Load Specifications
Load data in caliber 7.21 Firebird with .284 | 120gr | Barnes TTSX BT bullet and 66 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, Vihtavuori N570 and IMR 7828 SSC.
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>> | 90% | 59,553 psi | 89% | 3392 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 59,350 psi | 89% | 3422 fps | 100% |
| Accurate MAGPRO | <<locked>> | 88% | 59,030 psi | 88% | 3510 fps | 99% |
| ADI AR 2209 | <<locked>> | 86% | 56,942 psi | 85% | 3435 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 90% | 59,727 psi | 90% | 3514 fps | 99.7% |
| ADI AR 2217 | <<locked>> | 98% | 58,595 psi | 88% | 3478 fps | 99.8% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 55,506 psi | 83% | 3517 fps | 97.3% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 57,392 psi | 86% | 3494 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 56,826 psi | 85% | 3432 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 56,521 psi | 85% | 3422 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 90% | 59,959 psi | 90% | 3507 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 90% | 57,595 psi | 86% | 3399 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 58,349 psi | 87% | 3474 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 58,813 psi | 88% | 3494 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 57,058 psi | 86% | 3497 fps | 97.5% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 56,594 psi | 85% | 3392 fps | 97.5% |
| Bofors RP15 | <<locked>> | 92% | 59,045 psi | 89% | 3488 fps | 99.9% |
| Bofors RP30 | <<locked>> | 96% | 58,102 psi | 87% | 3484 fps | 99.8% |
| Bofors RP5 | <<locked>> | 90% | 59,959 psi | 90% | 3507 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 56,014 psi | 84% | 3435 fps | 99.8% |
| Hodgdon H4831 | <<locked>> | 88% | 58,610 psi | 88% | 3438 fps | 99.2% |
| Hodgdon H4831 SC | <<locked>> | 88% | 57,435 psi | 86% | 3415 fps | 99.1% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 57,043 psi | 86% | 3340 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 57,551 psi | 86% | 3573 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,463 psi | 56% | 2267 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 59,248 psi | 89% | 3412 fps | 100% |
| IMR 4831 | <<locked>> | 84% | 59,886 psi | 90% | 3415 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 58,769 psi | 88% | 3415 fps | 99.3% |
| IMR 7828 SSC | <<locked>> | 90% | 57,928 psi | 87% | 3491 fps | 99.5% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 52,301 psi | 78% | 3392 fps | 99.1% |
| Lovex S065 | <<locked>> | 82% | 58,972 psi | 88% | 3386 fps | 100% |
| Lovex S070 | <<locked>> | 82% | 57,421 psi | 86% | 3383 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 57,203 psi | 86% | 3356 fps | 100% |
| Norma 204 | <<locked>> | 82% | 56,753 psi | 85% | 3412 fps | 99.7% |
| Norma 217ᴾ | <<locked>> | 100% | 53,403 psi | 80% | 3419 fps | 100% |
| Norma MRP | <<locked>> | 88% | 60,336 psi | 90% | 3524 fps | 100% |
| Norma URP | <<locked>> | 82% | 57,508 psi | 86% | 3402 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 59,393 psi | 89% | 3514 fps | 99.8% |
| Ramshot Hunter | <<locked>> | 82% | 56,695 psi | 85% | 3406 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 58,146 psi | 87% | 3432 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,392 psi | 58% | 2320 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 60,017 psi | 90% | 3445 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 58,987 psi | 88% | 3478 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 59,190 psi | 89% | 3556 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 58,465 psi | 88% | 3510 fps | 99.2% |
| Rottweil R 904 | <<locked>> | 86% | 57,392 psi | 86% | 3399 fps | 99.4% |
| Rottweil R 905 | <<locked>> | 88% | 60,176 psi | 90% | 3478 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 82% | 58,972 psi | 88% | 3386 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 57,421 psi | 86% | 3383 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 57,972 psi | 87% | 3330 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 59,770 psi | 90% | 3471 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 59,248 psi | 89% | 3386 fps | 99.3% |
| Somchem S365 | <<locked>> | 84% | 59,321 psi | 89% | 3406 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 56,565 psi | 85% | 3373 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 59,059 psi | 89% | 3389 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 56,753 psi | 85% | 3356 fps | 100% |
| Vihtavuori N170 | <<locked>> | 96% | 60,336 psi | 90% | 3435 fps | 96.5% |
| Vihtavuori N550 | <<locked>> | 82% | 58,436 psi | 88% | 3392 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 59,335 psi | 89% | 3432 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 59,698 psi | 89% | 3527 fps | 99.4% |
| Vihtavuori N565 | <<locked>> | 92% | 56,565 psi | 85% | 3438 fps | 99.3% |
| Vihtavuori N568 | <<locked>> | 96% | 58,610 psi | 88% | 3514 fps | 98.8% |
| Vihtavuori N570 | <<locked>> | 98% | 60,017 psi | 90% | 3579 fps | 97.6% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 59,059 psi | 89% | 3327 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 90% | 58,117 psi | 87% | 3494 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 56,739 psi | 85% | 3373 fps | 99.8% |
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% | 41,843 psi | 63% | 3071 fps | 99.3% |
| Accurate 4350 | <<locked>> | 80% | 55,477 psi | 83% | 3363 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 43,772 psi | 66% | 3202 fps | 95.6% |
