Load Specifications
Load data in caliber 7.21 Firebird with .284 | 170gr | Norma VULKAN 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 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% | 58,624 psi | 88% | 2933 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 56,376 psi | 85% | 3015 fps | 99.4% |
| ADI AR 2213 | <<locked>> | 82% | 58,450 psi | 88% | 3051 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 58,972 psi | 88% | 3045 fps | 100% |
| ADI AR 2218 | <<locked>> | 92% | 56,115 psi | 84% | 3130 fps | 99.8% |
| ADI AR 2225 | <<locked>> | 92% | 59,509 psi | 89% | 3064 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 59,001 psi | 88% | 3038 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 82% | 57,595 psi | 86% | 2933 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 59,074 psi | 89% | 3022 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 58,218 psi | 87% | 3100 fps | 99.8% |
| Alliant Reloder-50 | <<locked>> | 94% | 59,030 psi | 88% | 3104 fps | 99.6% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 58,088 psi | 87% | 3012 fps | 99.8% |
| Bofors RP15 | <<locked>> | 84% | 58,784 psi | 88% | 3038 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 58,929 psi | 88% | 3054 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 59,001 psi | 88% | 3038 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 60,220 psi | 90% | 3054 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 59,335 psi | 89% | 3018 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 59,654 psi | 89% | 3130 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,261 psi | 57% | 1952 fps | 100% |
| Hodgdon US 869 | <<locked>> | 96% | 56,666 psi | 85% | 3015 fps | 96.4% |
| IMR 4955 Enduron | <<locked>> | 82% | 60,031 psi | 90% | 3005 fps | 100% |
| IMR 7828 SSC | <<locked>> | 82% | 57,392 psi | 86% | 3038 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 58,958 psi | 88% | 2976 fps | 98.1% |
| IMR 8133 Enduron | <<locked>> | 94% | 58,204 psi | 87% | 3061 fps | 100% |
| Lovex D100 | <<locked>> | 90% | 57,145 psi | 86% | 2976 fps | 96.9% |
| Lovex S071 | <<locked>> | 86% | 57,319 psi | 86% | 2917 fps | 100% |
| Norma 217 | <<locked>> | 94% | 60,278 psi | 90% | 3081 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 59,292 psi | 89% | 3061 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 59,582 psi | 89% | 3120 fps | 97.2% |
| Ramshot Magnum | <<locked>> | 84% | 57,566 psi | 86% | 2982 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,407 psi | 59% | 1998 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 84% | 56,043 psi | 84% | 3048 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 59,321 psi | 89% | 3094 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 57,145 psi | 86% | 2976 fps | 96.9% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 57,769 psi | 87% | 3022 fps | 99.3% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 55,259 psi | 83% | 2999 fps | 97.9% |
| Vihtavuori 24N41 | <<locked>> | 94% | 57,261 psi | 86% | 3028 fps | 96.4% |
| Vihtavuori N165 | <<locked>> | 84% | 59,263 psi | 89% | 2959 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 59,030 psi | 88% | 3015 fps | 99.1% |
| Vihtavuori N565 | <<locked>> | 84% | 56,768 psi | 85% | 3012 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 59,335 psi | 89% | 3094 fps | 100% |
| Vihtavuori N570 | <<locked>> | 88% | 57,130 psi | 86% | 3104 fps | 99.5% |
| Winchester StaBALL HD | <<locked>> | 82% | 60,060 psi | 90% | 3035 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 82% | 58,798 psi | 88% | 2969 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% | 54,824 psi | 82% | 2881 fps | 100% |
| Accurate 8700 | <<locked>> | 88% | 39,059 psi | 59% | 2687 fps | 95.4% |
