Load Specifications
Load data in caliber 7.21 Firebird with .284 | 145gr | CutEdge MTH bullet and 52 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>> | 86% | 57,972 psi | 87% | 3133 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 50,096 psi | 75% | 3091 fps | 97.1% |
| Accurate MAGPRO | <<locked>> | 84% | 57,305 psi | 86% | 3251 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 84% | 59,030 psi | 88% | 3232 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 58,030 psi | 87% | 3251 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 57,580 psi | 86% | 3228 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 58,697 psi | 88% | 3373 fps | 99.4% |
| ADI AR 2225 | <<locked>> | 96% | 57,159 psi | 86% | 3248 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 58,581 psi | 88% | 3219 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 58,392 psi | 88% | 3241 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 60,336 psi | 90% | 3192 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 57,435 psi | 86% | 3219 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 57,566 psi | 86% | 3228 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 56,246 psi | 84% | 3261 fps | 98.7% |
| Alliant Reloder-50 | <<locked>> | 98% | 56,202 psi | 84% | 3251 fps | 98.3% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 58,349 psi | 87% | 3209 fps | 99.1% |
| Bofors RP15 | <<locked>> | 88% | 57,754 psi | 87% | 3232 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 57,334 psi | 86% | 3241 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 58,392 psi | 88% | 3241 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 59,059 psi | 89% | 3251 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 56,565 psi | 85% | 3176 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 86% | 59,466 psi | 89% | 3222 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 59,016 psi | 88% | 3120 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 57,145 psi | 86% | 3317 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,884 psi | 57% | 2087 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 56,579 psi | 85% | 3153 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 86% | 56,478 psi | 85% | 3232 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 92% | 59,234 psi | 89% | 3159 fps | 96.5% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 59,770 psi | 90% | 3291 fps | 100% |
| Lovex S071 | <<locked>> | 92% | 59,915 psi | 90% | 3159 fps | 100% |
| Norma 217 | <<locked>> | 98% | 57,392 psi | 86% | 3251 fps | 100% |
| Norma MRP | <<locked>> | 84% | 58,610 psi | 88% | 3255 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 58,102 psi | 87% | 3258 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 56,594 psi | 85% | 3176 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,783 psi | 58% | 2133 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 58,291 psi | 87% | 3301 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 57,421 psi | 86% | 3268 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 84% | 59,263 psi | 89% | 3199 fps | 100% |
| Rottweil R 905 | <<locked>> | 84% | 58,508 psi | 88% | 3212 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 51,938 psi | 78% | 3107 fps | 97.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 58,146 psi | 87% | 3209 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 56,855 psi | 85% | 3123 fps | 99.8% |
| Somchem S385 | <<locked>> | 84% | 58,508 psi | 88% | 3169 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 58,900 psi | 88% | 3159 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 58,450 psi | 88% | 3196 fps | 97.8% |
| Vihtavuori N555 | <<locked>> | 84% | 58,015 psi | 87% | 3166 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 57,928 psi | 87% | 3261 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 90% | 59,263 psi | 89% | 3255 fps | 100% |
| Vihtavuori N568 | <<locked>> | 92% | 57,653 psi | 86% | 3271 fps | 99.6% |
| Vihtavuori N570 | <<locked>> | 94% | 59,277 psi | 89% | 3343 fps | 98.8% |
| Winchester StaBALL HD | <<locked>> | 86% | 57,696 psi | 86% | 3232 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 58,813 psi | 88% | 3176 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% | 47,021 psi | 70% | 2956 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 46,441 psi | 70% | 3022 fps | 96% |
| Accurate MAGPRO | <<locked>> | 80% | 49,632 psi | 74% | 3114 fps | 98.8% |
