Load Specifications
Bullet Manufacturer:Peregrine
Bullet Weight:140 gr
Bullet Diameter:0.284"
Bullet Length:<<locked>>
Caliber:7.21 Firebird load data
Case Length (l3):2.8"
Cartridge Length (C.O.L.):<<locked>>
Case Capacity:121 Grains of Water
Primer Size:Large Rifle Magnum (LRM)
Barrel Length:26"
Max. allowed Pressure:66,717 psi
Recommended Twist Rate:1:9.0
Load data in caliber 7.21 Firebird with .284 | 140gr | Peregrine Plainsmaster (VLR-4) bullet and 110 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 ADI AR 2218.
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% | 60,089 psi | 90% | 3205 fps | 100% |
| Accurate 3100 | <<locked>> | 88% | 60,191 psi | 90% | 3209 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 48,022 psi | 72% | 3094 fps | 96.1% |
| Accurate 8700ᴾ | <<locked>> | 100% | 48,095 psi | 72% | 3094 fps | 96.2% |
| Accurate High Country | <<locked>> | 84% | 58,450 psi | 88% | 3327 fps | 100% |
| Accurate MAGPRO | <<locked>> | 86% | 59,698 psi | 89% | 3337 fps | 99.7% |
| Accurate MAGPRO | <<locked>> | 86% | 59,756 psi | 90% | 3337 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 84% | 57,464 psi | 86% | 3251 fps | 100% |
| ADI AR 2209 | <<locked>> | 84% | 57,566 psi | 86% | 3255 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 56,188 psi | 84% | 3264 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 86% | 56,260 psi | 84% | 3268 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 96% | 59,712 psi | 90% | 3307 fps | 100% |
| ADI AR 2217 | <<locked>> | 96% | 59,814 psi | 90% | 3307 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 56,405 psi | 85% | 3373 fps | 98.8% |
| ADI AR 2218 | <<locked>> | 98% | 56,478 psi | 85% | 3373 fps | 98.8% |
| ADI AR 2225 | <<locked>> | 98% | 59,030 psi | 88% | 3327 fps | 100% |
| ADI AR 2225 | <<locked>> | 98% | 59,132 psi | 89% | 3327 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 84% | 57,609 psi | 86% | 3248 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 56,913 psi | 85% | 3235 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 56,971 psi | 85% | 3238 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 56,594 psi | 85% | 3258 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 56,652 psi | 85% | 3258 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 58,624 psi | 88% | 3215 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 58,740 psi | 88% | 3219 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 59,611 psi | 89% | 3297 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 59,683 psi | 89% | 3297 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 59,915 psi | 90% | 3310 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 59,814 psi | 90% | 3310 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 58,334 psi | 87% | 3343 fps | 98.8% |
| Alliant Reloder-33 | <<locked>> | 96% | 58,421 psi | 88% | 3343 fps | 98.8% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 58,233 psi | 87% | 3327 fps | 98.4% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 58,305 psi | 87% | 3330 fps | 98.4% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 56,811 psi | 85% | 3225 fps | 98.6% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 56,869 psi | 85% | 3225 fps | 98.6% |
| Bofors RP15 | <<locked>> | 90% | 59,988 psi | 90% | 3310 fps | 100% |
| Bofors RP15 | <<locked>> | 90% | 59,886 psi | 90% | 3307 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 59,263 psi | 89% | 3317 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 59,364 psi | 89% | 3317 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 56,594 psi | 85% | 3258 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 56,652 psi | 85% | 3258 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 57,029 psi | 85% | 3264 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 57,130 psi | 86% | 3268 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 58,900 psi | 88% | 3258 fps | 99.8% |
| Hodgdon H4831 | <<locked>> | 86% | 59,001 psi | 88% | 3258 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 86% | 57,725 psi | 87% | 3238 fps | 99.7% |
| Hodgdon H4831 SC | <<locked>> | 86% | 57,827 psi | 87% | 3241 fps | 99.7% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 57,493 psi | 86% | 3146 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 57,595 psi | 86% | 3150 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 59,219 psi | 89% | 3396 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 59,335 psi | 89% | 3399 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,768 psi | 57% | 2116 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,724 psi | 57% | 2116 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 59,350 psi | 89% | 3219 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 59,277 psi | 89% | 3219 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 60,249 psi | 90% | 3219 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 60,162 psi | 90% | 3219 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 58,900 psi | 88% | 3232 fps | 99.8% |
