Load Specifications
Load data in caliber 7.21 Firebird with .284 | 175gr | Nosler Partition bullet and 44 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.
A valid access license is required to use the Personalized Load Calculator.
You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 82% | 58,827 psi | 88% | 2897 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 56,478 psi | 85% | 2986 fps | 99.5% |
| ADI AR 2213 | <<locked>> | 82% | 58,682 psi | 88% | 3015 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 59,030 psi | 88% | 3009 fps | 100% |
| ADI AR 2218 | <<locked>> | 92% | 56,057 psi | 84% | 3097 fps | 99.9% |
| ADI AR 2225 | <<locked>> | 92% | 59,466 psi | 89% | 3028 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 59,248 psi | 89% | 3005 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 82% | 57,537 psi | 86% | 2897 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 58,987 psi | 88% | 2986 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 58,349 psi | 87% | 3068 fps | 99.8% |
| Alliant Reloder-50 | <<locked>> | 94% | 59,132 psi | 89% | 3071 fps | 99.7% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 58,117 psi | 87% | 2976 fps | 99.8% |
| Bofors RP15 | <<locked>> | 84% | 58,827 psi | 88% | 2999 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 59,103 psi | 89% | 3022 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 59,248 psi | 89% | 3005 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 60,278 psi | 90% | 3022 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 59,582 psi | 89% | 2982 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 59,625 psi | 89% | 3091 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,334 psi | 57% | 1919 fps | 100% |
| Hodgdon US 869 | <<locked>> | 96% | 56,782 psi | 85% | 2986 fps | 96.6% |
| IMR 4955 Enduron | <<locked>> | 82% | 60,046 psi | 90% | 2966 fps | 100% |
| IMR 7828 SSC | <<locked>> | 82% | 57,406 psi | 86% | 2999 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 58,943 psi | 88% | 2940 fps | 98.2% |
| IMR 8133 Enduron | <<locked>> | 94% | 58,349 psi | 87% | 3025 fps | 100% |
| Lovex D100 | <<locked>> | 90% | 57,246 psi | 86% | 2943 fps | 97.1% |
| Lovex S071 | <<locked>> | 86% | 57,479 psi | 86% | 2881 fps | 100% |
| Norma 217 | <<locked>> | 94% | 60,234 psi | 90% | 3041 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 59,408 psi | 89% | 3025 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 59,596 psi | 89% | 3087 fps | 97.4% |
| Ramshot Magnum | <<locked>> | 84% | 57,609 psi | 86% | 2946 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,508 psi | 59% | 1965 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 84% | 56,144 psi | 84% | 3015 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 59,422 psi | 89% | 3061 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 57,246 psi | 86% | 2943 fps | 97.1% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 57,783 psi | 87% | 2989 fps | 99.4% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 55,230 psi | 83% | 2966 fps | 98.1% |
| Vihtavuori 24N41 | <<locked>> | 94% | 57,246 psi | 86% | 2992 fps | 96.6% |
| Vihtavuori N165 | <<locked>> | 84% | 59,292 psi | 89% | 2923 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 59,190 psi | 89% | 2986 fps | 99.2% |
| Vihtavuori N565 | <<locked>> | 84% | 56,739 psi | 85% | 2976 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 59,277 psi | 89% | 3058 fps | 100% |
| Vihtavuori N570 | <<locked>> | 88% | 57,290 psi | 86% | 3074 fps | 99.6% |
| Winchester StaBALL HD | <<locked>> | 82% | 60,220 psi | 90% | 2999 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 82% | 58,871 psi | 88% | 2936 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% | 54,940 psi | 82% | 2844 fps | 100% |
| Accurate 8700 | <<locked>> | 88% | 39,160 psi | 59% | 2664 fps | 95.8% |