| ADI AR 2209 | <<locked>> | 80% | 46,195 psi | 69% | 3228 fps | 98.4% |
| ADI AR 2213 | <<locked>> | 80% | 41,510 psi | 62% | 3146 fps | 96.1% |
| ADI AR 2217 | <<locked>> | 86% | 37,884 psi | 57% | 3041 fps | 95.2% |
| ADI AR 2218 | <<locked>> | 98% | 51,372 psi | 77% | 3432 fps | 96.1% |
| ADI AR 2225 | <<locked>> | 84% | 32,227 psi | 48% | 2917 fps | 95.9% |
| Alliant Reloder-16 | <<locked>> | 80% | 53,127 psi | 80% | 3369 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 46,180 psi | 69% | 3219 fps | 98.5% |
| Alliant Reloder-22 | <<locked>> | 80% | 42,134 psi | 63% | 3153 fps | 97.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,799 psi | 61% | 3097 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 35,143 psi | 53% | 3002 fps | 98.6% |
| Alliant Reloder-26 | <<locked>> | 80% | 46,485 psi | 70% | 3278 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 48,704 psi | 73% | 3330 fps | 95.2% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 49,443 psi | 74% | 3258 fps | 95.8% |
| Bofors RP15 | <<locked>> | 80% | 39,117 psi | 59% | 3074 fps | 96.5% |
| Bofors RP30 | <<locked>> | 84% | 37,768 psi | 57% | 3054 fps | 95.3% |
| Bofors RP5 | <<locked>> | 80% | 42,134 psi | 63% | 3153 fps | 97.6% |
| Hodgdon H1000 | <<locked>> | 82% | 35,926 psi | 54% | 2992 fps | 95% |
| Hodgdon H4831 | <<locked>> | 80% | 44,077 psi | 66% | 3153 fps | 96.3% |
| Hodgdon H4831 SC | <<locked>> | 80% | 43,323 psi | 65% | 3136 fps | 96.1% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,850 psi | 75% | 3225 fps | 100% |
| Hodgdon Retumbo | 83.7 gr | 80% | 34,258 psi | 51% | 3028 fps | 95.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,065 psi | 42% | 2041 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 51,837 psi | 78% | 3287 fps | 99.8% |
| IMR 4831 | <<locked>> | 80% | 52,214 psi | 78% | 3291 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 45,121 psi | 68% | 3150 fps | 96.8% |
| IMR 7828 SSC | 83.6 gr | 80% | 40,074 psi | 60% | 3120 fps | 95.6% |
| IMR 8133 Enduron | <<locked>> | 92% | 39,247 psi | 59% | 3100 fps | 95.7% |
| Lovex S065 | <<locked>> | 80% | 55,376 psi | 83% | 3327 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 53,882 psi | 81% | 3323 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 35,650 psi | 53% | 2917 fps | 97.9% |
| Norma 204 | <<locked>> | 80% | 52,953 psi | 79% | 3340 fps | 99.4% |
| Norma 217 | <<locked>> | 88% | 34,171 psi | 51% | 2986 fps | 96% |
| Norma MRP | <<locked>> | 80% | 44,860 psi | 67% | 3235 fps | 99.2% |
| Norma URP | <<locked>> | 80% | 53,867 psi | 81% | 3343 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 40,190 psi | 60% | 3130 fps | 96.1% |
| Ramshot Hunter | <<locked>> | 80% | 52,997 psi | 79% | 3343 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 36,114 psi | 54% | 2982 fps | 96.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,689 psi | 43% | 2083 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 55,854 psi | 84% | 3383 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 54,766 psi | 82% | 3412 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 33,707 psi | 51% | 2992 fps | 96.5% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 42,482 psi | 64% | 3182 fps | 95.4% |
| Rottweil R 904 | <<locked>> | 80% | 47,021 psi | 70% | 3202 fps | 97.8% |
| Rottweil R 905 | <<locked>> | 80% | 45,542 psi | 68% | 3202 fps | 98.4% |
| Shooters World Long Rifle | <<locked>> | 80% | 55,376 psi | 83% | 3327 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 53,882 psi | 81% | 3323 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 54,172 psi | 81% | 3268 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 45,223 psi | 68% | 3199 fps | 98.4% |
| Somchem S361 | <<locked>> | 80% | 48,182 psi | 72% | 3182 fps | 97.5% |
| Somchem S365 | <<locked>> | 80% | 51,474 psi | 77% | 3281 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 46,064 psi | 69% | 3176 fps | 99.1% |
| Vihtavuori N160 | <<locked>> | 80% | 55,347 psi | 83% | 3333 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 40,161 psi | 60% | 3031 fps | 97.6% |
| Vihtavuori N170 | <<locked>> | 94% | 56,144 psi | 84% | 3360 fps | 95.6% |
| Vihtavuori N550 | <<locked>> | 80% | 54,665 psi | 82% | 3333 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 45,078 psi | 68% | 3182 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 44,599 psi | 67% | 3228 fps | 96.5% |
| Vihtavuori N565 | <<locked>> | 82% | 39,494 psi | 59% | 3074 fps | 95.1% |
| Vihtavuori N568 | <<locked>> | 88% | 43,424 psi | 65% | 3205 fps | 95.1% |
| Vihtavuori N570 | 102.1 gr | 94% | 51,663 psi | 77% | 3422 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 55,085 psi | 83% | 3268 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 38,914 psi | 58% | 3143 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 42,540 psi | 64% | 3094 fps | 97.7% |
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 73 powders for 7.21 Firebird loaded with the .284 | 120gr | Barnes TTSX BT. Vihtavuori N570 delivers the highest muzzle velocity at 3,579 fps; across all powders the maximum-charge window runs from 2,267 fps to 3,579 fps. Accurate 8700 gives the best case fill at 100 %, and 73 of the 73 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 1:11.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, ADI AR 2218, ADI AR 2225 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, Vihtavuori N570, IMR 7828 SSC rank at the top here: for 7.21 Firebird with the .284 | 120gr | Barnes TTSX BT they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 8700, IMR 7977 Enduron, Lovex D100 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.