3159 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,305 psi | 57% | 1982 fps | 100% |
| Hodgdon US 869 | <<locked>> | 96% | 56,333 psi | 84% | 3041 fps | 96.1% |
| IMR 4955 Enduron | <<locked>> | 82% | 59,509 psi | 89% | 3035 fps | 100% |
| IMR 7828 SSC | <<locked>> | 82% | 56,956 psi | 85% | 3071 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 58,479 psi | 88% | 3002 fps | 97.8% |
| IMR 8133 Enduron | <<locked>> | 94% | 57,870 psi | 87% | 3091 fps | 100% |
| Lovex D100 | <<locked>> | 90% | 56,768 psi | 85% | 3002 fps | 96.6% |
| Lovex S071 | <<locked>> | 86% | 56,913 psi | 85% | 2946 fps | 100% |
| Norma 217 | <<locked>> | 94% | 59,683 psi | 89% | 3110 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 58,711 psi | 88% | 3094 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 59,045 psi | 89% | 3146 fps | 96.8% |
| Ramshot Magnum | <<locked>> | 84% | 57,174 psi | 86% | 3015 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,436 psi | 59% | 2028 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 59,988 psi | 90% | 3143 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 58,711 psi | 88% | 3120 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 56,768 psi | 85% | 3002 fps | 96.6% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 57,435 psi | 86% | 3051 fps | 99.2% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 54,795 psi | 82% | 3022 fps | 97.6% |
| Vihtavuori 24N41 | <<locked>> | 94% | 56,826 psi | 85% | 3051 fps | 96.1% |
| Vihtavuori N165 | <<locked>> | 84% | 58,813 psi | 88% | 2992 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 58,566 psi | 88% | 3045 fps | 98.9% |
| Vihtavuori N565 | <<locked>> | 86% | 60,234 psi | 90% | 3100 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 58,784 psi | 88% | 3120 fps | 100% |
| Vihtavuori N570 | <<locked>> | 88% | 56,608 psi | 85% | 3133 fps | 99.3% |
| Winchester StaBALL HD | <<locked>> | 82% | 59,466 psi | 89% | 3068 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 82% | 58,392 psi | 88% | 3002 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% | 54,476 psi | 82% | 2910 fps | 100% |
| Accurate 8700 | <<locked>> | 90% | 41,669 psi | 62% | 2776 fps | 96.1% |
| ADI AR 2213 | <<locked>> | 80% | 54,143 psi | 81% | 3018 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 41,089 psi | 62% | 2769 fps | 99.3% |
| ADI AR 2218 | 91.7 gr | 82% | 38,101 psi | 57% | 2782 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 80% | 38,566 psi | 58% | 2746 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 54,853 psi | 82% | 3012 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 53,548 psi | 80% | 2917 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 47,834 psi | 72% | 2890 fps | 100% |
| Alliant Reloder-33 | 91.1 gr | 80% | 39,740 psi | 60% | 2776 fps | 95.8% |
| Alliant Reloder-50 | <<locked>> | 84% | 40,495 psi | 61% | 2779 fps | 95.5% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 50,720 psi | 76% | 2923 fps | 98.9% |
| Bofors RP15 | <<locked>> | 80% | 51,140 psi | 77% | 2953 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 44,643 psi | 67% | 2848 fps | 99.7% |
| Bofors RP5 | <<locked>> | 80% | 54,853 psi | 82% | 3012 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 44,817 psi | 67% | 2844 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 80% | 56,202 psi | 84% | 3005 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 80% | 55,143 psi | 83% | 2992 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 47,543 psi | 71% | 2972 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,790 psi | 43% | 1775 fps | 100% |
| Hodgdon US 869 | <<locked>> | 94% | 52,533 psi | 79% | 2976 fps | 95.1% |
| IMR 4955 Enduron | <<locked>> | 80% | 56,014 psi | 84% | 2979 fps | 100% |
| IMR 7828 SSC | <<locked>> | 80% | 53,142 psi | 80% | 3009 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 82% | 48,240 psi | 72% | 2825 fps | 95.5% |
| IMR 8133 Enduron | <<locked>> | 80% | 35,940 psi | 54% | 2667 fps | 97.9% |
| Lovex D100 | <<locked>> | 88% | 52,794 psi | 79% | 2933 fps | 95.7% |
| Lovex S071 | <<locked>> | 80% | 47,036 psi | 71% | 2792 fps | 100% |
| Norma 217 | <<locked>> | 80% | 36,738 psi | 55% | 2694 fps | 99.5% |
| Ramshot Grand | <<locked>> | 80% | 54,520 psi | 82% | 3028 fps | 100% |
| Ramshot LRT | <<locked>> | 92% | 55,013 psi | 82% | 3077 fps | 95.9% |
| Ramshot Magnum | <<locked>> | 80% | 49,371 psi | 74% | 2894 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,733 psi | 45% | 1821 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 47,616 psi | 71% | 2949 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 43,540 psi | 65% | 2851 fps | 98.8% |
| Shooters World 50 BMG | <<locked>> | 88% | 52,794 psi | 79% | 2933 fps | 95.7% |
| SNPE Vectan SP 13 | <<locked>> | 88% | 40,669 psi | 61% | 2733 fps | 95.3% |
| Vihtavuori 20N29 | <<locked>> | 96% | 47,471 psi | 71% | 2890 fps | 95.8% |
| Vihtavuori 24N41 | <<locked>> | 92% | 52,924 psi | 79% | 2986 fps | 95.1% |
| Vihtavuori N165 | <<locked>> | 80% | 51,590 psi | 77% | 2884 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 44,802 psi | 67% | 2792 fps | 96.1% |
| Vihtavuori N565 | <<locked>> | 80% | 49,153 psi | 74% | 2920 fps | 99.8% |
| Vihtavuori N568 | <<locked>> | 80% | 44,251 psi | 66% | 2861 fps | 98.5% |
| Vihtavuori N570 | 87.7 gr | 80% | 42,482 psi | 64% | 2858 fps | 96.3% |
| Winchester StaBALL HD | <<locked>> | 80% | 55,376 psi | 83% | 3012 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 54,433 psi | 82% | 2943 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 45 powders for 7.21 Firebird loaded with the .284 | 165gr | Geco SOFTPOINT. ADI AR 2218 delivers the highest muzzle velocity at 3,232 fps; across all powders the maximum-charge window runs from 1,982 fps to 3,232 fps. Accurate 8700 gives the best case fill at 100 %, and 45 of the 45 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 165.0 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-33 rank at the top here: for 7.21 Firebird with the .284 | 165gr | Geco SOFTPOINT 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.