Load Specifications
Load data in caliber 7.21 Firebird with .284 | 140gr | Peregrine VRG-3 bullet and 52 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2218, Hodgdon Retumbo 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% | 58,247 psi | 87% | 3179 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 50,734 psi | 76% | 3140 fps | 97% |
| Accurate MAGPRO | <<locked>> | 84% | 57,870 psi | 87% | 3301 fps | 99.6% |
| ADI AR 2209 | <<locked>> | 84% | 59,451 psi | 89% | 3281 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 58,508 psi | 88% | 3304 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 58,189 psi | 87% | 3281 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 59,422 psi | 89% | 3422 fps | 99.3% |
| ADI AR 2225 | <<locked>> | 96% | 57,827 psi | 87% | 3297 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 58,958 psi | 88% | 3268 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 58,871 psi | 88% | 3291 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 56,869 psi | 85% | 3186 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 58,015 psi | 87% | 3268 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 58,015 psi | 87% | 3278 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 56,884 psi | 85% | 3310 fps | 98.6% |
| Alliant Reloder-50 | <<locked>> | 98% | 57,072 psi | 86% | 3301 fps | 98.3% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 58,856 psi | 88% | 3258 fps | 99% |
| Bofors RP15 | <<locked>> | 88% | 58,218 psi | 87% | 3281 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 57,783 psi | 87% | 3291 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 58,871 psi | 88% | 3291 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 59,712 psi | 90% | 3301 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 56,884 psi | 85% | 3225 fps | 99.7% |
| Hodgdon H4831 SC | <<locked>> | 86% | 59,915 psi | 90% | 3271 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 59,437 psi | 89% | 3173 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 57,740 psi | 87% | 3369 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,884 psi | 57% | 2129 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 56,927 psi | 85% | 3202 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 86% | 56,985 psi | 85% | 3284 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 92% | 59,625 psi | 89% | 3209 fps | 96.4% |
| IMR 8133 Enduron | <<locked>> | 98% | 56,492 psi | 85% | 3278 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 56,594 psi | 85% | 3156 fps | 100% |
| Norma 217 | <<locked>> | 98% | 58,073 psi | 87% | 3301 fps | 100% |
| Norma MRP | <<locked>> | 84% | 59,306 psi | 89% | 3307 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 58,726 psi | 88% | 3307 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 57,203 psi | 86% | 3225 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,899 psi | 58% | 2178 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 59,001 psi | 88% | 3350 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 57,972 psi | 87% | 3314 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 84% | 59,698 psi | 89% | 3248 fps | 100% |
| Rottweil R 905 | <<locked>> | 84% | 58,755 psi | 88% | 3258 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 52,460 psi | 79% | 3153 fps | 97% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 58,378 psi | 88% | 3255 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 57,217 psi | 86% | 3169 fps | 99.8% |
| Somchem S385 | <<locked>> | 84% | 59,059 psi | 89% | 3222 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 59,277 psi | 89% | 3209 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 58,827 psi | 88% | 3238 fps | 97.7% |
| Vihtavuori N555 | <<locked>> | 84% | 58,494 psi | 88% | 3219 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 58,552 psi | 88% | 3314 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 90% | 59,872 psi | 90% | 3304 fps | 100% |
| Vihtavuori N568 | <<locked>> | 92% | 58,291 psi | 87% | 3320 fps | 99.6% |
| Vihtavuori N570 | <<locked>> | 94% | 59,886 psi | 90% | 3392 fps | 98.8% |
| Winchester StaBALL HD | <<locked>> | 86% | 58,392 psi | 88% | 3284 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 59,190 psi | 89% | 3222 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% | 47,340 psi | 71% | 2999 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 46,963 psi | 70% | 3064 fps | 95.9% |
| Accurate MAGPRO | <<locked>> | 80% | 49,980 psi | 75% | 3159 fps | 98.7% |
