Load Specifications
Load data in caliber 7.21 Firebird with .284 | 168gr | Berger Classic Hybrid Hunter 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, Ramshot LRT and Vihtavuori N570.
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% | 57,203 psi | 86% | 2930 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 58,668 psi | 88% | 3068 fps | 99.5% |
| ADI AR 2213 | <<locked>> | 82% | 56,985 psi | 85% | 3041 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 57,305 psi | 86% | 3038 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 58,465 psi | 88% | 3186 fps | 99.9% |
| ADI AR 2225 | <<locked>> | 92% | 57,566 psi | 86% | 3058 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 57,566 psi | 86% | 3035 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 59,828 psi | 90% | 2982 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 57,348 psi | 86% | 3018 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 56,420 psi | 85% | 3087 fps | 99.6% |
| Alliant Reloder-50 | <<locked>> | 94% | 57,072 psi | 86% | 3091 fps | 99.4% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 56,797 psi | 85% | 3005 fps | 99.6% |
| Bofors RP15 | <<locked>> | 84% | 57,174 psi | 86% | 3028 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 57,435 psi | 86% | 3051 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 57,566 psi | 86% | 3035 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 58,508 psi | 88% | 3051 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 59,117 psi | 89% | 3031 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 57,986 psi | 87% | 3012 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 57,696 psi | 86% | 3120 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,305 psi | 57% | 1959 fps | 100% |
| Hodgdon US 869 | <<locked>> | 98% | 59,103 psi | 89% | 3071 fps | 96.7% |
| IMR 4955 Enduron | <<locked>> | 82% | 58,769 psi | 88% | 3002 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 59,741 psi | 90% | 3091 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 57,624 psi | 86% | 2966 fps | 97.7% |
| IMR 8133 Enduron | <<locked>> | 94% | 56,550 psi | 85% | 3051 fps | 100% |
| Lovex D100 | <<locked>> | 92% | 59,756 psi | 90% | 3028 fps | 97.2% |
| Lovex S071 | <<locked>> | 88% | 59,669 psi | 89% | 2966 fps | 100% |
| Norma 217 | <<locked>> | 94% | 58,349 psi | 87% | 3071 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 57,479 psi | 86% | 3054 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 57,725 psi | 87% | 3107 fps | 96.6% |
| Ramshot Magnum | <<locked>> | 86% | 60,321 psi | 90% | 3038 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,305 psi | 59% | 2001 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 58,537 psi | 88% | 3104 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 57,493 psi | 86% | 3084 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 59,756 psi | 90% | 3028 fps | 97.2% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 60,017 psi | 90% | 3071 fps | 99.5% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 53,345 psi | 80% | 2982 fps | 97.4% |
| Vihtavuori 24N41 | <<locked>> | 96% | 59,567 psi | 89% | 3077 fps | 96.7% |
| Vihtavuori N165 | <<locked>> | 84% | 57,914 psi | 87% | 2959 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 57,682 psi | 86% | 3009 fps | 98.8% |
| Vihtavuori N565 | <<locked>> | 86% | 59,016 psi | 88% | 3061 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 57,493 psi | 86% | 3084 fps | 100% |
| Vihtavuori N570 | <<locked>> | 90% | 59,495 psi | 89% | 3159 fps | 99.6% |
| Winchester StaBALL HD | <<locked>> | 82% | 58,334 psi | 87% | 3035 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 82% | 57,276 psi | 86% | 2963 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% | 53,592 psi | 80% | 2877 fps | 100% |
| Accurate 8700 | <<locked>> | 90% | 40,625 psi | 61% | 2740 fps | 95.8% |
