Load Specifications
Load data in caliber 7.21 Firebird with .284 | 130gr | Speer Boat-Tail bullet and 51 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.
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Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 86% | 57,812 psi | 87% | 3261 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 49,995 psi | 75% | 3199 fps | 96.1% |
| Accurate MAGPRO | <<locked>> | 84% | 57,203 psi | 86% | 3379 fps | 99.3% |
| ADI AR 2209 | <<locked>> | 84% | 58,653 psi | 88% | 3360 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 57,551 psi | 86% | 3376 fps | 99.8% |
| ADI AR 2217 | <<locked>> | 94% | 57,145 psi | 86% | 3350 fps | 99.9% |
| ADI AR 2218 | <<locked>> | 98% | 58,334 psi | 87% | 3484 fps | 98.8% |
| ADI AR 2225 | <<locked>> | 96% | 56,826 psi | 85% | 3376 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 58,233 psi | 87% | 3346 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 58,059 psi | 87% | 3369 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 60,046 psi | 90% | 3323 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 57,159 psi | 86% | 3346 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 57,159 psi | 86% | 3360 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 56,072 psi | 84% | 3379 fps | 98% |
| Alliant Reloder-50 | <<locked>> | 98% | 56,376 psi | 85% | 3369 fps | 97.7% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 57,986 psi | 87% | 3327 fps | 98.5% |
| Bofors RP15 | <<locked>> | 88% | 57,421 psi | 86% | 3356 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 57,029 psi | 85% | 3363 fps | 99.9% |
| Bofors RP5 | <<locked>> | 86% | 58,059 psi | 87% | 3369 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 58,610 psi | 88% | 3376 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 60,162 psi | 90% | 3363 fps | 99.7% |
| Hodgdon H4831 SC | <<locked>> | 86% | 59,030 psi | 88% | 3346 fps | 99.7% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 58,726 psi | 88% | 3255 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 56,594 psi | 85% | 3442 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,855 psi | 57% | 2205 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 59,988 psi | 90% | 3337 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 88% | 60,205 psi | 90% | 3425 fps | 99.9% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 59,727 psi | 90% | 3419 fps | 100% |
| Lovex S071 | <<locked>> | 92% | 59,857 psi | 90% | 3294 fps | 100% |
| Norma 217 | <<locked>> | 98% | 57,261 psi | 86% | 3379 fps | 100% |
| Norma MRP | <<locked>> | 84% | 58,421 psi | 88% | 3386 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 57,595 psi | 86% | 3379 fps | 99.9% |
| Ramshot Magnum | <<locked>> | 88% | 56,333 psi | 84% | 3301 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,856 psi | 58% | 2254 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 57,928 psi | 87% | 3425 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 57,261 psi | 86% | 3386 fps | 99.5% |
| Rottweil R 904 | <<locked>> | 84% | 58,827 psi | 88% | 3327 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 84% | 58,044 psi | 87% | 3337 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 51,953 psi | 78% | 3219 fps | 96.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 57,696 psi | 86% | 3337 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 56,739 psi | 85% | 3248 fps | 99.5% |
| Somchem S385 | <<locked>> | 84% | 58,436 psi | 88% | 3304 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 58,682 psi | 88% | 3287 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 58,291 psi | 87% | 3310 fps | 97.1% |
| Vihtavuori N555 | <<locked>> | 84% | 57,827 psi | 87% | 3301 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 57,653 psi | 86% | 3389 fps | 99.6% |
| Vihtavuori N565 | <<locked>> | 90% | 59,161 psi | 89% | 3383 fps | 99.8% |
| Vihtavuori N568 | <<locked>> | 92% | 57,290 psi | 86% | 3389 fps | 99.2% |
| Vihtavuori N570 | <<locked>> | 94% | 58,914 psi | 88% | 3461 fps | 98.2% |
| Winchester StaBALL HD | <<locked>> | 86% | 57,334 psi | 86% | 3363 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 58,392 psi | 88% | 3297 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% | 3081 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 46,383 psi | 70% | 3127 fps | 95% |
| Accurate MAGPRO | <<locked>> | 80% | 49,429 psi | 74% | 3232 fps | 98.1% |
