Load Specifications
Load data in caliber 7.21 Firebird with .284 | 160gr | CutEdge MTH bullet and 54 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2218, Hodgdon Retumbo 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>> | 84% | 56,884 psi | 85% | 2992 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 53,679 psi | 80% | 3048 fps | 98.6% |
| Accurate MAGPRO | <<locked>> | 82% | 56,434 psi | 85% | 3117 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 82% | 58,117 psi | 87% | 3091 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 57,232 psi | 86% | 3114 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 57,000 psi | 85% | 3097 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 57,899 psi | 87% | 3241 fps | 99.7% |
| ADI AR 2225 | <<locked>> | 94% | 56,826 psi | 85% | 3120 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 57,566 psi | 86% | 3077 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 57,653 psi | 86% | 3104 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 59,727 psi | 90% | 3051 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 57,029 psi | 85% | 3081 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 59,973 psi | 90% | 3209 fps | 99.6% |
| Alliant Reloder-50 | <<locked>> | 98% | 60,249 psi | 90% | 3202 fps | 99.4% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 57,305 psi | 86% | 3074 fps | 99.4% |
| Bofors RP15 | <<locked>> | 86% | 57,043 psi | 86% | 3094 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 56,797 psi | 85% | 3107 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 57,653 psi | 86% | 3104 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 58,421 psi | 88% | 3117 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 59,451 psi | 89% | 3097 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 58,465 psi | 88% | 3084 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 56,884 psi | 85% | 3179 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,927 psi | 57% | 1991 fps | 100% |
| Hodgdon US 869ᴾ | <<locked>> | 100% | 58,566 psi | 88% | 3117 fps | 96% |
| IMR 4955 Enduron | <<locked>> | 84% | 59,263 psi | 89% | 3071 fps | 100% |
| IMR 7828 SSC | <<locked>> | 86% | 59,799 psi | 90% | 3156 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 58,030 psi | 87% | 3028 fps | 97.2% |
| IMR 8133 Enduron | <<locked>> | 98% | 59,553 psi | 89% | 3163 fps | 100% |
| Lovex D100 | <<locked>> | 94% | 59,741 psi | 90% | 3084 fps | 96.7% |
| Lovex S071 | <<locked>> | 90% | 59,234 psi | 89% | 3025 fps | 100% |
| Norma 217 | <<locked>> | 96% | 57,319 psi | 86% | 3127 fps | 100% |
| Norma MRP | <<locked>> | 82% | 57,812 psi | 87% | 3114 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 57,421 psi | 86% | 3120 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 60,118 psi | 90% | 3100 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,030 psi | 59% | 2037 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 57,841 psi | 87% | 3163 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 56,811 psi | 85% | 3140 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 58,233 psi | 87% | 3058 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 57,493 psi | 86% | 3068 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 94% | 59,741 psi | 90% | 3084 fps | 96.7% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 55,201 psi | 83% | 3054 fps | 98.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 57,130 psi | 86% | 3064 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 59,567 psi | 89% | 3048 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 57,551 psi | 86% | 3031 fps | 100% |
| Vihtavuori 24N41 | <<locked>> | 98% | 59,451 psi | 89% | 3133 fps | 96.1% |
| Vihtavuori N165 | <<locked>> | 86% | 57,841 psi | 87% | 3022 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 57,392 psi | 86% | 3064 fps | 98.4% |
| Vihtavuori N555 | <<locked>> | 82% | 57,305 psi | 86% | 3025 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 57,072 psi | 86% | 3123 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 58,668 psi | 88% | 3123 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 57,000 psi | 85% | 3140 fps | 99.9% |
| Vihtavuori N570 | <<locked>> | 92% | 58,755 psi | 88% | 3215 fps | 99.3% |
| Winchester StaBALL HD | <<locked>> | 84% | 57,377 psi | 86% | 3094 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 57,667 psi | 86% | 3035 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% | 49,661 psi | 74% | 2881 fps | 100% |
| Accurate 8700 | <<locked>> | 94% | 42,699 psi | 64% | 2841 fps | 95.9% |
| Accurate MAGPRO | <<locked>> | 80% | 52,576 psi | 79% | 3048 fps | 99.6% |
