Load Specifications
Load data in caliber 7.21 Firebird with .284 | 132gr | Peregrine VLR-4 bullet and 59 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 ReloadSwiss RS 80.
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% | 58,334 psi | 87% | 3255 fps | 100% |
| Accurate MAGPRO | <<locked>> | 86% | 57,740 psi | 87% | 3376 fps | 99.3% |
| ADI AR 2209 | <<locked>> | 86% | 59,625 psi | 89% | 3363 fps | 100% |
| ADI AR 2213 | <<locked>> | 88% | 58,363 psi | 87% | 3376 fps | 99.8% |
| ADI AR 2217 | <<locked>> | 96% | 57,566 psi | 86% | 3350 fps | 99.9% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 58,784 psi | 88% | 3481 fps | 98.8% |
| ADI AR 2225 | <<locked>> | 98% | 56,869 psi | 85% | 3369 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 59,582 psi | 89% | 3346 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 59,103 psi | 89% | 3346 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 88% | 58,653 psi | 88% | 3366 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 56,710 psi | 85% | 3264 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 57,551 psi | 86% | 3343 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 57,638 psi | 86% | 3356 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 56,101 psi | 84% | 3373 fps | 98% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 55,854 psi | 84% | 3353 fps | 97.5% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 58,943 psi | 88% | 3327 fps | 98.6% |
| Bofors RP15 | <<locked>> | 90% | 58,001 psi | 87% | 3353 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 57,203 psi | 86% | 3356 fps | 99.9% |
| Bofors RP5 | <<locked>> | 88% | 58,653 psi | 88% | 3366 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 59,321 psi | 89% | 3376 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 57,290 psi | 86% | 3304 fps | 99.5% |
| Hodgdon H4831 SC | <<locked>> | 88% | 60,017 psi | 90% | 3350 fps | 99.7% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 59,698 psi | 89% | 3255 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 56,855 psi | 85% | 3438 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,666 psi | 56% | 2175 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 57,812 psi | 87% | 3271 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 58,566 psi | 88% | 3271 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 57,290 psi | 86% | 3278 fps | 99.6% |
| IMR 7828 SSC | <<locked>> | 88% | 56,855 psi | 85% | 3360 fps | 99.8% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 55,419 psi | 83% | 3337 fps | 99.8% |
| Lovex S070 | <<locked>> | 82% | 59,872 psi | 90% | 3301 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 60,104 psi | 90% | 3281 fps | 100% |
| Norma 204 | <<locked>> | 82% | 59,466 psi | 89% | 3337 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 56,840 psi | 85% | 3363 fps | 100% |
| Norma MRP | <<locked>> | 86% | 59,117 psi | 89% | 3386 fps | 100% |
| Norma URP | <<locked>> | 82% | 60,147 psi | 90% | 3317 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 58,276 psi | 87% | 3379 fps | 99.9% |
| Ramshot Hunter | <<locked>> | 82% | 59,466 psi | 89% | 3330 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 56,753 psi | 85% | 3297 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,508 psi | 58% | 2221 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 58,305 psi | 87% | 3422 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 57,363 psi | 86% | 3379 fps | 99.5% |
| Rottweil R 904 | <<locked>> | 86% | 60,017 psi | 90% | 3327 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 86% | 58,798 psi | 88% | 3337 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 59,872 psi | 90% | 3301 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 60,336 psi | 90% | 3248 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 58,407 psi | 88% | 3330 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 57,769 psi | 87% | 3248 fps | 99.5% |
| Somchem S365 | <<locked>> | 82% | 58,146 psi | 87% | 3261 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 59,219 psi | 89% | 3301 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 59,335 psi | 89% | 3284 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 58,842 psi | 88% | 3307 fps | 97.1% |
| Vihtavuori N555 | <<locked>> | 86% | 58,305 psi | 87% | 3297 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 58,479 psi | 88% | 3389 fps | 99.7% |
| Vihtavuori N565 | <<locked>> | 92% | 59,451 psi | 89% | 3373 fps | 99.8% |
| Vihtavuori N568 | <<locked>> | 94% | 57,537 psi | 86% | 3386 fps | 99.2% |
| Vihtavuori N570 | <<locked>> | 96% | 59,248 psi | 89% | 3458 fps | 98.2% |
| Winchester StaBALL HD | <<locked>> | 88% | 57,435 psi | 86% | 3356 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 59,321 psi | 89% | 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% | 44,121 psi | 66% | 3012 fps | 99.9% |
| Accurate MAGPRO | <<locked>> | 80% | 46,238 psi | 69% | 3153 fps | 97.3% |
| ADI AR 2209 | <<locked>> | 80% | 48,486 psi | 73% | 3163 fps | 99.4% |