| IMR 4955 Enduron | <<locked>> | 86% | 58,958 psi | 88% | 3232 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 88% | 58,726 psi | 88% | 3314 fps | 100% |
| IMR 7828 SSC | <<locked>> | 88% | 58,827 psi | 88% | 3317 fps | 100% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 57,682 psi | 86% | 3304 fps | 100% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 57,754 psi | 87% | 3304 fps | 100% |
| Lovex S071 | <<locked>> | 92% | 58,088 psi | 87% | 3179 fps | 100% |
| Lovex S071 | <<locked>> | 92% | 58,175 psi | 87% | 3182 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 59,263 psi | 89% | 3327 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 59,364 psi | 89% | 3327 fps | 100% |
| Norma MRP | <<locked>> | 84% | 56,913 psi | 85% | 3274 fps | 100% |
| Norma MRP | <<locked>> | 84% | 56,826 psi | 85% | 3271 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 56,014 psi | 84% | 3271 fps | 99.9% |
| Ramshot Grand | <<locked>> | 86% | 56,115 psi | 84% | 3274 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 58,856 psi | 88% | 3255 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 58,958 psi | 88% | 3255 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,638 psi | 58% | 2162 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,740 psi | 58% | 2165 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 55,985 psi | 84% | 3310 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 56,086 psi | 84% | 3314 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 59,567 psi | 89% | 3346 fps | 99.8% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 59,654 psi | 89% | 3350 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 84% | 57,638 psi | 86% | 3215 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 84% | 57,740 psi | 87% | 3219 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 84% | 56,739 psi | 85% | 3228 fps | 100% |
| Rottweil R 905 | <<locked>> | 84% | 56,840 psi | 85% | 3232 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 49,951 psi | 75% | 3107 fps | 96.2% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 50,024 psi | 75% | 3107 fps | 96.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 60,292 psi | 90% | 3287 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 56,463 psi | 85% | 3225 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 59,306 psi | 89% | 3202 fps | 99.8% |
| Somchem S361 | <<locked>> | 84% | 59,393 psi | 89% | 3205 fps | 99.8% |
| Somchem S365 | <<locked>> | 82% | 60,017 psi | 90% | 3209 fps | 100% |
| Somchem S365 | <<locked>> | 82% | 59,886 psi | 90% | 3205 fps | 100% |
| Somchem S385 | <<locked>> | 84% | 57,029 psi | 85% | 3192 fps | 100% |
| Somchem S385 | <<locked>> | 84% | 57,130 psi | 86% | 3196 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 57,174 psi | 86% | 3179 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 57,276 psi | 86% | 3179 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 56,739 psi | 85% | 3205 fps | 97.2% |
| Vihtavuori N170 | <<locked>> | 92% | 56,637 psi | 85% | 3202 fps | 97.1% |
| Vihtavuori N555 | <<locked>> | 86% | 60,220 psi | 90% | 3245 fps | 100% |
| Vihtavuori N555 | <<locked>> | 86% | 60,321 psi | 90% | 3248 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 60,350 psi | 90% | 3346 fps | 99.9% |
| Vihtavuori N560 | <<locked>> | 84% | 56,173 psi | 84% | 3278 fps | 99.7% |
| Vihtavuori N565 | <<locked>> | 90% | 57,363 psi | 86% | 3271 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 90% | 57,450 psi | 86% | 3271 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 94% | 59,785 psi | 90% | 3350 fps | 99.7% |
| Vihtavuori N568 | <<locked>> | 94% | 59,886 psi | 90% | 3353 fps | 99.7% |
| Vihtavuori N570 | <<locked>> | 94% | 57,116 psi | 86% | 3350 fps | 98.2% |
| Vihtavuori N570 | <<locked>> | 94% | 57,217 psi | 86% | 3353 fps | 98.3% |
| Winchester StaBALL HD | <<locked>> | 88% | 59,799 psi | 90% | 3310 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 88% | 59,901 psi | 90% | 3314 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 57,072 psi | 86% | 3192 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 57,174 psi | 86% | 3192 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% | 45,614 psi | 68% | 2972 fps | 100% |
| Accurate 3100 | <<locked>> | 80% | 45,701 psi | 69% | 2972 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 44,483 psi | 67% | 3018 fps | 95% |
| Accurate 8700 | <<locked>> | 98% | 44,556 psi | 67% | 3018 fps | 95% |
| Accurate High Country | <<locked>> | 80% | 50,691 psi | 76% | 3189 fps | 99.4% |
