Load Specifications
Load data in caliber 7.21 Firebird with .284 | 170gr | Geco SOFTPOINT bullet and 42 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 Ramshot LRT.
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% | 59,030 psi | 88% | 2940 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 57,072 psi | 86% | 3025 fps | 99.5% |
| ADI AR 2213 | <<locked>> | 82% | 59,074 psi | 89% | 3058 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 59,596 psi | 89% | 3051 fps | 100% |
| ADI AR 2218 | <<locked>> | 92% | 56,855 psi | 85% | 3143 fps | 99.9% |
| ADI AR 2225 | <<locked>> | 92% | 60,118 psi | 90% | 3074 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 59,669 psi | 89% | 3048 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 82% | 58,059 psi | 87% | 2943 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 59,509 psi | 89% | 3028 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 58,943 psi | 88% | 3110 fps | 99.8% |
| Alliant Reloder-50 | <<locked>> | 94% | 59,756 psi | 90% | 3114 fps | 99.7% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 58,552 psi | 88% | 3018 fps | 99.8% |
| Bofors RP15 | <<locked>> | 84% | 59,248 psi | 89% | 3041 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 59,524 psi | 89% | 3064 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 59,669 psi | 89% | 3048 fps | 100% |
| Hodgdon H1000 | <<locked>> | 86% | 56,724 psi | 85% | 3005 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 59,944 psi | 90% | 3025 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 60,147 psi | 90% | 3136 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,276 psi | 57% | 1955 fps | 100% |
| Hodgdon US 869 | <<locked>> | 96% | 57,319 psi | 86% | 3025 fps | 96.6% |
| IMR 7828 SSC | <<locked>> | 82% | 57,841 psi | 87% | 3045 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 59,263 psi | 89% | 2982 fps | 98.2% |
| IMR 8133 Enduron | <<locked>> | 94% | 59,001 psi | 88% | 3068 fps | 100% |
| Lovex D100 | <<locked>> | 90% | 57,754 psi | 87% | 2986 fps | 97.1% |
| Lovex S071 | <<locked>> | 86% | 57,769 psi | 87% | 2920 fps | 100% |
| Norma 217 | <<locked>> | 92% | 56,884 psi | 85% | 3028 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 59,770 psi | 90% | 3068 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 60,249 psi | 90% | 3133 fps | 97.3% |
| Ramshot Magnum | <<locked>> | 84% | 58,189 psi | 87% | 2989 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,421 psi | 59% | 2001 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 84% | 56,695 psi | 85% | 3054 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 59,915 psi | 90% | 3100 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 57,754 psi | 87% | 2986 fps | 97.1% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 58,407 psi | 88% | 3028 fps | 99.4% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 55,869 psi | 84% | 3009 fps | 98.1% |
| Vihtavuori 24N41 | <<locked>> | 94% | 57,725 psi | 87% | 3035 fps | 96.6% |
| Vihtavuori N165 | <<locked>> | 84% | 59,654 psi | 89% | 2966 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 59,524 psi | 89% | 3022 fps | 99.2% |
| Vihtavuori N565 | <<locked>> | 84% | 57,174 psi | 86% | 3018 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 59,901 psi | 90% | 3104 fps | 100% |
| Vihtavuori N570 | <<locked>> | 88% | 57,754 psi | 87% | 3114 fps | 99.6% |
| Winchester Supreme 780 | <<locked>> | 82% | 59,205 psi | 89% | 2976 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% | 55,419 psi | 83% | 2887 fps | 100% |
| Accurate 8700 | <<locked>> | 88% | 39,523 psi | 59% | 2697 fps | 95.6% |
| ADI AR 2213 | <<locked>> | 80% | 55,158 psi | 83% | 2995 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 41,858 psi | 63% | 2753 fps | 99.6% |
