Load Specifications
Load data in caliber 7.21 Firebird with .284 | 140gr | Frontier BTSP bullet and 53 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, ADI AR 2218 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.
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% | 57,725 psi | 87% | 3169 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 49,472 psi | 74% | 3120 fps | 96.5% |
| Accurate MAGPRO | <<locked>> | 84% | 56,811 psi | 85% | 3287 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 84% | 58,566 psi | 88% | 3268 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 57,334 psi | 86% | 3284 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 94% | 56,826 psi | 85% | 3261 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 57,783 psi | 87% | 3396 fps | 99% |
| ADI AR 2225 | <<locked>> | 96% | 56,405 psi | 85% | 3284 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 58,001 psi | 87% | 3251 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 57,885 psi | 87% | 3278 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 59,785 psi | 90% | 3228 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 56,811 psi | 85% | 3255 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 56,840 psi | 85% | 3264 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 59,886 psi | 90% | 3369 fps | 99% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 60,133 psi | 90% | 3360 fps | 98.7% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 57,740 psi | 87% | 3235 fps | 98.8% |
| Bofors RP15 | <<locked>> | 88% | 57,261 psi | 86% | 3264 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 56,840 psi | 85% | 3278 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 57,885 psi | 87% | 3278 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 58,291 psi | 87% | 3284 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 60,031 psi | 90% | 3274 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 86% | 58,856 psi | 88% | 3255 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 58,653 psi | 88% | 3159 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 56,275 psi | 84% | 3353 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,913 psi | 57% | 2116 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 60,191 psi | 90% | 3232 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 59,901 psi | 90% | 3245 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 88% | 59,944 psi | 90% | 3330 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 92% | 58,537 psi | 88% | 3186 fps | 96% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 59,190 psi | 89% | 3327 fps | 100% |
| Lovex S071 | <<locked>> | 92% | 59,683 psi | 89% | 3199 fps | 100% |
| Norma 217 | <<locked>> | 98% | 56,623 psi | 85% | 3287 fps | 100% |
| Norma MRP | <<locked>> | 84% | 58,073 psi | 87% | 3291 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 57,392 psi | 86% | 3291 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 60,307 psi | 90% | 3274 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,827 psi | 58% | 2165 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 57,508 psi | 86% | 3337 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 56,739 psi | 85% | 3301 fps | 99.7% |
| Rottweil R 904 | <<locked>> | 84% | 58,697 psi | 88% | 3232 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 84% | 57,986 psi | 87% | 3245 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 51,474 psi | 77% | 3136 fps | 96.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 57,609 psi | 86% | 3245 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 56,434 psi | 85% | 3156 fps | 99.6% |
| Somchem S385 | <<locked>> | 84% | 58,305 psi | 87% | 3209 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 58,392 psi | 88% | 3196 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 57,885 psi | 87% | 3222 fps | 97.4% |
| Vihtavuori N555 | <<locked>> | 84% | 57,841 psi | 87% | 3205 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 57,348 psi | 86% | 3294 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 90% | 58,827 psi | 88% | 3291 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 92% | 56,884 psi | 85% | 3301 fps | 99.4% |
| Vihtavuori N570 | <<locked>> | 94% | 58,610 psi | 88% | 3376 fps | 98.5% |
| Winchester StaBALL HD | <<locked>> | 86% | 57,029 psi | 85% | 3271 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 58,276 psi | 87% | 3209 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% | 47,123 psi | 71% | 2995 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 45,919 psi | 69% | 3048 fps | 95.5% |
| Accurate MAGPRO | <<locked>> | 80% | 49,255 psi | 74% | 3146 fps | 98.4% |
