Load Specifications
Load data in caliber 7.21 Firebird with .284 | 175gr | Speer Magnum Tip Soft Point bullet and 40 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2218, Ramshot LRT 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>> | 82% | 59,756 psi | 90% | 2910 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 57,856 psi | 87% | 3005 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 82% | 59,640 psi | 89% | 3028 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 60,321 psi | 90% | 3025 fps | 100% |
| ADI AR 2218 | <<locked>> | 92% | 57,653 psi | 86% | 3120 fps | 100% |
| ADI AR 2225 | <<locked>> | 90% | 56,884 psi | 85% | 2992 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 60,176 psi | 90% | 3018 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 82% | 58,740 psi | 88% | 2910 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 60,365 psi | 90% | 3002 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 59,683 psi | 89% | 3084 fps | 99.9% |
| Alliant Reloder-50 | <<locked>> | 92% | 56,420 psi | 85% | 3028 fps | 99.5% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 59,117 psi | 89% | 2992 fps | 99.9% |
| Bofors RP15 | <<locked>> | 84% | 59,959 psi | 90% | 3015 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 60,234 psi | 90% | 3038 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 60,176 psi | 90% | 3018 fps | 100% |
| Hodgdon H1000 | <<locked>> | 86% | 57,377 psi | 86% | 2979 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 84% | 56,927 psi | 85% | 3051 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,305 psi | 57% | 1926 fps | 100% |
| Hodgdon US 869 | <<locked>> | 96% | 57,986 psi | 87% | 3005 fps | 97% |
| IMR 7828 SSC | <<locked>> | 82% | 58,610 psi | 88% | 3018 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 59,988 psi | 90% | 2959 fps | 98.5% |
| IMR 8133 Enduron | <<locked>> | 94% | 59,596 psi | 89% | 3041 fps | 100% |
| Lovex D100 | <<locked>> | 90% | 58,349 psi | 87% | 2963 fps | 97.5% |
| Lovex S071 | <<locked>> | 86% | 58,421 psi | 88% | 2894 fps | 100% |
| Norma 217 | <<locked>> | 92% | 57,682 psi | 86% | 3005 fps | 100% |
| Ramshot LRT | <<locked>> | 92% | 56,811 psi | 85% | 3045 fps | 96.9% |
| Ramshot Magnum | <<locked>> | 84% | 58,885 psi | 88% | 2963 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,479 psi | 59% | 1972 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 84% | 57,522 psi | 86% | 3028 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 86% | 56,391 psi | 85% | 3012 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 58,349 psi | 87% | 2963 fps | 97.5% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 59,132 psi | 89% | 3009 fps | 99.6% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 56,695 psi | 85% | 2989 fps | 98.4% |
| Vihtavuori 24N41 | <<locked>> | 94% | 58,566 psi | 88% | 3015 fps | 97% |
| Vihtavuori N165 | <<locked>> | 84% | 60,365 psi | 90% | 2940 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 60,205 psi | 90% | 2999 fps | 99.4% |
| Vihtavuori N565 | <<locked>> | 84% | 57,986 psi | 87% | 2995 fps | 100% |
| Vihtavuori N568 | <<locked>> | 86% | 56,579 psi | 85% | 3015 fps | 100% |
| Vihtavuori N570 | <<locked>> | 88% | 58,552 psi | 88% | 3094 fps | 99.7% |
| Winchester Supreme 780 | <<locked>> | 82% | 59,901 psi | 90% | 2949 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% | 55,898 psi | 84% | 2858 fps | 100% |
| Accurate 8700 | <<locked>> | 86% | 37,260 psi | 56% | 2618 fps | 95.1% |
| ADI AR 2213 | <<locked>> | 80% | 55,840 psi | 84% | 2972 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 42,453 psi | 64% | 2730 fps | 99.7% |
| ADI AR 2218 | 88.4 gr | 80% | 36,724 psi | 55% | 2684 fps | 95.4% |
| ADI AR 2225 | <<locked>> | 80% | 39,987 psi | 60% | 2707 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 56,507 psi | 85% | 2963 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 54,926 psi | 82% | 2861 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 49,313 psi | 74% | 2841 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 80% | 41,278 psi | 62% | 2749 fps | 97% |
| Alliant Reloder-50 | 92 gr | 82% | 39,117 psi | 59% | 2687 fps | 95.6% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 52,040 psi | 78% | 2877 fps | 99.4% |
| Bofors RP15 | <<locked>> | 80% | 52,504 psi | 79% | 2900 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 46,035 psi | 69% | 2805 fps | 99.9% |
| Bofors RP5 | <<locked>> | 80% | 56,507 psi | 85% | 2963 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 46,441 psi | 70% | 2805 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 49,284 psi | 74% | 2930 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,950 psi | 43% | 1726 fps | 100% |
| Hodgdon US 869 | <<locked>> | 92% | 50,444 psi | 76% | 2874 fps | 95.1% |
| IMR 7828 SSC | <<locked>> | 80% | 54,694 psi | 82% | 2959 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 80% | 46,180 psi | 69% | 2720 fps | 95.6% |
| IMR 8133 Enduron | <<locked>> | 80% | 37,188 psi | 56% | 2631 fps | 98.7% |
| Lovex D100 | <<locked>> | 86% | 50,749 psi | 76% | 2835 fps | 95.8% |
| Lovex S071 | <<locked>> | 80% | 48,370 psi | 73% | 2743 fps | 100% |
| Norma 217 | <<locked>> | 80% | 38,232 psi | 57% | 2661 fps | 99.9% |
| Ramshot LRT | 99.2 gr | 90% | 52,924 psi | 79% | 2976 fps | 96% |
| Ramshot Magnum | <<locked>> | 80% | 50,836 psi | 76% | 2844 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,776 psi | 45% | 1768 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 49,487 psi | 74% | 2907 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 45,179 psi | 68% | 2815 fps | 99.4% |
| Shooters World 50 BMG | <<locked>> | 86% | 50,749 psi | 76% | 2835 fps | 95.8% |
| SNPE Vectan SP 13 | <<locked>> | 86% | 39,291 psi | 59% | 2641 fps | 95.4% |
| Vihtavuori 20N29 | <<locked>> | 94% | 45,803 psi | 69% | 2795 fps | 95.9% |
| Vihtavuori 24N41 | <<locked>> | 90% | 50,807 psi | 76% | 2884 fps | 95.2% |
| Vihtavuori N165 | <<locked>> | 80% | 52,895 psi | 79% | 2831 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 46,093 psi | 69% | 2756 fps | 97% |
| Vihtavuori N565 | <<locked>> | 80% | 50,618 psi | 76% | 2874 fps | 100% |
| Vihtavuori N568 | <<locked>> | 80% | 45,788 psi | 69% | 2825 fps | 99.2% |
| Vihtavuori N570 | <<locked>> | 80% | 44,048 psi | 66% | 2825 fps | 97.4% |
| Winchester Supreme 780 | <<locked>> | 80% | 55,840 psi | 84% | 2890 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 40 powders for 7.21 Firebird loaded with the .284 | 175gr | Speer Magnum Tip Soft Point. ADI AR 2218 delivers the highest muzzle velocity at 3,120 fps; across all powders the maximum-charge window runs from 1,926 fps to 3,120 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 40 of the 40 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 175.0 gr projectile in 0.284" calls for a 1:12.5 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, Ramshot LRT, Alliant Reloder-50 rank at the top here: for 7.21 Firebird with the .284 | 175gr | Speer Magnum Tip Soft Point 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.