Load Specifications
Load data in caliber 7.21 Firebird with .284 | 168gr | Nosler Custom Competition 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-33.
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% | 57,885 psi | 87% | 2940 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 59,611 psi | 89% | 3081 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 82% | 57,667 psi | 86% | 3054 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 57,986 psi | 87% | 3045 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 59,292 psi | 89% | 3199 fps | 100% |
| ADI AR 2225 | <<locked>> | 92% | 58,436 psi | 88% | 3071 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 58,291 psi | 87% | 3045 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 82% | 56,637 psi | 85% | 2940 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 58,059 psi | 87% | 3025 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 57,217 psi | 86% | 3100 fps | 99.6% |
| Alliant Reloder-50 | <<locked>> | 94% | 57,812 psi | 87% | 3100 fps | 99.5% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 57,305 psi | 86% | 3012 fps | 99.7% |
| Bofors RP15 | <<locked>> | 84% | 57,870 psi | 87% | 3038 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 57,957 psi | 87% | 3058 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 58,291 psi | 87% | 3045 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 59,219 psi | 89% | 3058 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 59,596 psi | 89% | 3035 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 58,639 psi | 88% | 3022 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 58,508 psi | 88% | 3130 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,261 psi | 57% | 1959 fps | 100% |
| Hodgdon US 869 | <<locked>> | 98% | 59,770 psi | 90% | 3081 fps | 96.9% |
| IMR 4955 Enduron | <<locked>> | 82% | 59,234 psi | 89% | 3009 fps | 100% |
| IMR 7828 SSC | <<locked>> | 82% | 56,434 psi | 85% | 3041 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 58,175 psi | 87% | 2976 fps | 97.8% |
| IMR 8133 Enduron | <<locked>> | 94% | 57,217 psi | 86% | 3061 fps | 100% |
| Lovex D100 | <<locked>> | 90% | 56,333 psi | 84% | 2976 fps | 96.6% |
| Lovex S071 | <<locked>> | 88% | 60,162 psi | 90% | 2969 fps | 100% |
| Norma 217 | <<locked>> | 94% | 59,219 psi | 89% | 3081 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 58,218 psi | 87% | 3064 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 58,436 psi | 88% | 3120 fps | 96.8% |
| Ramshot Magnum | <<locked>> | 84% | 56,608 psi | 85% | 2986 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,407 psi | 59% | 2005 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 59,277 psi | 89% | 3110 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 58,131 psi | 87% | 3094 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 56,333 psi | 84% | 2976 fps | 96.6% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 56,681 psi | 85% | 3015 fps | 99.1% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 54,186 psi | 81% | 2995 fps | 97.6% |
| Vihtavuori 24N41 | <<locked>> | 94% | 56,246 psi | 84% | 3022 fps | 96% |
| Vihtavuori N165 | <<locked>> | 84% | 58,363 psi | 87% | 2963 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 58,189 psi | 87% | 3018 fps | 98.9% |
| Vihtavuori N565 | <<locked>> | 86% | 59,669 psi | 89% | 3071 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 58,349 psi | 87% | 3094 fps | 100% |
| Vihtavuori N570 | <<locked>> | 90% | 60,147 psi | 90% | 3173 fps | 99.7% |
| Winchester StaBALL HD | <<locked>> | 82% | 58,885 psi | 88% | 3038 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 82% | 57,943 psi | 87% | 2972 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% | 54,085 psi | 81% | 2884 fps | 100% |
| Accurate 8700 | <<locked>> | 90% | 41,162 psi | 62% | 2749 fps | 96.1% |