| ADI AR 2209 | <<locked>> | 80% | 51,256 psi | 77% | 3232 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 80% | 46,586 psi | 70% | 3166 fps | 98.4% |
| ADI AR 2217 | <<locked>> | 82% | 37,217 psi | 56% | 2940 fps | 96.1% |
| ADI AR 2218 | 104.6 gr | 92% | 46,296 psi | 69% | 3232 fps | 95.5% |
| ADI AR 2225 | <<locked>> | 80% | 32,053 psi | 48% | 2828 fps | 97% |
| Alliant Reloder-19 | <<locked>> | 80% | 50,995 psi | 76% | 3219 fps | 99.7% |
| Alliant Reloder-22 | <<locked>> | 80% | 47,369 psi | 71% | 3173 fps | 99.3% |
| Alliant Reloder-23 | <<locked>> | 80% | 46,006 psi | 69% | 3097 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 40,219 psi | 60% | 3031 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 52,997 psi | 79% | 3287 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 48,182 psi | 72% | 3225 fps | 96.1% |
| Alliant Reloder-50 | <<locked>> | 94% | 48,457 psi | 73% | 3212 fps | 95.6% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 44,454 psi | 67% | 3061 fps | 95.3% |
| Bofors RP15 | <<locked>> | 80% | 44,005 psi | 66% | 3097 fps | 98.6% |
| Bofors RP30 | <<locked>> | 80% | 37,521 psi | 56% | 2953 fps | 96.2% |
| Bofors RP5 | <<locked>> | 80% | 47,369 psi | 71% | 3173 fps | 99.3% |
| Hodgdon H1000 | <<locked>> | 80% | 37,826 psi | 57% | 2956 fps | 97% |
| Hodgdon H4831 | <<locked>> | 80% | 48,950 psi | 73% | 3163 fps | 98.4% |
| Hodgdon H4831 SC | <<locked>> | 80% | 48,153 psi | 72% | 3146 fps | 98.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 54,926 psi | 82% | 3199 fps | 100% |
| Hodgdon Retumbo | 85.9 gr | 80% | 39,262 psi | 59% | 3081 fps | 98.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,413 psi | 43% | 1978 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 49,559 psi | 74% | 3150 fps | 98.6% |
| IMR 7828 SSC | <<locked>> | 80% | 45,310 psi | 68% | 3146 fps | 98.1% |
| IMR 8133 Enduron | <<locked>> | 86% | 36,608 psi | 55% | 2940 fps | 95.7% |
| Lovex S071 | <<locked>> | 80% | 40,611 psi | 61% | 2943 fps | 99.6% |
| Norma 217 | <<locked>> | 82% | 32,126 psi | 48% | 2831 fps | 96% |
| Norma MRP | <<locked>> | 80% | 50,560 psi | 76% | 3248 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 45,890 psi | 69% | 3163 fps | 98.6% |
| Ramshot Magnum | <<locked>> | 80% | 41,539 psi | 62% | 3022 fps | 99% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,109 psi | 44% | 2024 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 38,943 psi | 58% | 3051 fps | 99.3% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 38,870 psi | 58% | 2999 fps | 95% |
| Rottweil R 904 | <<locked>> | 80% | 51,634 psi | 77% | 3199 fps | 99.2% |
| Rottweil R 905 | <<locked>> | 80% | 50,807 psi | 76% | 3212 fps | 99.7% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 48,370 psi | 73% | 3146 fps | 95.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 50,459 psi | 76% | 3209 fps | 99.7% |
| Somchem S361 | <<locked>> | 80% | 52,968 psi | 79% | 3182 fps | 99% |
| Somchem S385 | <<locked>> | 80% | 51,213 psi | 77% | 3179 fps | 99.9% |
| Vihtavuori N165 | <<locked>> | 80% | 44,788 psi | 67% | 3038 fps | 99.3% |
| Vihtavuori N170 | <<locked>> | 88% | 50,923 psi | 76% | 3176 fps | 95.3% |
| Vihtavuori N555 | <<locked>> | 80% | 50,807 psi | 76% | 3186 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 49,995 psi | 75% | 3245 fps | 98.6% |
| Vihtavuori N565 | <<locked>> | 80% | 41,785 psi | 63% | 3038 fps | 96.9% |
| Vihtavuori N568 | <<locked>> | 84% | 42,859 psi | 64% | 3097 fps | 95.9% |
| Vihtavuori N570 | 98.1 gr | 88% | 47,384 psi | 71% | 3232 fps | 95.3% |
| Winchester StaBALL HD | <<locked>> | 80% | 45,498 psi | 68% | 3166 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 47,384 psi | 71% | 3104 fps | 99.3% |
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 58 powders for 7.21 Firebird loaded with the .284 | 130gr | Speer Boat-Tail. ADI AR 2218 delivers the highest muzzle velocity at 3,484 fps; across all powders the maximum-charge window runs from 2,205 fps to 3,484 fps. Accurate 8700 gives the best case fill at 100 %, and 58 of the 58 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 130.0 gr projectile in 0.284" calls for a 1:13.5 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. Hodgdon Retumbo, ADI AR 2218, Vihtavuori N570 rank at the top here: for 7.21 Firebird with the .284 | 130gr | Speer Boat-Tail they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon US 869, Lovex D100, Ramshot LRT 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.