| ADI AR 2213 | <<locked>> | 80% | 54,694 psi | 82% | 2953 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 41,510 psi | 62% | 2713 fps | 99.6% |
| ADI AR 2218 | 88.9 gr | 82% | 38,551 psi | 58% | 2736 fps | 96.2% |
| ADI AR 2225 | <<locked>> | 80% | 39,059 psi | 59% | 2694 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 55,376 psi | 83% | 2946 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 53,911 psi | 81% | 2844 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 48,298 psi | 72% | 2825 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 80% | 40,176 psi | 60% | 2723 fps | 96.5% |
| Alliant Reloder-50 | <<locked>> | 82% | 38,072 psi | 57% | 2667 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 50,995 psi | 76% | 2858 fps | 99.2% |
| Bofors RP15 | <<locked>> | 80% | 51,532 psi | 77% | 2884 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 45,107 psi | 68% | 2789 fps | 99.9% |
| Bofors RP5 | <<locked>> | 80% | 55,376 psi | 83% | 2946 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 45,353 psi | 68% | 2785 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 80% | 55,622 psi | 83% | 2923 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 48,153 psi | 72% | 2913 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,805 psi | 43% | 1719 fps | 100% |
| Hodgdon US 869 | <<locked>> | 94% | 52,881 psi | 79% | 2917 fps | 95.7% |
| IMR 4955 Enduron | <<locked>> | 80% | 56,405 psi | 85% | 2913 fps | 100% |
| IMR 7828 SSC | <<locked>> | 80% | 53,679 psi | 80% | 2943 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 80% | 45,455 psi | 68% | 2703 fps | 95.2% |
| IMR 8133 Enduron | <<locked>> | 80% | 36,289 psi | 54% | 2615 fps | 98.4% |
| Lovex D100 | <<locked>> | 86% | 49,661 psi | 74% | 2815 fps | 95.4% |
| Lovex S071 | <<locked>> | 80% | 47,558 psi | 71% | 2730 fps | 100% |
| Norma 217 | <<locked>> | 80% | 37,289 psi | 56% | 2644 fps | 99.8% |
| Ramshot Grand | <<locked>> | 80% | 55,056 psi | 83% | 2966 fps | 100% |
| Ramshot LRT | 97.4 gr | 90% | 51,706 psi | 78% | 2953 fps | 95.5% |
| Ramshot Magnum | <<locked>> | 80% | 49,763 psi | 75% | 2831 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,762 psi | 45% | 1762 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 48,153 psi | 72% | 2887 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 44,034 psi | 66% | 2795 fps | 99.2% |
| Shooters World 50 BMG | <<locked>> | 86% | 49,661 psi | 74% | 2815 fps | 95.4% |
| SNPE Vectan SP 13 | <<locked>> | 86% | 38,334 psi | 57% | 2621 fps | 95% |
| Vihtavuori 20N29 | <<locked>> | 94% | 44,556 psi | 67% | 2772 fps | 95.4% |
| Vihtavuori 24N41 | <<locked>> | 92% | 53,229 psi | 80% | 2927 fps | 95.7% |
| Vihtavuori N165 | <<locked>> | 80% | 52,025 psi | 78% | 2818 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 45,208 psi | 68% | 2740 fps | 96.7% |
| Vihtavuori N565 | <<locked>> | 80% | 49,545 psi | 74% | 2858 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 80% | 44,759 psi | 67% | 2805 fps | 99% |
| Vihtavuori N570 | 85 gr | 80% | 42,989 psi | 64% | 2805 fps | 97% |
| Winchester StaBALL HD | <<locked>> | 80% | 55,956 psi | 84% | 2946 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 54,955 psi | 82% | 2877 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 44 powders for 7.21 Firebird loaded with the .284 | 175gr | Nosler Partition. ADI AR 2218 delivers the highest muzzle velocity at 3,097 fps; across all powders the maximum-charge window runs from 1,919 fps to 3,097 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 44 of the 44 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 1:10.5 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, Vihtavuori N570, Ramshot LRT rank at the top here: for 7.21 Firebird with the .284 | 175gr | Nosler Partition 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.