| ADI AR 2213 | <<locked>> | 80% | 53,243 psi | 80% | 2982 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 40,248 psi | 60% | 2736 fps | 99.2% |
| ADI AR 2218 | 89.1 gr | 82% | 37,304 psi | 56% | 2743 fps | 95% |
| ADI AR 2225 | <<locked>> | 80% | 37,608 psi | 56% | 2710 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 53,954 psi | 81% | 2979 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 52,562 psi | 79% | 2881 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 46,731 psi | 70% | 2851 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 80% | 38,798 psi | 58% | 2740 fps | 95.6% |
| Alliant Reloder-50 | <<locked>> | 84% | 39,494 psi | 59% | 2746 fps | 95.2% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 49,835 psi | 75% | 2884 fps | 98.8% |
| Bofors RP15 | <<locked>> | 80% | 50,241 psi | 75% | 2917 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 43,772 psi | 66% | 2812 fps | 99.6% |
| Bofors RP5 | <<locked>> | 80% | 53,954 psi | 81% | 2979 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 43,976 psi | 66% | 2808 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 80% | 55,245 psi | 83% | 2969 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 80% | 54,331 psi | 81% | 2953 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 46,369 psi | 70% | 2936 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,790 psi | 43% | 1752 fps | 100% |
| Hodgdon US 869 | <<locked>> | 96% | 55,042 psi | 83% | 3002 fps | 95.8% |
| IMR 4955 Enduron | <<locked>> | 80% | 55,042 psi | 83% | 2943 fps | 100% |
| IMR 7828 SSC | <<locked>> | 80% | 52,040 psi | 78% | 2969 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 82% | 47,413 psi | 71% | 2785 fps | 95.3% |
| IMR 8133 Enduron | <<locked>> | 80% | 35,099 psi | 53% | 2631 fps | 97.7% |
| Lovex D100 | <<locked>> | 88% | 51,851 psi | 78% | 2897 fps | 95.5% |
| Lovex S071 | <<locked>> | 80% | 46,369 psi | 70% | 2759 fps | 100% |
| Norma 217 | <<locked>> | 80% | 35,969 psi | 54% | 2661 fps | 99.5% |
| Ramshot Grand | <<locked>> | 80% | 53,417 psi | 80% | 2992 fps | 100% |
| Ramshot LRT | 99.7 gr | 92% | 53,664 psi | 80% | 3038 fps | 95.6% |
| Ramshot Magnum | <<locked>> | 80% | 48,298 psi | 72% | 2858 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,602 psi | 44% | 1795 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 46,456 psi | 70% | 2910 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 42,554 psi | 64% | 2812 fps | 98.7% |
| Shooters World 50 BMG | <<locked>> | 88% | 51,851 psi | 78% | 2897 fps | 95.5% |
| SNPE Vectan SP 13 | <<locked>> | 88% | 39,784 psi | 60% | 2697 fps | 95.1% |
| Vihtavuori 20N29 | <<locked>> | 96% | 46,296 psi | 69% | 2851 fps | 95.5% |
| Vihtavuori 24N41 | <<locked>> | 94% | 55,579 psi | 83% | 3012 fps | 95.8% |
| Vihtavuori N165 | <<locked>> | 80% | 50,792 psi | 76% | 2848 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 43,903 psi | 66% | 2756 fps | 95.9% |
| Vihtavuori N565 | <<locked>> | 80% | 48,196 psi | 72% | 2881 fps | 99.8% |
| Vihtavuori N568 | <<locked>> | 80% | 43,337 psi | 65% | 2825 fps | 98.4% |
| Vihtavuori N570 | 85.1 gr | 80% | 41,452 psi | 62% | 2815 fps | 96.1% |
| Winchester StaBALL HD | <<locked>> | 80% | 54,143 psi | 81% | 2976 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 53,650 psi | 80% | 2907 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 | 168gr | Berger Classic Hybrid Hunter. ADI AR 2218 delivers the highest muzzle velocity at 3,186 fps; across all powders the maximum-charge window runs from 1,959 fps to 3,186 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 168.0 gr projectile in 0.284" calls for a 1:10.5 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, Ramshot LRT, Vihtavuori N570 rank at the top here: for 7.21 Firebird with the .284 | 168gr | Berger Classic Hybrid Hunter 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.