Load Specifications
Load data in caliber 7.21 Firebird with .284 | 120gr | Barnes TSX BT bullet and 64 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N570, Hodgdon Retumbo and ReloadSwiss RS 76.
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>> | 88% | 56,376 psi | 85% | 3343 fps | 100% |
| Accurate MAGPRO | <<locked>> | 88% | 59,872 psi | 90% | 3524 fps | 99.2% |
| ADI AR 2209 | <<locked>> | 86% | 57,841 psi | 87% | 3451 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 88% | 56,449 psi | 85% | 3458 fps | 99.4% |
| ADI AR 2217 | <<locked>> | 98% | 59,640 psi | 89% | 3491 fps | 99.9% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 56,492 psi | 85% | 3537 fps | 97.6% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 58,653 psi | 88% | 3507 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 57,653 psi | 86% | 3442 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 57,377 psi | 86% | 3435 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 88% | 56,811 psi | 85% | 3451 fps | 99.9% |
| Alliant Reloder-23 | <<locked>> | 90% | 58,508 psi | 88% | 3412 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 59,451 psi | 89% | 3491 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 59,944 psi | 90% | 3510 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 58,407 psi | 88% | 3514 fps | 97.8% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 53,780 psi | 81% | 3412 fps | 96.2% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 57,392 psi | 86% | 3409 fps | 97.7% |
| Bofors RP15 | <<locked>> | 92% | 60,104 psi | 90% | 3504 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 59,117 psi | 89% | 3501 fps | 99.8% |
| Bofors RP5 | <<locked>> | 88% | 56,811 psi | 85% | 3451 fps | 99.9% |
| Hodgdon H1000 | <<locked>> | 94% | 57,043 psi | 86% | 3451 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 88% | 59,408 psi | 89% | 3451 fps | 99.3% |
| Hodgdon H4831 SC | <<locked>> | 88% | 58,276 psi | 87% | 3432 fps | 99.2% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 57,798 psi | 87% | 3350 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 58,726 psi | 88% | 3589 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,420 psi | 56% | 2270 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 59,886 psi | 90% | 3422 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 56,681 psi | 85% | 3363 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 59,524 psi | 89% | 3425 fps | 99.4% |
| IMR 7828 SSC | <<locked>> | 90% | 58,798 psi | 88% | 3504 fps | 99.6% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 53,432 psi | 80% | 3409 fps | 99.3% |
| Lovex S065 | <<locked>> | 82% | 59,669 psi | 89% | 3396 fps | 100% |
| Lovex S070 | <<locked>> | 82% | 58,102 psi | 87% | 3392 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 58,059 psi | 87% | 3366 fps | 100% |
| Norma 204 | <<locked>> | 82% | 57,624 psi | 86% | 3425 fps | 99.8% |
| Norma 217ᴾ | <<locked>> | 100% | 54,462 psi | 82% | 3435 fps | 100% |
| Norma MRP | <<locked>> | 86% | 56,927 psi | 85% | 3465 fps | 100% |
| Norma URP | <<locked>> | 82% | 58,291 psi | 87% | 3415 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 56,028 psi | 84% | 3458 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 82% | 57,595 psi | 86% | 3422 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 59,176 psi | 89% | 3445 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,348 psi | 57% | 2323 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 59,930 psi | 90% | 3494 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 55,767 psi | 84% | 3497 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 59,640 psi | 89% | 3527 fps | 99.4% |
| Rottweil R 904 | <<locked>> | 86% | 58,233 psi | 87% | 3415 fps | 99.5% |
| Rottweil R 905 | <<locked>> | 86% | 57,014 psi | 85% | 3425 fps | 99.9% |
| Shooters World Long Rifle | <<locked>> | 82% | 59,669 psi | 89% | 3396 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 58,102 psi | 87% | 3392 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 58,784 psi | 88% | 3343 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 56,623 psi | 85% | 3419 fps | 99.8% |
| Somchem S361 | <<locked>> | 86% | 60,118 psi | 90% | 3396 fps | 99.4% |
| Somchem S365 | <<locked>> | 84% | 60,133 psi | 90% | 3415 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 57,406 psi | 86% | 3389 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 59,988 psi | 90% | 3406 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 57,522 psi | 86% | 3369 fps | 100% |
| Vihtavuori N550 | <<locked>> | 82% | 59,292 psi | 89% | 3406 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 60,263 psi | 90% | 3445 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 56,362 psi | 84% | 3468 fps | 99.1% |
| Vihtavuori N565 | <<locked>> | 92% | 57,551 psi | 86% | 3455 fps | 99.4% |
| Vihtavuori N568 | <<locked>> | 96% | 59,799 psi | 90% | 3530 fps | 99% |
| Vihtavuori N570 | <<locked>> | 96% | 56,797 psi | 85% | 3520 fps | 97% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 60,046 psi | 90% | 3340 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 90% | 59,408 psi | 89% | 3507 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 57,508 psi | 86% | 3383 fps | 99.9% |
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% | 42,525 psi | 64% | 3081 fps | 99.4% |
| Accurate MAGPRO | <<locked>> | 80% | 44,570 psi | 67% | 3219 fps | 95.9% |
| ADI AR 2209 | <<locked>> | 80% | 46,891 psi | 70% | 3238 fps | 98.6% |
| ADI AR 2213 | <<locked>> | 80% | 42,163 psi | 63% | 3159 fps | 96.4% |