| ADI AR 2213 | <<locked>> | 80% | 53,795 psi | 81% | 2992 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 40,727 psi | 61% | 2743 fps | 99.3% |
| ADI AR 2218 | 90 gr | 82% | 37,826 psi | 57% | 2756 fps | 95.3% |
| ADI AR 2225 | <<locked>> | 80% | 38,232 psi | 57% | 2720 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 54,476 psi | 82% | 2986 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 53,113 psi | 80% | 2887 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 47,427 psi | 71% | 2861 fps | 100% |
| Alliant Reloder-33 | 89.4 gr | 80% | 39,378 psi | 59% | 2753 fps | 95.8% |
| Alliant Reloder-50 | <<locked>> | 84% | 40,045 psi | 60% | 2756 fps | 95.5% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 50,357 psi | 75% | 2894 fps | 98.9% |
| Bofors RP15 | <<locked>> | 80% | 50,749 psi | 76% | 2923 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 44,251 psi | 66% | 2822 fps | 99.7% |
| Bofors RP5 | <<locked>> | 80% | 54,476 psi | 82% | 2986 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 44,469 psi | 67% | 2818 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 80% | 55,695 psi | 83% | 2976 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 80% | 54,795 psi | 82% | 2963 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 47,137 psi | 71% | 2946 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,834 psi | 43% | 1755 fps | 100% |
| Hodgdon US 869 | <<locked>> | 94% | 51,895 psi | 78% | 2946 fps | 95% |
| IMR 4955 Enduron | <<locked>> | 80% | 55,666 psi | 83% | 2953 fps | 100% |
| IMR 7828 SSC | <<locked>> | 80% | 52,765 psi | 79% | 2979 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 82% | 47,790 psi | 72% | 2795 fps | 95.5% |
| IMR 8133 Enduron | <<locked>> | 80% | 35,578 psi | 53% | 2641 fps | 97.9% |
| Lovex D100 | <<locked>> | 88% | 52,330 psi | 78% | 2907 fps | 95.7% |
| Lovex S071 | <<locked>> | 80% | 46,717 psi | 70% | 2766 fps | 100% |
| Norma 217 | <<locked>> | 80% | 36,477 psi | 55% | 2671 fps | 99.6% |
| Ramshot Grand | <<locked>> | 80% | 54,172 psi | 81% | 3002 fps | 100% |
| Ramshot LRT | <<locked>> | 92% | 54,375 psi | 82% | 3048 fps | 95.8% |
| Ramshot Magnum | <<locked>> | 80% | 48,936 psi | 73% | 2864 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,660 psi | 44% | 1798 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 47,181 psi | 71% | 2920 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 43,178 psi | 65% | 2825 fps | 98.8% |
| Shooters World 50 BMG | <<locked>> | 88% | 52,330 psi | 78% | 2907 fps | 95.7% |
| SNPE Vectan SP 13 | <<locked>> | 88% | 40,277 psi | 60% | 2707 fps | 95.3% |
| Vihtavuori 20N29 | <<locked>> | 96% | 46,949 psi | 70% | 2864 fps | 95.8% |
| Vihtavuori 24N41 | <<locked>> | 92% | 52,315 psi | 78% | 2956 fps | 95% |
| Vihtavuori N165 | <<locked>> | 80% | 51,256 psi | 77% | 2858 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 44,425 psi | 67% | 2769 fps | 96.1% |
| Vihtavuori N565 | <<locked>> | 80% | 48,689 psi | 73% | 2890 fps | 99.8% |
| Vihtavuori N568 | <<locked>> | 80% | 43,816 psi | 66% | 2835 fps | 98.5% |
| Vihtavuori N570 | 86 gr | 80% | 42,061 psi | 63% | 2828 fps | 96.3% |
| Winchester StaBALL HD | <<locked>> | 80% | 54,824 psi | 82% | 2982 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 54,143 psi | 81% | 2917 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 | Nosler Custom Competition. ADI AR 2218 delivers the highest muzzle velocity at 3,199 fps; across all powders the maximum-charge window runs from 1,959 fps to 3,199 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 1:11.5 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-33 rank at the top here: for 7.21 Firebird with the .284 | 168gr | Nosler Custom Competition 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.