Load Specifications
Load data in caliber 7.21 Firebird with .284 | 162gr | RWS Kegelspitz 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-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% | 57,566 psi | 86% | 2979 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 59,205 psi | 89% | 3117 fps | 99.5% |
| ADI AR 2213 | <<locked>> | 82% | 57,305 psi | 86% | 3094 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 57,551 psi | 86% | 3084 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 58,987 psi | 88% | 3238 fps | 99.9% |
| ADI AR 2225 | <<locked>> | 92% | 58,073 psi | 87% | 3107 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 57,914 psi | 87% | 3084 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 60,046 psi | 90% | 3031 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 57,783 psi | 87% | 3068 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 56,869 psi | 85% | 3133 fps | 99.5% |
| Alliant Reloder-50 | <<locked>> | 94% | 57,551 psi | 86% | 3133 fps | 99.3% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 57,159 psi | 86% | 3054 fps | 99.6% |
| Bofors RP15 | <<locked>> | 84% | 57,493 psi | 86% | 3081 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 57,769 psi | 87% | 3100 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 57,914 psi | 87% | 3084 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 58,972 psi | 88% | 3100 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 59,422 psi | 89% | 3081 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 58,291 psi | 87% | 3061 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 58,131 psi | 87% | 3173 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,290 psi | 57% | 1998 fps | 100% |
| Hodgdon US 869 | <<locked>> | 98% | 59,596 psi | 89% | 3117 fps | 96.6% |
| IMR 4955 Enduron | <<locked>> | 82% | 58,972 psi | 88% | 3051 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 60,017 psi | 90% | 3140 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 57,914 psi | 87% | 3015 fps | 97.5% |
| IMR 8133 Enduron | <<locked>> | 94% | 56,884 psi | 85% | 3100 fps | 100% |
| Lovex D100 | <<locked>> | 92% | 60,104 psi | 90% | 3074 fps | 97.1% |
| Lovex S071 | <<locked>> | 88% | 59,799 psi | 90% | 3012 fps | 100% |
| Norma 217 | <<locked>> | 94% | 58,827 psi | 88% | 3120 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 57,943 psi | 87% | 3104 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 58,233 psi | 87% | 3156 fps | 96.4% |
| Ramshot Magnum | <<locked>> | 84% | 56,434 psi | 85% | 3028 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,421 psi | 59% | 2044 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 58,885 psi | 88% | 3150 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 57,885 psi | 87% | 3130 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 60,104 psi | 90% | 3074 fps | 97.1% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 56,492 psi | 85% | 3054 fps | 98.9% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 53,809 psi | 81% | 3025 fps | 97.2% |
| Vihtavuori 24N41 | <<locked>> | 96% | 60,002 psi | 90% | 3127 fps | 96.6% |
| Vihtavuori N165 | <<locked>> | 84% | 58,175 psi | 87% | 3005 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 57,928 psi | 87% | 3054 fps | 98.7% |
| Vihtavuori N565 | <<locked>> | 86% | 59,321 psi | 89% | 3110 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 58,001 psi | 87% | 3133 fps | 100% |
| Vihtavuori N570 | <<locked>> | 90% | 59,930 psi | 90% | 3209 fps | 99.6% |
| Winchester StaBALL HD | <<locked>> | 82% | 58,610 psi | 88% | 3081 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 82% | 57,566 psi | 86% | 3012 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% | 53,838 psi | 81% | 2927 fps | 100% |
| Accurate 8700 | <<locked>> | 90% | 40,973 psi | 61% | 2782 fps | 95.6% |