| ADI AR 2217 | <<locked>> | 86% | 38,580 psi | 58% | 3058 fps | 95.6% |
| ADI AR 2218 | <<locked>> | 96% | 48,341 psi | 72% | 3360 fps | 95.1% |
| ADI AR 2225 | <<locked>> | 84% | 32,866 psi | 49% | 2936 fps | 96.3% |
| Alliant Reloder-16 | <<locked>> | 80% | 53,969 psi | 81% | 3383 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 46,833 psi | 70% | 3232 fps | 98.6% |
| Alliant Reloder-22 | <<locked>> | 80% | 42,830 psi | 64% | 3166 fps | 97.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 41,394 psi | 62% | 3107 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 35,781 psi | 54% | 3018 fps | 98.8% |
| Alliant Reloder-26 | <<locked>> | 80% | 47,427 psi | 71% | 3294 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 49,777 psi | 75% | 3346 fps | 95.6% |
| Alliant Reloder-50 | <<locked>> | 98% | 49,603 psi | 74% | 3327 fps | 95% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 46,818 psi | 70% | 3202 fps | 95.1% |
| Bofors RP15 | <<locked>> | 80% | 39,639 psi | 59% | 3087 fps | 96.7% |
| Bofors RP30 | <<locked>> | 84% | 38,522 psi | 58% | 3071 fps | 95.6% |
| Bofors RP5 | <<locked>> | 80% | 42,830 psi | 64% | 3166 fps | 97.8% |
| Hodgdon H1000 | <<locked>> | 82% | 36,506 psi | 55% | 3005 fps | 95.4% |
| Hodgdon H4831 | <<locked>> | 80% | 44,701 psi | 67% | 3166 fps | 96.5% |
| Hodgdon H4831 SC | <<locked>> | 80% | 43,976 psi | 66% | 3150 fps | 96.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 50,459 psi | 76% | 3232 fps | 100% |
| Hodgdon Retumbo | 84.8 gr | 80% | 34,867 psi | 52% | 3045 fps | 95.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,007 psi | 42% | 2041 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 52,518 psi | 79% | 3297 fps | 99.8% |
| IMR 4831 | <<locked>> | 80% | 52,968 psi | 79% | 3301 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 45,730 psi | 69% | 3163 fps | 97% |
| IMR 7828 SSC | <<locked>> | 80% | 40,756 psi | 61% | 3133 fps | 95.9% |
| IMR 8133 Enduron | <<locked>> | 92% | 40,016 psi | 60% | 3117 fps | 96.1% |
| Lovex S065 | <<locked>> | 80% | 55,912 psi | 84% | 3337 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 54,418 psi | 82% | 3333 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 36,318 psi | 54% | 2933 fps | 98.1% |
| Norma 204 | <<locked>> | 80% | 53,664 psi | 80% | 3353 fps | 99.5% |
| Norma 217 | <<locked>> | 86% | 32,372 psi | 49% | 2927 fps | 95% |
| Norma MRP | <<locked>> | 80% | 45,585 psi | 68% | 3248 fps | 99.3% |
| Norma URP | <<locked>> | 80% | 54,447 psi | 82% | 3350 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 40,901 psi | 61% | 3146 fps | 96.5% |
| Ramshot Hunter | <<locked>> | 80% | 53,722 psi | 81% | 3353 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 36,767 psi | 55% | 2995 fps | 96.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,761 psi | 43% | 2090 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 55,695 psi | 83% | 3425 fps | 100% |
| ReloadSwiss RS 76 | 90.8 gr | 80% | 34,403 psi | 52% | 3012 fps | 96.9% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 43,381 psi | 65% | 3202 fps | 95.8% |
| Rottweil R 904 | <<locked>> | 80% | 47,674 psi | 71% | 3215 fps | 98% |
| Rottweil R 905 | <<locked>> | 80% | 46,253 psi | 69% | 3215 fps | 98.6% |
| Shooters World Long Rifle | <<locked>> | 80% | 55,912 psi | 84% | 3337 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 54,418 psi | 82% | 3333 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 54,839 psi | 82% | 3278 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 45,919 psi | 69% | 3212 fps | 98.6% |
| Somchem S361 | <<locked>> | 80% | 48,892 psi | 73% | 3196 fps | 97.7% |
| Somchem S365 | <<locked>> | 80% | 52,286 psi | 78% | 3294 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 46,717 psi | 70% | 3192 fps | 99.2% |
| Vihtavuori N160 | <<locked>> | 80% | 56,086 psi | 84% | 3343 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 40,785 psi | 61% | 3041 fps | 97.8% |
| Vihtavuori N550 | <<locked>> | 80% | 55,376 psi | 83% | 3343 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 45,861 psi | 69% | 3199 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 45,281 psi | 68% | 3238 fps | 96.8% |
| Vihtavuori N565 | <<locked>> | 82% | 40,147 psi | 60% | 3087 fps | 95.4% |
| Vihtavuori N568 | <<locked>> | 88% | 44,208 psi | 66% | 3219 fps | 95.4% |
| Vihtavuori N570 | 103.4 gr | 94% | 52,649 psi | 79% | 3442 fps | 96% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 55,883 psi | 84% | 3278 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 39,755 psi | 60% | 3156 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 43,149 psi | 65% | 3104 fps | 97.9% |
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 64 powders for 7.21 Firebird loaded with the .284 | 120gr | Barnes TSX BT. Hodgdon Retumbo delivers the highest muzzle velocity at 3,589 fps; across all powders the maximum-charge window runs from 2,270 fps to 3,589 fps. ADI AR 2218 gives the best case fill at 100 %, and 64 of the 64 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (460 MPa), the top charges use 56–90 %, leaving at least 10 % headroom. The 120.0 gr projectile in 0.284" calls for a 1:11.5 twist; slower twists will usually not stabilise this weight. ADI AR 2218, ADI AR 2225, Alliant Reloder-50 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. Vihtavuori N570, Hodgdon Retumbo, ReloadSwiss RS 76 rank at the top here: for 7.21 Firebird with the .284 | 120gr | Barnes TSX BT 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.