Load Specifications
Load data in caliber 7.21 Firebird with .284 | 152gr | CutEdge Maximus 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, Vihtavuori N570 and Hodgdon Retumbo.
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.
A valid access license is required to use the Personalized Load Calculator.
You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 86% | 59,248 psi | 89% | 3091 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 51,721 psi | 78% | 3071 fps | 97.8% |
| Accurate MAGPRO | <<locked>> | 84% | 58,755 psi | 88% | 3219 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 82% | 56,507 psi | 85% | 3130 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 59,422 psi | 89% | 3212 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 59,234 psi | 89% | 3196 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 60,307 psi | 90% | 3340 fps | 99.7% |
| ADI AR 2225 | <<locked>> | 96% | 58,755 psi | 88% | 3212 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 59,959 psi | 90% | 3179 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 59,770 psi | 90% | 3202 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 57,957 psi | 87% | 3094 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 58,958 psi | 88% | 3176 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 59,117 psi | 89% | 3189 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 57,943 psi | 87% | 3238 fps | 99.2% |
| Alliant Reloder-50 | <<locked>> | 98% | 57,870 psi | 87% | 3225 fps | 98.9% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 59,640 psi | 89% | 3173 fps | 99.4% |
| Bofors RP15 | <<locked>> | 88% | 59,088 psi | 89% | 3192 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 58,885 psi | 88% | 3205 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 59,770 psi | 90% | 3202 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 56,347 psi | 84% | 3150 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 57,754 psi | 87% | 3136 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 84% | 56,797 psi | 85% | 3123 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 60,321 psi | 90% | 3074 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 58,914 psi | 88% | 3281 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,971 psi | 57% | 2041 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 57,812 psi | 87% | 3114 fps | 100% |
| IMR 7828 SSC | <<locked>> | 86% | 58,073 psi | 87% | 3199 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 92% | 60,292 psi | 90% | 3123 fps | 97.1% |
| IMR 8133 Enduron | <<locked>> | 98% | 57,508 psi | 86% | 3196 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 57,493 psi | 86% | 3068 fps | 100% |
| Norma 217 | <<locked>> | 98% | 59,030 psi | 88% | 3215 fps | 100% |
| Norma MRP | <<locked>> | 84% | 60,292 psi | 90% | 3219 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 59,698 psi | 89% | 3222 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 58,204 psi | 87% | 3140 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,899 psi | 58% | 2087 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 60,220 psi | 90% | 3264 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 59,088 psi | 89% | 3238 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 56,753 psi | 85% | 3097 fps | 100% |
| Rottweil R 905 | <<locked>> | 84% | 59,741 psi | 90% | 3169 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 53,432 psi | 80% | 3081 fps | 97.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 59,379 psi | 89% | 3166 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 57,972 psi | 87% | 3084 fps | 99.9% |
| Somchem S385 | <<locked>> | 84% | 59,930 psi | 90% | 3133 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 60,191 psi | 90% | 3120 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 59,727 psi | 90% | 3159 fps | 98.4% |
| Vihtavuori N555 | <<locked>> | 84% | 59,466 psi | 89% | 3123 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 59,509 psi | 89% | 3228 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 56,710 psi | 85% | 3156 fps | 100% |
| Vihtavuori N568 | <<locked>> | 92% | 59,146 psi | 89% | 3238 fps | 99.9% |
| Vihtavuori N570 | <<locked>> | 92% | 56,637 psi | 85% | 3241 fps | 98.7% |
| Winchester StaBALL HD | <<locked>> | 86% | 59,480 psi | 89% | 3192 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 60,104 psi | 90% | 3133 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% | 48,182 psi | 72% | 2917 fps | 100% |
| Accurate 8700 | <<locked>> | 96% | 44,237 psi | 66% | 2927 fps | 95.9% |
| Accurate MAGPRO | <<locked>> | 80% | 50,879 psi | 76% | 3081 fps | 99.2% |