| ADI AR 2209 | <<locked>> | 80% | 54,302 psi | 81% | 3028 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 49,617 psi | 74% | 2982 fps | 99.8% |
| ADI AR 2217 | <<locked>> | 80% | 36,898 psi | 55% | 2717 fps | 98% |
| ADI AR 2218 | 92.3 gr | 86% | 39,508 psi | 59% | 2858 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 80% | 34,156 psi | 51% | 2684 fps | 99.4% |
| Alliant Reloder-19 | <<locked>> | 80% | 53,911 psi | 81% | 3018 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 50,227 psi | 75% | 2979 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 48,950 psi | 73% | 2894 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 43,134 psi | 65% | 2851 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 84% | 40,930 psi | 61% | 2848 fps | 95.7% |
| Alliant Reloder-50 | <<locked>> | 88% | 41,118 psi | 62% | 2838 fps | 95.2% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 46,920 psi | 70% | 2887 fps | 97.8% |
| Bofors RP15 | <<locked>> | 80% | 46,644 psi | 70% | 2913 fps | 99.9% |
| Bofors RP30 | <<locked>> | 80% | 40,059 psi | 60% | 2795 fps | 98.7% |
| Bofors RP5 | <<locked>> | 80% | 50,227 psi | 75% | 2979 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 40,393 psi | 61% | 2799 fps | 99.2% |
| Hodgdon H4831 | <<locked>> | 80% | 51,779 psi | 78% | 2976 fps | 99.7% |
| Hodgdon H4831 SC | <<locked>> | 80% | 50,894 psi | 76% | 2959 fps | 99.7% |
| Hodgdon Retumbo | 81 gr | 80% | 42,250 psi | 63% | 2923 fps | 99.9% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,587 psi | 43% | 1788 fps | 100% |
| Hodgdon US 869 | <<locked>> | 98% | 54,563 psi | 82% | 3048 fps | 95% |
| IMR 4955 Enduron | <<locked>> | 80% | 52,112 psi | 78% | 2956 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 80% | 48,472 psi | 73% | 2969 fps | 99.7% |
| IMR 7977 Enduron | <<locked>> | 86% | 50,865 psi | 76% | 2907 fps | 95.6% |
| IMR 8133 Enduron | <<locked>> | 80% | 31,720 psi | 48% | 2598 fps | 95.6% |
| Lovex D100 | <<locked>> | 92% | 55,506 psi | 83% | 3015 fps | 95.7% |
| Lovex S071 | <<locked>> | 80% | 42,670 psi | 64% | 2756 fps | 100% |
| Norma 217 | <<locked>> | 80% | 32,198 psi | 48% | 2625 fps | 98.1% |
| Norma MRP | <<locked>> | 80% | 53,853 psi | 81% | 3051 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 49,298 psi | 74% | 2989 fps | 99.9% |
| Ramshot Magnum | <<locked>> | 80% | 44,425 psi | 67% | 2851 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,356 psi | 44% | 1827 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 42,032 psi | 63% | 2894 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 38,464 psi | 58% | 2779 fps | 97% |
| Rottweil R 904 | <<locked>> | 80% | 54,505 psi | 82% | 2999 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 53,722 psi | 81% | 3012 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 55,506 psi | 83% | 3015 fps | 95.7% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 41,669 psi | 62% | 2795 fps | 95.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 53,417 psi | 80% | 3009 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 55,753 psi | 84% | 2989 fps | 99.9% |
| Somchem S385 | <<locked>> | 80% | 53,911 psi | 81% | 2976 fps | 100% |
| Vihtavuori 24N41 | <<locked>> | 96% | 55,288 psi | 83% | 3064 fps | 95.1% |
| Vihtavuori N165 | <<locked>> | 80% | 47,384 psi | 71% | 2854 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 43,540 psi | 65% | 2805 fps | 95.1% |
| Vihtavuori N555 | <<locked>> | 80% | 53,606 psi | 80% | 2969 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 53,185 psi | 80% | 3058 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 80% | 44,396 psi | 67% | 2871 fps | 99% |
| Vihtavuori N568 | <<locked>> | 80% | 39,465 psi | 59% | 2799 fps | 96.8% |
| Vihtavuori N570 | 86.2 gr | 82% | 40,611 psi | 61% | 2858 fps | 95.1% |
| Winchester StaBALL HD | <<locked>> | 80% | 49,240 psi | 74% | 2972 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 49,995 psi | 75% | 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 57 powders for 7.21 Firebird loaded with the .284 | 160gr | CutEdge MTH. ADI AR 2218 delivers the highest muzzle velocity at 3,241 fps; across all powders the maximum-charge window runs from 1,991 fps to 3,241 fps. Accurate 8700 gives the best case fill at 100 %, and 57 of the 57 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 160.0 gr projectile in 0.284" calls for a 1:9.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, Hodgdon TrailBoss, Hodgdon US 869 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, Hodgdon Retumbo, Vihtavuori N570 rank at the top here: for 7.21 Firebird with the .284 | 160gr | CutEdge MTH 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.