| ADI AR 2213 | <<locked>> | 80% | 53,476 psi | 80% | 3028 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 40,495 psi | 61% | 2776 fps | 99.1% |
| ADI AR 2218 | 93.9 gr | 84% | 40,393 psi | 61% | 2858 fps | 96% |
| ADI AR 2225 | <<locked>> | 80% | 37,840 psi | 57% | 2749 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 54,172 psi | 81% | 3025 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 52,721 psi | 79% | 2927 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 47,021 psi | 70% | 2897 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 80% | 39,088 psi | 59% | 2779 fps | 95.3% |
| Alliant Reloder-50 | 95.4 gr | 84% | 39,813 psi | 60% | 2782 fps | 95% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 50,038 psi | 75% | 2930 fps | 98.7% |
| Bofors RP15 | <<locked>> | 80% | 50,517 psi | 76% | 2963 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 44,005 psi | 66% | 2854 fps | 99.5% |
| Bofors RP5 | <<locked>> | 80% | 54,172 psi | 81% | 3025 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 44,193 psi | 66% | 2854 fps | 99.8% |
| Hodgdon H4831 | <<locked>> | 80% | 55,434 psi | 83% | 3015 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 80% | 54,534 psi | 82% | 3002 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 46,644 psi | 70% | 2982 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,790 psi | 43% | 1791 fps | 100% |
| Hodgdon US 869 | <<locked>> | 96% | 55,390 psi | 83% | 3045 fps | 95.6% |
| IMR 4955 Enduron | <<locked>> | 80% | 55,317 psi | 83% | 2992 fps | 100% |
| IMR 7828 SSC | <<locked>> | 80% | 52,301 psi | 78% | 3015 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 82% | 47,572 psi | 71% | 2828 fps | 95.1% |
| IMR 8133 Enduron | <<locked>> | 80% | 35,259 psi | 53% | 2667 fps | 97.5% |
| Lovex D100 | <<locked>> | 88% | 52,156 psi | 78% | 2943 fps | 95.3% |
| Lovex S071 | <<locked>> | 80% | 46,470 psi | 70% | 2805 fps | 100% |
| Norma 217 | <<locked>> | 80% | 36,114 psi | 54% | 2697 fps | 99.3% |
| Ramshot Grand | <<locked>> | 80% | 53,751 psi | 81% | 3041 fps | 100% |
| Ramshot LRT | <<locked>> | 92% | 54,056 psi | 81% | 3084 fps | 95.4% |
| Ramshot Magnum | <<locked>> | 80% | 48,559 psi | 73% | 2900 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,573 psi | 44% | 1831 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 46,833 psi | 70% | 2956 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 42,859 psi | 64% | 2854 fps | 98.5% |
| Shooters World 50 BMG | <<locked>> | 88% | 52,156 psi | 78% | 2943 fps | 95.3% |
| SNPE Vectan SP 13 | <<locked>> | 90% | 42,888 psi | 64% | 2802 fps | 95.9% |
| Vihtavuori 20N29 | <<locked>> | 96% | 46,586 psi | 70% | 2890 fps | 95.3% |
| Vihtavuori 24N41 | <<locked>> | 94% | 55,883 psi | 84% | 3058 fps | 95.6% |
| Vihtavuori N165 | <<locked>> | 80% | 51,010 psi | 76% | 2897 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 44,135 psi | 66% | 2799 fps | 95.7% |
| Vihtavuori N565 | <<locked>> | 80% | 48,385 psi | 73% | 2927 fps | 99.7% |
| Vihtavuori N568 | <<locked>> | 80% | 43,598 psi | 65% | 2867 fps | 98.2% |
| Vihtavuori N570 | 87.6 gr | 80% | 41,698 psi | 63% | 2861 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 80% | 54,375 psi | 82% | 3022 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 53,853 psi | 81% | 2956 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 46 powders for 7.21 Firebird loaded with the .284 | 162gr | RWS Kegelspitz. ADI AR 2218 delivers the highest muzzle velocity at 3,238 fps; across all powders the maximum-charge window runs from 1,998 fps to 3,238 fps. Accurate 8700 gives the best case fill at 100 %, and 46 of the 46 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 162.0 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 | 162gr | RWS Kegelspitz they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon 50BMG burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.