| ADI AR 2213 | <<locked>> | 80% | 43,816 psi | 66% | 3097 fps | 97.7% |
| ADI AR 2217 | <<locked>> | 84% | 37,275 psi | 56% | 2930 fps | 96.1% |
| ADI AR 2218 | <<locked>> | 94% | 46,528 psi | 70% | 3225 fps | 95.5% |
| ADI AR 2225 | <<locked>> | 80% | 29,617 psi | 44% | 2743 fps | 95.6% |
| Alliant Reloder-16 | <<locked>> | 80% | 55,709 psi | 84% | 3284 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 48,414 psi | 73% | 3156 fps | 99.4% |
| Alliant Reloder-22 | <<locked>> | 80% | 44,498 psi | 67% | 3100 fps | 98.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 43,105 psi | 65% | 3031 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 37,318 psi | 56% | 2956 fps | 99.6% |
| Alliant Reloder-26 | <<locked>> | 80% | 49,385 psi | 74% | 3219 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 48,051 psi | 72% | 3215 fps | 96% |
| Alliant Reloder-50 | <<locked>> | 96% | 47,761 psi | 72% | 3192 fps | 95.3% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 45,136 psi | 68% | 3064 fps | 95.4% |
| Bofors RP15 | <<locked>> | 80% | 41,278 psi | 62% | 3025 fps | 98% |
| Bofors RP30 | <<locked>> | 80% | 34,751 psi | 52% | 2871 fps | 95% |
| Bofors RP5 | <<locked>> | 80% | 44,498 psi | 67% | 3100 fps | 98.8% |
| Hodgdon H1000 | <<locked>> | 80% | 35,302 psi | 53% | 2881 fps | 95.9% |
| Hodgdon H4831 | <<locked>> | 80% | 46,311 psi | 69% | 3097 fps | 97.8% |
| Hodgdon H4831 SC | <<locked>> | 80% | 45,527 psi | 68% | 3081 fps | 97.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 52,228 psi | 78% | 3143 fps | 100% |
| Hodgdon Retumbo | 82.5 gr | 80% | 36,419 psi | 55% | 2999 fps | 97.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,253 psi | 42% | 1952 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 54,085 psi | 81% | 3212 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 54,650 psi | 82% | 3212 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 47,108 psi | 71% | 3087 fps | 98.1% |
| IMR 7828 SSC | <<locked>> | 80% | 42,438 psi | 64% | 3071 fps | 97.4% |
| IMR 8133 Enduron | <<locked>> | 88% | 36,187 psi | 54% | 2923 fps | 95.5% |
| Lovex S070 | <<locked>> | 80% | 56,159 psi | 84% | 3245 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 37,739 psi | 57% | 2867 fps | 99.1% |
| Norma 204 | <<locked>> | 80% | 55,303 psi | 83% | 3268 fps | 99.9% |
| Norma 217 | <<locked>> | 84% | 31,604 psi | 47% | 2812 fps | 95.8% |
| Norma MRP | <<locked>> | 80% | 47,384 psi | 71% | 3179 fps | 99.8% |
| Norma URP | <<locked>> | 80% | 56,318 psi | 84% | 3261 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 42,714 psi | 64% | 3087 fps | 97.8% |
| Ramshot Hunter | <<locked>> | 80% | 55,390 psi | 83% | 3264 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 38,421 psi | 58% | 2940 fps | 98.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,921 psi | 43% | 1998 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 35,926 psi | 54% | 2966 fps | 98.4% |
| ReloadSwiss RS 80 | 95.7 gr | 86% | 41,785 psi | 63% | 3068 fps | 96.2% |
| Rottweil R 904 | <<locked>> | 80% | 49,139 psi | 74% | 3136 fps | 98.8% |
| Rottweil R 905 | <<locked>> | 80% | 47,877 psi | 72% | 3143 fps | 99.4% |
| Shooters World SW4350 | <<locked>> | 80% | 56,159 psi | 84% | 3245 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 56,362 psi | 84% | 3189 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 47,543 psi | 71% | 3136 fps | 99.3% |
| Somchem S361 | <<locked>> | 80% | 50,314 psi | 75% | 3120 fps | 98.6% |
| Somchem S365 | <<locked>> | 80% | 54,143 psi | 81% | 3202 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 48,370 psi | 73% | 3114 fps | 99.8% |
| Vihtavuori N165 | <<locked>> | 80% | 42,250 psi | 63% | 2972 fps | 98.8% |
| Vihtavuori N170 | <<locked>> | 90% | 51,111 psi | 77% | 3166 fps | 95.2% |
| Vihtavuori N555 | <<locked>> | 80% | 47,674 psi | 71% | 3120 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 47,007 psi | 70% | 3173 fps | 98% |
| Vihtavuori N565 | <<locked>> | 80% | 38,870 psi | 58% | 2956 fps | 95.8% |
| Vihtavuori N568 | <<locked>> | 86% | 42,714 psi | 64% | 3087 fps | 95.9% |
| Vihtavuori N570 | 96.3 gr | 90% | 47,195 psi | 71% | 3222 fps | 95.2% |
| Winchester StaBALL HD | <<locked>> | 80% | 41,814 psi | 63% | 3091 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 44,585 psi | 67% | 3035 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 59 powders for 7.21 Firebird loaded with the .284 | 132gr | Peregrine VLR-4. ADI AR 2218 delivers the highest muzzle velocity at 3,481 fps; across all powders the maximum-charge window runs from 2,175 fps to 3,481 fps. ADI AR 2218 gives the best case fill at 100 %, and 59 of the 59 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 132.0 gr projectile in 0.284" calls for a 1:9.5 twist; slower twists will usually not stabilise this weight. ADI AR 2218, 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, Vihtavuori N570, ReloadSwiss RS 80 rank at the top here: for 7.21 Firebird with the .284 | 132gr | Peregrine VLR-4 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.