Load Specifications
Load data in caliber 7.21 Firebird with .284 | 123gr | RWS Kegelspitz bullet and 52 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.
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Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 88% | 59,988 psi | 90% | 3360 fps | 100% |
| Accurate MAGPRO | <<locked>> | 86% | 59,335 psi | 89% | 3481 fps | 99.3% |
| ADI AR 2209 | <<locked>> | 84% | 57,043 psi | 86% | 3402 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 88% | 59,886 psi | 90% | 3481 fps | 99.8% |
| ADI AR 2217 | <<locked>> | 96% | 59,176 psi | 89% | 3451 fps | 99.9% |
| ADI AR 2218 | <<locked>> | 98% | 56,072 psi | 84% | 3501 fps | 97.9% |
| ADI AR 2225 | <<locked>> | 98% | 58,552 psi | 88% | 3468 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 56,492 psi | 85% | 3386 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 88% | 60,307 psi | 90% | 3471 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 58,247 psi | 87% | 3366 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 59,117 psi | 89% | 3445 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 59,495 psi | 89% | 3465 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 58,291 psi | 87% | 3481 fps | 98% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 58,494 psi | 88% | 3468 fps | 97.6% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 60,118 psi | 90% | 3425 fps | 98.5% |
| Bofors RP15 | <<locked>> | 90% | 59,495 psi | 89% | 3458 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 59,074 psi | 89% | 3465 fps | 99.9% |
| Bofors RP5 | <<locked>> | 88% | 60,307 psi | 90% | 3471 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 56,536 psi | 85% | 3406 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 86% | 58,479 psi | 88% | 3402 fps | 99.4% |
| Hodgdon H4831 SC | <<locked>> | 86% | 57,421 psi | 86% | 3383 fps | 99.3% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 57,000 psi | 85% | 3301 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 58,610 psi | 88% | 3547 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,782 psi | 57% | 2257 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 58,813 psi | 88% | 3373 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 59,828 psi | 90% | 3373 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 58,523 psi | 88% | 3379 fps | 99.5% |
| IMR 7828 SSC | <<locked>> | 88% | 58,117 psi | 87% | 3458 fps | 99.7% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 57,479 psi | 86% | 3445 fps | 99.8% |
| Lovex S071 | <<locked>> | 92% | 58,088 psi | 87% | 3333 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 58,987 psi | 88% | 3474 fps | 100% |
| Norma MRP | <<locked>> | 84% | 56,536 psi | 85% | 3422 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 59,886 psi | 90% | 3484 fps | 99.9% |
| Ramshot Magnum | <<locked>> | 90% | 58,552 psi | 88% | 3399 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,754 psi | 58% | 2310 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 60,133 psi | 90% | 3527 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 59,393 psi | 89% | 3484 fps | 99.5% |
| Rottweil R 904 | <<locked>> | 84% | 57,363 psi | 86% | 3366 fps | 99.6% |
| Rottweil R 905 | <<locked>> | 86% | 60,321 psi | 90% | 3442 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 59,930 psi | 90% | 3438 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 59,016 psi | 88% | 3350 fps | 99.5% |
| Somchem S365 | <<locked>> | 82% | 59,480 psi | 89% | 3366 fps | 100% |
| Somchem S385 | <<locked>> | 84% | 56,710 psi | 85% | 3340 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 56,826 psi | 85% | 3323 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 56,492 psi | 85% | 3340 fps | 96.2% |
| Vihtavuori N555 | <<locked>> | 86% | 59,959 psi | 90% | 3402 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 59,857 psi | 90% | 3494 fps | 99.6% |
| Vihtavuori N565 | <<locked>> | 90% | 57,246 psi | 86% | 3412 fps | 99.5% |
| Vihtavuori N568 | <<locked>> | 94% | 59,495 psi | 89% | 3491 fps | 99.2% |
| Vihtavuori N570 | <<locked>> | 94% | 56,826 psi | 85% | 3484 fps | 97.3% |
| Winchester StaBALL HD | <<locked>> | 88% | 59,379 psi | 89% | 3465 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 56,724 psi | 85% | 3337 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% | 45,730 psi | 69% | 3117 fps | 99.9% |
| Accurate MAGPRO | <<locked>> | 80% | 47,805 psi | 72% | 3258 fps | 97.2% |
| ADI AR 2209 | <<locked>> | 80% | 49,705 psi | 75% | 3264 fps | 99.3% |