| ADI AR 2209 | <<locked>> | 80% | 51,793 psi | 78% | 3153 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 47,152 psi | 71% | 3097 fps | 98.9% |
| ADI AR 2217 | <<locked>> | 80% | 34,954 psi | 52% | 2802 fps | 95.9% |
| ADI AR 2218 | 100.9 gr | 90% | 43,540 psi | 65% | 3091 fps | 95.3% |
| ADI AR 2225 | <<locked>> | 80% | 32,256 psi | 48% | 2766 fps | 97.8% |
| Alliant Reloder-19 | <<locked>> | 80% | 51,619 psi | 77% | 3143 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 47,790 psi | 72% | 3094 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 46,499 psi | 70% | 3018 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 40,611 psi | 61% | 2956 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 53,664 psi | 80% | 3209 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 88% | 45,136 psi | 68% | 3081 fps | 95.8% |
| Alliant Reloder-50 | <<locked>> | 92% | 45,107 psi | 68% | 3064 fps | 95.2% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 44,976 psi | 67% | 2995 fps | 96.2% |
| Bofors RP15 | <<locked>> | 80% | 44,425 psi | 67% | 3025 fps | 99.1% |
| Bofors RP30 | <<locked>> | 80% | 37,826 psi | 57% | 2884 fps | 97% |
| Bofors RP5 | <<locked>> | 80% | 47,790 psi | 72% | 3094 fps | 99.7% |
| Hodgdon H1000 | <<locked>> | 80% | 38,145 psi | 57% | 2890 fps | 97.8% |
| Hodgdon H4831 | <<locked>> | 80% | 49,588 psi | 74% | 3094 fps | 98.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 48,602 psi | 73% | 3074 fps | 98.8% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 55,695 psi | 83% | 3117 fps | 100% |
| Hodgdon Retumbo | 84.7 gr | 80% | 39,827 psi | 60% | 3015 fps | 99.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,413 psi | 43% | 1913 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 49,951 psi | 75% | 3074 fps | 99.1% |
| IMR 7828 SSC | <<locked>> | 80% | 45,977 psi | 69% | 3077 fps | 98.8% |
| IMR 7977 Enduron | <<locked>> | 90% | 55,782 psi | 84% | 3143 fps | 95.6% |
| IMR 8133 Enduron | <<locked>> | 84% | 34,374 psi | 52% | 2805 fps | 95.4% |
| Lovex S071 | <<locked>> | 80% | 40,567 psi | 61% | 2864 fps | 99.8% |
| Norma 217 | <<locked>> | 80% | 29,965 psi | 45% | 2690 fps | 95.6% |
| Norma MRP | <<locked>> | 80% | 51,300 psi | 77% | 3176 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 46,543 psi | 70% | 3091 fps | 99.1% |
| Ramshot Magnum | <<locked>> | 80% | 41,989 psi | 63% | 2949 fps | 99.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,109 psi | 44% | 1955 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 39,465 psi | 59% | 2986 fps | 99.7% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 39,160 psi | 59% | 2933 fps | 95.9% |
| Rottweil R 904 | <<locked>> | 80% | 52,214 psi | 78% | 3123 fps | 99.6% |
| Rottweil R 905 | <<locked>> | 80% | 51,387 psi | 77% | 3136 fps | 99.9% |
| SNPE Vectan SP 13 | <<locked>> | 96% | 45,469 psi | 68% | 3012 fps | 95% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 51,039 psi | 77% | 3130 fps | 99.9% |
| Somchem S361 | <<locked>> | 80% | 53,505 psi | 80% | 3107 fps | 99.4% |
| Somchem S385 | <<locked>> | 80% | 51,547 psi | 77% | 3100 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 45,237 psi | 68% | 2966 fps | 99.6% |
| Vihtavuori N170 | <<locked>> | 86% | 47,892 psi | 72% | 3035 fps | 95.1% |
| Vihtavuori N555 | <<locked>> | 80% | 51,213 psi | 77% | 3104 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 50,734 psi | 76% | 3176 fps | 99.2% |
| Vihtavuori N565 | <<locked>> | 80% | 42,119 psi | 63% | 2969 fps | 97.6% |
| Vihtavuori N568 | <<locked>> | 82% | 40,147 psi | 60% | 2956 fps | 95.7% |
| Vihtavuori N570 | 94.5 gr | 86% | 44,585 psi | 67% | 3091 fps | 95.1% |
| Winchester StaBALL HD | <<locked>> | 80% | 46,166 psi | 69% | 3087 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 47,805 psi | 72% | 3028 fps | 99.7% |
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 59 powders for 7.21 Firebird loaded with the .284 | 140gr | Peregrine VRG-3. ADI AR 2218 delivers the highest muzzle velocity at 3,422 fps; across all powders the maximum-charge window runs from 2,129 fps to 3,422 fps. Accurate 8700 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 57–90 %, leaving at least 10 % headroom. The 140.0 gr projectile in 0.284" calls for a 1:12.0 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. ADI AR 2218, Hodgdon Retumbo, Vihtavuori N570 rank at the top here: for 7.21 Firebird with the .284 | 140gr | Peregrine VRG-3 they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon 50BMG, Hodgdon US 869, 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.