| ADI AR 2209 | <<locked>> | 80% | 52,808 psi | 79% | 3071 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 48,066 psi | 72% | 3018 fps | 99.5% |
| ADI AR 2217 | <<locked>> | 80% | 35,650 psi | 53% | 2740 fps | 97% |
| ADI AR 2218 | 95 gr | 88% | 41,046 psi | 62% | 2946 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 80% | 32,895 psi | 49% | 2707 fps | 98.8% |
| Alliant Reloder-19 | <<locked>> | 80% | 52,446 psi | 79% | 3058 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 48,689 psi | 73% | 3018 fps | 99.9% |
| Alliant Reloder-23 | <<locked>> | 80% | 47,282 psi | 71% | 2930 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 41,597 psi | 62% | 2884 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 54,781 psi | 82% | 3123 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 86% | 42,569 psi | 64% | 2940 fps | 95.7% |
| Alliant Reloder-50 | <<locked>> | 90% | 42,627 psi | 64% | 2930 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 45,614 psi | 68% | 2920 fps | 97% |
| Bofors RP15 | <<locked>> | 80% | 45,223 psi | 68% | 2946 fps | 99.6% |
| Bofors RP30 | <<locked>> | 80% | 38,638 psi | 58% | 2822 fps | 98% |
| Bofors RP5 | <<locked>> | 80% | 48,689 psi | 73% | 3018 fps | 99.9% |
| Hodgdon H1000 | <<locked>> | 80% | 38,986 psi | 58% | 2825 fps | 98.6% |
| Hodgdon H4831 | <<locked>> | 80% | 50,328 psi | 75% | 3012 fps | 99.4% |
| Hodgdon H4831 SC | <<locked>> | 80% | 49,458 psi | 74% | 2995 fps | 99.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 56,594 psi | 85% | 3025 fps | 100% |
| Hodgdon Retumbo | 81.5 gr | 80% | 40,611 psi | 61% | 2946 fps | 99.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,413 psi | 43% | 1827 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 50,821 psi | 76% | 2992 fps | 99.5% |
| IMR 7828 SSC | <<locked>> | 80% | 46,891 psi | 70% | 3002 fps | 99.3% |
| IMR 7977 Enduron | <<locked>> | 88% | 52,866 psi | 79% | 2999 fps | 95.5% |
| IMR 8133 Enduron | <<locked>> | 82% | 32,677 psi | 49% | 2680 fps | 95.5% |
| Lovex S071 | <<locked>> | 80% | 41,394 psi | 62% | 2789 fps | 100% |
| Norma 217 | <<locked>> | 80% | 30,835 psi | 46% | 2641 fps | 97% |
| Norma MRP | <<locked>> | 80% | 52,112 psi | 78% | 3091 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 47,543 psi | 71% | 3018 fps | 99.6% |
| Ramshot Magnum | <<locked>> | 80% | 42,786 psi | 64% | 2877 fps | 99.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,283 psi | 44% | 1873 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 40,422 psi | 61% | 2920 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 37,014 psi | 55% | 2799 fps | 95.9% |
| Rottweil R 904 | <<locked>> | 80% | 53,127 psi | 80% | 3041 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 80% | 52,214 psi | 78% | 3048 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 94% | 43,192 psi | 65% | 2884 fps | 95% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 51,866 psi | 78% | 3045 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 54,273 psi | 81% | 3025 fps | 99.8% |
| Somchem S385 | <<locked>> | 80% | 52,431 psi | 79% | 3015 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 46,021 psi | 69% | 2887 fps | 99.9% |
| Vihtavuori N170 | <<locked>> | 84% | 45,353 psi | 68% | 2900 fps | 95.1% |
| Vihtavuori N555 | <<locked>> | 80% | 52,040 psi | 78% | 3015 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 51,547 psi | 77% | 3094 fps | 99.6% |
| Vihtavuori N565 | <<locked>> | 80% | 42,917 psi | 64% | 2897 fps | 98.4% |
| Vihtavuori N568 | <<locked>> | 80% | 38,087 psi | 57% | 2822 fps | 95.7% |
| Vihtavuori N570 | 88.9 gr | 84% | 42,177 psi | 63% | 2949 fps | 95.1% |
| Winchester StaBALL HD | <<locked>> | 80% | 47,253 psi | 71% | 3009 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 48,544 psi | 73% | 2946 fps | 99.9% |
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 59 powders for 7.21 Firebird loaded with the .284 | 152gr | CutEdge Maximus. ADI AR 2218 delivers the highest muzzle velocity at 3,340 fps; across all powders the maximum-charge window runs from 2,041 fps to 3,340 fps. Accurate 8700 gives the best case fill at 100 %, and 59 of the 59 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 152.0 gr projectile in 0.284" calls for a 1:9.5 twist; slower twists will usually not stabilise this weight. Accurate 8700, Hodgdon TrailBoss, 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, Vihtavuori N570, Hodgdon Retumbo rank at the top here: for 7.21 Firebird with the .284 | 152gr | CutEdge Maximus they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon 50BMG, Vihtavuori 20N29 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.