| ADI AR 2213 | <<locked>> | 80% | 44,962 psi | 67% | 3192 fps | 97.5% |
| ADI AR 2217 | <<locked>> | 84% | 38,595 psi | 58% | 3028 fps | 96% |
| ADI AR 2218 | <<locked>> | 94% | 48,254 psi | 72% | 3327 fps | 95.5% |
| ADI AR 2225 | <<locked>> | 80% | 30,850 psi | 46% | 2841 fps | 95.6% |
| Alliant Reloder-19 | <<locked>> | 80% | 49,603 psi | 74% | 3255 fps | 99.3% |
| Alliant Reloder-22 | <<locked>> | 80% | 45,788 psi | 69% | 3202 fps | 98.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 44,454 psi | 67% | 3133 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 38,667 psi | 58% | 3054 fps | 99.6% |
| Alliant Reloder-26 | <<locked>> | 80% | 51,126 psi | 77% | 3327 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 49,879 psi | 75% | 3320 fps | 96% |
| Alliant Reloder-50 | <<locked>> | 96% | 50,053 psi | 75% | 3304 fps | 95.5% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 46,180 psi | 69% | 3153 fps | 95.2% |
| Bofors RP15 | <<locked>> | 80% | 42,496 psi | 64% | 3123 fps | 97.9% |
| Bofors RP30 | <<locked>> | 80% | 36,172 psi | 54% | 2972 fps | 95% |
| Bofors RP5 | <<locked>> | 80% | 45,788 psi | 69% | 3202 fps | 98.7% |
| Hodgdon H1000 | <<locked>> | 80% | 36,477 psi | 55% | 2976 fps | 95.8% |
| Hodgdon H4831 | <<locked>> | 80% | 47,398 psi | 71% | 3192 fps | 97.6% |
| Hodgdon H4831 SC | <<locked>> | 80% | 46,644 psi | 70% | 3176 fps | 97.4% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 53,476 psi | 80% | 3245 fps | 100% |
| Hodgdon Retumbo | 86.3 gr | 80% | 37,710 psi | 57% | 3097 fps | 97.4% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,268 psi | 42% | 2028 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 55,201 psi | 83% | 3310 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 56,057 psi | 84% | 3317 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 48,196 psi | 72% | 3182 fps | 97.9% |
| IMR 7828 SSC | <<locked>> | 80% | 43,656 psi | 65% | 3169 fps | 97.2% |
| IMR 8133 Enduron | <<locked>> | 88% | 37,768 psi | 57% | 3025 fps | 95.5% |
| Lovex S071 | <<locked>> | 80% | 39,262 psi | 59% | 2972 fps | 99.1% |
| Norma 217 | <<locked>> | 84% | 33,127 psi | 50% | 2913 fps | 95.8% |
| Norma MRP | <<locked>> | 80% | 48,921 psi | 73% | 3281 fps | 99.8% |
| Ramshot Grand | <<locked>> | 80% | 44,063 psi | 66% | 3186 fps | 97.7% |
| Ramshot Magnum | <<locked>> | 80% | 39,885 psi | 60% | 3041 fps | 98.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,066 psi | 44% | 2077 fps | 100% |
| ReloadSwiss RS 76 | 92.4 gr | 80% | 37,420 psi | 56% | 3068 fps | 98.4% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 40,306 psi | 60% | 3094 fps | 95% |
| Rottweil R 904 | <<locked>> | 80% | 50,169 psi | 75% | 3232 fps | 98.7% |
| Rottweil R 905 | <<locked>> | 80% | 49,197 psi | 74% | 3245 fps | 99.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 48,849 psi | 73% | 3238 fps | 99.2% |
| Somchem S361 | <<locked>> | 80% | 51,459 psi | 77% | 3215 fps | 98.5% |
| Somchem S365 | <<locked>> | 80% | 55,637 psi | 83% | 3310 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 49,661 psi | 74% | 3215 fps | 99.7% |
| Vihtavuori N165 | <<locked>> | 80% | 43,511 psi | 65% | 3074 fps | 98.7% |
| Vihtavuori N170 | <<locked>> | 90% | 52,794 psi | 79% | 3268 fps | 95.2% |
| Vihtavuori N555 | <<locked>> | 80% | 49,168 psi | 74% | 3225 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 48,399 psi | 73% | 3274 fps | 97.9% |
| Vihtavuori N565 | <<locked>> | 80% | 40,379 psi | 61% | 3061 fps | 95.9% |
| Vihtavuori N568 | <<locked>> | 86% | 44,382 psi | 67% | 3189 fps | 95.8% |
| Vihtavuori N570 | 100.8 gr | 90% | 48,979 psi | 73% | 3327 fps | 95.2% |
| Winchester StaBALL HD | <<locked>> | 80% | 43,453 psi | 65% | 3196 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 45,890 psi | 69% | 3133 fps | 98.8% |
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 52 powders for 7.21 Firebird loaded with the .284 | 123gr | RWS Kegelspitz. Hodgdon Retumbo delivers the highest muzzle velocity at 3,547 fps; across all powders the maximum-charge window runs from 2,257 fps to 3,547 fps. Alliant Reloder-50 gives the best case fill at 100 %, and 52 of the 52 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 123.0 gr projectile in 0.284" calls for a 1:14.5 twist; slower twists will usually not stabilise this weight. Alliant Reloder-50, Hodgdon TrailBoss, IMR 8133 Enduron 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 | 123gr | RWS Kegelspitz 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.