Load Specifications
Load data in caliber 7.21 Firebird with .284 | 175gr | Nosler AccuBond Long Range 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% | 57,653 psi | 86% | 2884 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 59,045 psi | 89% | 3025 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 82% | 57,464 psi | 86% | 2999 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 57,682 psi | 86% | 2989 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 58,914 psi | 88% | 3146 fps | 100% |
| ADI AR 2225 | <<locked>> | 92% | 58,131 psi | 87% | 3015 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 58,059 psi | 87% | 2989 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 60,321 psi | 90% | 2936 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 57,769 psi | 87% | 2969 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 56,768 psi | 85% | 3048 fps | 99.7% |
| Alliant Reloder-50 | <<locked>> | 94% | 57,595 psi | 86% | 3051 fps | 99.6% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 57,217 psi | 86% | 2963 fps | 99.8% |
| Bofors RP15 | <<locked>> | 84% | 57,667 psi | 86% | 2986 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 57,783 psi | 87% | 3005 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 58,059 psi | 87% | 2989 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 59,088 psi | 89% | 3005 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 59,437 psi | 89% | 2982 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 58,465 psi | 88% | 2966 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 58,247 psi | 87% | 3077 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,348 psi | 57% | 1916 fps | 100% |
| Hodgdon US 869 | <<locked>> | 98% | 59,466 psi | 89% | 3028 fps | 97.1% |
| IMR 4955 Enduron | <<locked>> | 82% | 59,146 psi | 89% | 2956 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 60,365 psi | 90% | 3045 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 58,030 psi | 87% | 2927 fps | 98% |
| IMR 8133 Enduron | <<locked>> | 94% | 57,058 psi | 86% | 3009 fps | 100% |
| Lovex D100 | <<locked>> | 92% | 60,104 psi | 90% | 2986 fps | 97.6% |
| Lovex S071 | <<locked>> | 88% | 59,944 psi | 90% | 2913 fps | 100% |
| Norma 217 | <<locked>> | 94% | 58,885 psi | 88% | 3028 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 58,117 psi | 87% | 3012 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 58,117 psi | 87% | 3068 fps | 97% |
| Ramshot Magnum | <<locked>> | 84% | 56,507 psi | 85% | 2933 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,363 psi | 59% | 1959 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 59,117 psi | 89% | 3061 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 57,943 psi | 87% | 3041 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 60,104 psi | 90% | 2986 fps | 97.6% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 56,376 psi | 85% | 2969 fps | 99.3% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 53,679 psi | 80% | 2943 fps | 97.7% |
| Vihtavuori 24N41 | <<locked>> | 96% | 60,017 psi | 90% | 3038 fps | 97.1% |
| Vihtavuori N165 | <<locked>> | 84% | 58,233 psi | 87% | 2910 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 57,914 psi | 87% | 2966 fps | 99.1% |
| Vihtavuori N565 | <<locked>> | 86% | 59,364 psi | 89% | 3015 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 58,015 psi | 87% | 3041 fps | 100% |
| Vihtavuori N570 | <<locked>> | 90% | 59,915 psi | 90% | 3117 fps | 99.8% |
| Winchester StaBALL HD | <<locked>> | 82% | 58,769 psi | 88% | 2986 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 82% | 57,798 psi | 87% | 2920 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% | 53,940 psi | 81% | 2831 fps | 100% |
| Accurate 8700 | <<locked>> | 88% | 38,043 psi | 57% | 2641 fps | 95.3% |
| ADI AR 2213 | <<locked>> | 80% | 53,679 psi | 80% | 2940 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 40,698 psi | 61% | 2700 fps | 99.5% |
| ADI AR 2218 | 87.3 gr | 82% | 37,666 psi | 56% | 2717 fps | 95.7% |
| ADI AR 2225 | <<locked>> | 80% | 38,116 psi | 57% | 2677 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 54,375 psi | 82% | 2933 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 53,040 psi | 80% | 2835 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 47,282 psi | 71% | 2812 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 80% | 39,204 psi | 59% | 2707 fps | 96.2% |
| Alliant Reloder-50 | 90.8 gr | 84% | 39,885 psi | 60% | 2713 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 50,270 psi | 75% | 2844 fps | 99.1% |
| Bofors RP15 | <<locked>> | 80% | 50,705 psi | 76% | 2874 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 44,135 psi | 66% | 2772 fps | 99.8% |
| Bofors RP5 | <<locked>> | 80% | 54,375 psi | 82% | 2933 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 44,353 psi | 66% | 2769 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 55,637 psi | 83% | 2927 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 80% | 54,694 psi | 82% | 2910 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 46,992 psi | 70% | 2897 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,776 psi | 43% | 1713 fps | 100% |
| Hodgdon US 869 | <<locked>> | 94% | 51,576 psi | 77% | 2897 fps | 95.2% |
| IMR 4955 Enduron | <<locked>> | 80% | 55,506 psi | 83% | 2897 fps | 100% |
| IMR 7828 SSC | <<locked>> | 80% | 52,620 psi | 79% | 2927 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 80% | 44,831 psi | 67% | 2690 fps | 95% |
| IMR 8133 Enduron | <<locked>> | 80% | 35,505 psi | 53% | 2598 fps | 98.2% |
| Lovex D100 | <<locked>> | 86% | 48,704 psi | 73% | 2795 fps | 95% |
| Lovex S071 | <<locked>> | 80% | 46,702 psi | 70% | 2717 fps | 100% |
| Norma 217 | <<locked>> | 80% | 36,303 psi | 54% | 2628 fps | 99.7% |
| Ramshot Grand | <<locked>> | 80% | 53,940 psi | 81% | 2949 fps | 100% |
| Ramshot LRT | <<locked>> | 90% | 50,444 psi | 76% | 2933 fps | 95.1% |
| Ramshot Magnum | <<locked>> | 80% | 48,820 psi | 73% | 2818 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,747 psi | 45% | 1755 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 46,920 psi | 70% | 2871 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 42,989 psi | 64% | 2779 fps | 99% |
| Shooters World 50 BMG | <<locked>> | 86% | 48,704 psi | 73% | 2795 fps | 95% |
| SNPE Vectan SP 13 | <<locked>> | 88% | 40,118 psi | 60% | 2664 fps | 95.6% |
| Vihtavuori 20N29 | <<locked>> | 94% | 43,424 psi | 65% | 2753 fps | 95% |
| Vihtavuori 24N41 | <<locked>> | 92% | 52,069 psi | 78% | 2907 fps | 95.3% |
| Vihtavuori N165 | <<locked>> | 80% | 51,097 psi | 77% | 2805 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 44,280 psi | 66% | 2720 fps | 96.4% |
| Vihtavuori N565 | <<locked>> | 80% | 48,617 psi | 73% | 2841 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 80% | 43,685 psi | 65% | 2789 fps | 98.8% |
| Vihtavuori N570 | 83.4 gr | 80% | 41,901 psi | 63% | 2785 fps | 96.7% |
| Winchester StaBALL HD | <<locked>> | 80% | 54,563 psi | 82% | 2927 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 53,867 psi | 81% | 2864 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 45 powders for 7.21 Firebird loaded with the .284 | 175gr | Nosler AccuBond Long Range. ADI AR 2218 delivers the highest muzzle velocity at 3,146 fps; across all powders the maximum-charge window runs from 1,916 fps to 3,146 fps. Accurate 8700 gives the best case fill at 100 %, and 45 of the 45 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 1:9.0 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 | 175gr | Nosler AccuBond Long Range 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.