| ADI AR 2213 | <<locked>> | 80% | 54,708 psi | 82% | 2992 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 41,423 psi | 62% | 2743 fps | 99.5% |
| ADI AR 2218 | 90.6 gr | 82% | 38,522 psi | 58% | 2762 fps | 95.8% |
| ADI AR 2225 | <<locked>> | 80% | 38,914 psi | 58% | 2720 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 55,390 psi | 83% | 2986 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 53,824 psi | 81% | 2881 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 48,196 psi | 72% | 2858 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 80% | 40,190 psi | 60% | 2756 fps | 96.3% |
| Alliant Reloder-50 | 94.2 gr | 84% | 40,901 psi | 61% | 2759 fps | 95.9% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 51,111 psi | 77% | 2894 fps | 99.1% |
| Bofors RP15 | <<locked>> | 80% | 51,445 psi | 77% | 2920 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 44,976 psi | 67% | 2822 fps | 99.8% |
| Bofors RP5 | <<locked>> | 80% | 55,390 psi | 83% | 2986 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 45,339 psi | 68% | 2822 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 80% | 55,666 psi | 83% | 2963 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 48,008 psi | 72% | 2946 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,892 psi | 43% | 1749 fps | 100% |
| Hodgdon US 869 | <<locked>> | 94% | 52,837 psi | 79% | 2949 fps | 95.4% |
| IMR 4955 Enduron | <<locked>> | 80% | 56,289 psi | 84% | 2949 fps | 100% |
| IMR 7828 SSC | <<locked>> | 80% | 53,534 psi | 80% | 2976 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 80% | 45,368 psi | 68% | 2733 fps | 95% |
| IMR 8133 Enduron | <<locked>> | 80% | 36,230 psi | 54% | 2641 fps | 98.2% |
| Lovex D100 | <<locked>> | 86% | 49,690 psi | 74% | 2844 fps | 95.1% |
| Lovex S071 | <<locked>> | 80% | 47,413 psi | 71% | 2762 fps | 100% |
| Norma 217 | <<locked>> | 80% | 37,188 psi | 56% | 2674 fps | 99.7% |
| Ramshot Grand | <<locked>> | 80% | 54,984 psi | 82% | 2999 fps | 100% |
| Ramshot LRT | <<locked>> | 90% | 51,648 psi | 77% | 2982 fps | 95.2% |
| Ramshot Magnum | <<locked>> | 80% | 49,661 psi | 74% | 2861 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,718 psi | 45% | 1791 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 48,167 psi | 72% | 2923 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 44,019 psi | 66% | 2828 fps | 99.1% |
| Shooters World 50 BMG | <<locked>> | 86% | 49,690 psi | 74% | 2844 fps | 95.1% |
| SNPE Vectan SP 13 | <<locked>> | 88% | 41,046 psi | 62% | 2713 fps | 95.7% |
| Vihtavuori 20N29 | <<locked>> | 94% | 44,599 psi | 67% | 2802 fps | 95.2% |
| Vihtavuori 24N41 | <<locked>> | 92% | 53,330 psi | 80% | 2959 fps | 95.5% |
| Vihtavuori N165 | <<locked>> | 80% | 51,909 psi | 78% | 2854 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 45,165 psi | 68% | 2769 fps | 96.5% |
| Vihtavuori N565 | <<locked>> | 80% | 49,530 psi | 74% | 2890 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 80% | 44,686 psi | 67% | 2838 fps | 98.8% |
| Vihtavuori N570 | 86.6 gr | 80% | 42,917 psi | 64% | 2835 fps | 96.7% |
| Winchester StaBALL HD | <<locked>> | 80% | 55,927 psi | 84% | 2979 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 54,795 psi | 82% | 2910 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 | 170gr | Norma VULKAN. ADI AR 2218 delivers the highest muzzle velocity at 3,130 fps; across all powders the maximum-charge window runs from 1,952 fps to 3,130 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 170.0 gr projectile in 0.284" calls for a 1:12.0 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, Alliant Reloder-50 rank at the top here: for 7.21 Firebird with the .284 | 170gr | Norma VULKAN 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.