| ADI AR 2209 | <<locked>> | 80% | 51,068 psi | 77% | 3140 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 80% | 46,340 psi | 69% | 3081 fps | 98.7% |
| ADI AR 2217 | <<locked>> | 80% | 34,650 psi | 52% | 2795 fps | 95.7% |
| ADI AR 2218 | 99.7 gr | 92% | 46,064 psi | 69% | 3153 fps | 96.1% |
| ADI AR 2225 | <<locked>> | 80% | 31,952 psi | 48% | 2762 fps | 97.7% |
| Alliant Reloder-19 | <<locked>> | 80% | 50,981 psi | 76% | 3133 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 47,108 psi | 71% | 3084 fps | 99.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 45,919 psi | 69% | 3012 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 40,045 psi | 60% | 2953 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 52,881 psi | 79% | 3202 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 88% | 44,208 psi | 66% | 3068 fps | 95.4% |
| Alliant Reloder-50 | <<locked>> | 94% | 47,877 psi | 72% | 3130 fps | 96% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 44,309 psi | 66% | 2979 fps | 95.8% |
| Bofors RP15 | <<locked>> | 80% | 43,932 psi | 66% | 3015 fps | 99% |
| Bofors RP30 | <<locked>> | 80% | 37,507 psi | 56% | 2881 fps | 96.8% |
| Bofors RP5 | <<locked>> | 80% | 47,108 psi | 71% | 3084 fps | 99.5% |
| Hodgdon H1000 | <<locked>> | 80% | 37,753 psi | 57% | 2881 fps | 97.5% |
| Hodgdon H4831 | <<locked>> | 80% | 48,878 psi | 73% | 3077 fps | 98.7% |
| Hodgdon H4831 SC | <<locked>> | 80% | 47,892 psi | 72% | 3058 fps | 98.5% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 54,926 psi | 82% | 3107 fps | 100% |
| Hodgdon Retumbo | 81.8 gr | 80% | 39,146 psi | 59% | 3005 fps | 98.9% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,413 psi | 43% | 1900 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 56,521 psi | 85% | 3173 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 49,400 psi | 74% | 3061 fps | 98.9% |
| IMR 7828 SSC | <<locked>> | 80% | 45,179 psi | 68% | 3061 fps | 98.5% |
| IMR 7977 Enduron | <<locked>> | 90% | 54,882 psi | 82% | 3123 fps | 95.1% |
| IMR 8133 Enduron | <<locked>> | 84% | 34,040 psi | 51% | 2805 fps | 95.2% |
| Lovex S071 | <<locked>> | 80% | 40,451 psi | 61% | 2861 fps | 99.8% |
| Norma 217 | <<locked>> | 80% | 29,762 psi | 45% | 2694 fps | 95.5% |
| Norma MRP | <<locked>> | 80% | 50,444 psi | 76% | 3163 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 45,774 psi | 69% | 3081 fps | 98.9% |
| Ramshot Magnum | <<locked>> | 80% | 41,365 psi | 62% | 2943 fps | 99.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,138 psi | 44% | 1942 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 38,754 psi | 58% | 2976 fps | 99.5% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 38,653 psi | 58% | 2930 fps | 95.7% |
| Rottweil R 904 | <<locked>> | 80% | 51,547 psi | 77% | 3110 fps | 99.5% |
| Rottweil R 905 | <<locked>> | 80% | 50,604 psi | 76% | 3120 fps | 99.8% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 47,921 psi | 72% | 3068 fps | 95.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 50,256 psi | 75% | 3117 fps | 99.8% |
| Somchem S361 | <<locked>> | 80% | 52,866 psi | 79% | 3094 fps | 99.3% |
| Somchem S385 | <<locked>> | 80% | 50,952 psi | 76% | 3091 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 44,802 psi | 67% | 2959 fps | 99.5% |
| Vihtavuori N170 | <<locked>> | 88% | 50,589 psi | 76% | 3091 fps | 95.7% |
| Vihtavuori N555 | <<locked>> | 80% | 50,734 psi | 76% | 3094 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 49,893 psi | 75% | 3163 fps | 99% |
| Vihtavuori N565 | <<locked>> | 80% | 41,742 psi | 63% | 2963 fps | 97.4% |
| Vihtavuori N568 | <<locked>> | 82% | 39,639 psi | 59% | 2949 fps | 95.4% |
| Vihtavuori N570 | 93.4 gr | 88% | 47,036 psi | 71% | 3153 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 80% | 45,339 psi | 68% | 3081 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 47,210 psi | 71% | 3018 fps | 99.5% |
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 53 powders for 7.21 Firebird loaded with the .284 | 140gr | Frontier BTSP. ADI AR 2218 delivers the highest muzzle velocity at 3,396 fps; across all powders the maximum-charge window runs from 2,116 fps to 3,396 fps. Accurate 8700 gives the best case fill at 100 %, and 53 of the 53 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 140.0 gr projectile in 0.284" calls for a 1:9.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, Alliant Reloder-50, Hodgdon TrailBoss 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. Hodgdon Retumbo, ADI AR 2218, Vihtavuori N570 rank at the top here: for 7.21 Firebird with the .284 | 140gr | Frontier BTSP 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.