| ADI AR 2218 | 91.3 gr | 82% | 38,870 psi | 58% | 2772 fps | 96% |
| ADI AR 2225 | <<locked>> | 80% | 39,392 psi | 59% | 2730 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 55,825 psi | 84% | 2989 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 54,317 psi | 81% | 2890 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 48,660 psi | 73% | 2864 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 80% | 40,567 psi | 61% | 2762 fps | 96.4% |
| Alliant Reloder-50 | <<locked>> | 82% | 38,406 psi | 58% | 2697 fps | 95% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 51,430 psi | 77% | 2900 fps | 99.2% |
| Bofors RP15 | <<locked>> | 80% | 51,895 psi | 78% | 2927 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 45,571 psi | 68% | 2831 fps | 99.9% |
| Bofors RP5 | <<locked>> | 80% | 55,825 psi | 84% | 2989 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 45,803 psi | 69% | 2825 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 80% | 56,101 psi | 84% | 2969 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 48,544 psi | 73% | 2953 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,863 psi | 43% | 1752 fps | 100% |
| Hodgdon US 869 | <<locked>> | 94% | 53,447 psi | 80% | 2959 fps | 95.6% |
| IMR 7828 SSC | <<locked>> | 80% | 53,998 psi | 81% | 2986 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 80% | 45,716 psi | 69% | 2743 fps | 95.1% |
| IMR 8133 Enduron | <<locked>> | 80% | 36,651 psi | 55% | 2651 fps | 98.3% |
| Lovex D100 | <<locked>> | 86% | 50,140 psi | 75% | 2854 fps | 95.3% |
| Lovex S071 | <<locked>> | 80% | 47,863 psi | 72% | 2769 fps | 100% |
| Norma 217 | <<locked>> | 80% | 37,637 psi | 56% | 2680 fps | 99.8% |
| Ramshot Grand | <<locked>> | 80% | 55,680 psi | 83% | 3009 fps | 100% |
| Ramshot LRT | 100 gr | 90% | 52,127 psi | 78% | 2992 fps | 95.4% |
| Ramshot Magnum | <<locked>> | 80% | 50,285 psi | 75% | 2871 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,675 psi | 44% | 1791 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 48,646 psi | 73% | 2930 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 44,425 psi | 67% | 2835 fps | 99.1% |
| Shooters World 50 BMG | <<locked>> | 86% | 50,140 psi | 75% | 2854 fps | 95.3% |
| SNPE Vectan SP 13 | <<locked>> | 88% | 41,481 psi | 62% | 2720 fps | 95.9% |
| Vihtavuori 20N29 | <<locked>> | 94% | 45,179 psi | 68% | 2812 fps | 95.4% |
| Vihtavuori 24N41 | <<locked>> | 92% | 53,780 psi | 81% | 2969 fps | 95.7% |
| Vihtavuori N165 | <<locked>> | 80% | 52,489 psi | 79% | 2861 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 45,498 psi | 68% | 2776 fps | 96.6% |
| Vihtavuori N565 | <<locked>> | 80% | 49,951 psi | 75% | 2897 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 80% | 45,078 psi | 68% | 2841 fps | 98.9% |
| Vihtavuori N570 | 87.3 gr | 80% | 43,352 psi | 65% | 2841 fps | 96.9% |
| Winchester Supreme 780 | <<locked>> | 80% | 55,376 psi | 83% | 2920 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 42 powders for 7.21 Firebird loaded with the .284 | 170gr | Geco SOFTPOINT. ADI AR 2218 delivers the highest muzzle velocity at 3,143 fps; across all powders the maximum-charge window runs from 1,955 fps to 3,143 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 42 of the 42 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 170.0 gr projectile in 0.284" calls for a 1:13.0 twist; slower twists will usually not stabilise this weight. Hodgdon TrailBoss, ReloadSwiss RS 14, Vihtavuori 20N29 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, Ramshot LRT rank at the top here: for 7.21 Firebird with the .284 | 170gr | 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.