| ADI AR 2209 | <<locked>> | 80% | 51,619 psi | 77% | 3107 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 46,833 psi | 70% | 3048 fps | 99% |
| ADI AR 2217 | <<locked>> | 80% | 34,650 psi | 52% | 2762 fps | 96.1% |
| ADI AR 2218 | 98 gr | 90% | 43,004 psi | 64% | 3041 fps | 95.4% |
| ADI AR 2225 | <<locked>> | 80% | 31,995 psi | 48% | 2726 fps | 98% |
| Alliant Reloder-19 | <<locked>> | 80% | 51,271 psi | 77% | 3097 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 47,471 psi | 71% | 3048 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 46,079 psi | 69% | 2969 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 40,379 psi | 61% | 2913 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 53,345 psi | 80% | 3166 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 88% | 44,527 psi | 67% | 3035 fps | 95.9% |
| Alliant Reloder-50 | <<locked>> | 92% | 44,614 psi | 67% | 3022 fps | 95.3% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 44,686 psi | 67% | 2953 fps | 96.3% |
| Bofors RP15 | <<locked>> | 80% | 44,063 psi | 66% | 2976 fps | 99.2% |
| Bofors RP30 | <<locked>> | 80% | 37,492 psi | 56% | 2841 fps | 97.1% |
| Bofors RP5 | <<locked>> | 80% | 47,471 psi | 71% | 3048 fps | 99.7% |
| Hodgdon H1000 | <<locked>> | 80% | 37,855 psi | 57% | 2848 fps | 97.9% |
| Hodgdon H4831 | <<locked>> | 80% | 49,124 psi | 74% | 3045 fps | 99% |
| Hodgdon H4831 SC | <<locked>> | 80% | 48,312 psi | 72% | 3028 fps | 98.9% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 55,201 psi | 83% | 3064 fps | 100% |
| Hodgdon Retumbo | 82.3 gr | 80% | 39,479 psi | 59% | 2976 fps | 99.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,413 psi | 43% | 1873 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 49,763 psi | 75% | 3028 fps | 99.2% |
| IMR 7828 SSC | <<locked>> | 80% | 45,629 psi | 68% | 3031 fps | 98.9% |
| IMR 7977 Enduron | <<locked>> | 90% | 55,317 psi | 83% | 3094 fps | 95.7% |
| IMR 8133 Enduron | <<locked>> | 84% | 33,997 psi | 51% | 2762 fps | 95.6% |
| Lovex S071 | <<locked>> | 80% | 40,393 psi | 61% | 2822 fps | 99.8% |
| Norma 217 | <<locked>> | 80% | 29,747 psi | 45% | 2657 fps | 95.9% |
| Norma MRP | <<locked>> | 80% | 50,865 psi | 76% | 3127 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 46,253 psi | 69% | 3048 fps | 99.2% |
| Ramshot Magnum | <<locked>> | 80% | 41,626 psi | 62% | 2907 fps | 99.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,138 psi | 44% | 1916 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 39,015 psi | 58% | 2943 fps | 99.7% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 38,798 psi | 58% | 2894 fps | 96.1% |
| Rottweil R 904 | <<locked>> | 80% | 52,011 psi | 78% | 3077 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 80% | 51,010 psi | 76% | 3087 fps | 99.9% |
| SNPE Vectan SP 13 | <<locked>> | 96% | 45,005 psi | 67% | 2969 fps | 95.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 50,676 psi | 76% | 3081 fps | 99.9% |
| Somchem S361 | <<locked>> | 80% | 53,229 psi | 80% | 3064 fps | 99.5% |
| Somchem S385 | <<locked>> | 80% | 51,242 psi | 77% | 3054 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 44,904 psi | 67% | 2923 fps | 99.7% |
| Vihtavuori N170 | <<locked>> | 86% | 47,442 psi | 71% | 2992 fps | 95.2% |
| Vihtavuori N555 | <<locked>> | 80% | 50,778 psi | 76% | 3054 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 50,343 psi | 75% | 3130 fps | 99.2% |
| Vihtavuori N565 | <<locked>> | 80% | 41,727 psi | 63% | 2923 fps | 97.7% |
| Vihtavuori N568 | <<locked>> | 82% | 39,842 psi | 60% | 2917 fps | 95.9% |
| Vihtavuori N570 | 91.8 gr | 86% | 44,077 psi | 66% | 3045 fps | 95.2% |
| Winchester StaBALL HD | <<locked>> | 80% | 45,788 psi | 69% | 3041 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 47,543 psi | 71% | 2986 fps | 99.7% |
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 52 powders for 7.21 Firebird loaded with the .284 | 145gr | CutEdge MTH. ADI AR 2218 delivers the highest muzzle velocity at 3,373 fps; across all powders the maximum-charge window runs from 2,087 fps to 3,373 fps. Accurate 8700 gives the best case fill at 100 %, and 52 of the 52 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 145.0 gr projectile in 0.284" calls for a 1:9.5 twist; slower twists will usually not stabilise this weight. Accurate 8700, Hodgdon TrailBoss, IMR 8133 Enduron 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 | 145gr | CutEdge MTH 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.