| Accurate MAGPRO | <<locked>> | 80% | 47,950 psi | 72% | 3120 fps | 98.1% |
| Accurate MAGPRO | <<locked>> | 80% | 48,037 psi | 72% | 3123 fps | 98.2% |
| ADI AR 2209 | <<locked>> | 80% | 49,995 psi | 75% | 3120 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 80% | 50,082 psi | 75% | 3123 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 80% | 45,368 psi | 68% | 3061 fps | 98.5% |
| ADI AR 2213 | <<locked>> | 80% | 45,281 psi | 68% | 3061 fps | 98.5% |
| ADI AR 2217 | <<locked>> | 80% | 33,504 psi | 50% | 2766 fps | 95% |
| ADI AR 2217 | <<locked>> | 80% | 33,576 psi | 50% | 2769 fps | 95.1% |
| ADI AR 2218 | 99.8 gr | 92% | 44,759 psi | 67% | 3123 fps | 95.6% |
| ADI AR 2218 | 99.8 gr | 92% | 44,846 psi | 67% | 3123 fps | 95.6% |
| ADI AR 2225 | <<locked>> | 80% | 30,763 psi | 46% | 2723 fps | 97% |
| ADI AR 2225 | <<locked>> | 80% | 30,821 psi | 46% | 2726 fps | 97% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 50,473 psi | 76% | 3123 fps | 99.8% |
| Alliant Reloder-19 | <<locked>> | 80% | 49,893 psi | 75% | 3114 fps | 99.7% |
| Alliant Reloder-19 | <<locked>> | 80% | 49,966 psi | 75% | 3114 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 46,021 psi | 69% | 3061 fps | 99.4% |
| Alliant Reloder-22 | <<locked>> | 80% | 45,948 psi | 69% | 3061 fps | 99.4% |
| Alliant Reloder-23 | <<locked>> | 80% | 44,628 psi | 67% | 2989 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 44,701 psi | 67% | 2989 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 38,798 psi | 58% | 2923 fps | 99.9% |
| Alliant Reloder-25 | <<locked>> | 80% | 38,885 psi | 58% | 2927 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 51,372 psi | 77% | 3179 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 51,474 psi | 77% | 3179 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 46,209 psi | 69% | 3110 fps | 96% |
| Alliant Reloder-33 | <<locked>> | 90% | 46,296 psi | 69% | 3114 fps | 96.1% |
| Alliant Reloder-50 | <<locked>> | 94% | 46,108 psi | 69% | 3094 fps | 95.4% |
| Alliant Reloder-50 | <<locked>> | 94% | 46,180 psi | 69% | 3097 fps | 95.5% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 43,381 psi | 65% | 2963 fps | 95.5% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 43,453 psi | 65% | 2963 fps | 95.5% |
| Bofors RP15 | <<locked>> | 80% | 42,685 psi | 64% | 2992 fps | 98.7% |
| Bofors RP15 | <<locked>> | 80% | 42,786 psi | 64% | 2992 fps | 98.8% |
| Bofors RP30 | <<locked>> | 80% | 36,143 psi | 54% | 2848 fps | 96.3% |
| Bofors RP30 | <<locked>> | 80% | 36,230 psi | 54% | 2848 fps | 96.3% |
| Bofors RP5 | <<locked>> | 80% | 46,021 psi | 69% | 3061 fps | 99.4% |
| Bofors RP5 | <<locked>> | 80% | 45,948 psi | 69% | 3061 fps | 99.4% |
| Hodgdon H1000 | <<locked>> | 80% | 36,593 psi | 55% | 2851 fps | 97.1% |
| Hodgdon H1000 | <<locked>> | 80% | 36,680 psi | 55% | 2858 fps | 97.1% |
| Hodgdon H4831 | <<locked>> | 80% | 47,776 psi | 72% | 3061 fps | 98.5% |
| Hodgdon H4831 | <<locked>> | 80% | 47,877 psi | 72% | 3061 fps | 98.5% |
| Hodgdon H4831 SC | <<locked>> | 80% | 46,963 psi | 70% | 3045 fps | 98.3% |
| Hodgdon H4831 SC | <<locked>> | 80% | 46,891 psi | 70% | 3041 fps | 98.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 53,737 psi | 81% | 3091 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 53,838 psi | 81% | 3091 fps | 100% |
| Hodgdon Retumbo | 81.9 gr | 80% | 37,898 psi | 57% | 2976 fps | 98.6% |
| Hodgdon Retumbo | 81.9 gr | 80% | 37,985 psi | 57% | 2976 fps | 98.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,268 psi | 42% | 1896 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,224 psi | 42% | 1896 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 55,506 psi | 83% | 3159 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 55,579 psi | 83% | 3163 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 56,260 psi | 84% | 3159 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 56,333 psi | 84% | 3159 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 48,399 psi | 73% | 3045 fps | 98.7% |
| IMR 4955 Enduron | <<locked>> | 80% | 48,472 psi | 73% | 3045 fps | 98.7% |
| IMR 7828 SSC | <<locked>> | 80% | 43,990 psi | 66% | 3041 fps | 98.3% |
| IMR 7828 SSC | <<locked>> | 80% | 44,092 psi | 66% | 3041 fps | 98.3% |
| IMR 8133 Enduron | <<locked>> | 86% | 35,157 psi | 53% | 2835 fps | 95.7% |
| IMR 8133 Enduron | <<locked>> | 86% | 35,230 psi | 53% | 2835 fps | 95.7% |
| Lovex S071 | <<locked>> | 80% | 39,117 psi | 59% | 2835 fps | 99.6% |
| Lovex S071 | <<locked>> | 80% | 39,073 psi | 59% | 2835 fps | 99.6% |
| Norma 217 | <<locked>> | 82% | 30,589 psi | 46% | 2720 fps | 95.9% |
| Norma 217 | <<locked>> | 82% | 30,676 psi | 46% | 2723 fps | 95.9% |
| Norma MRP | <<locked>> | 80% | 49,124 psi | 74% | 3140 fps | 100% |
| Norma MRP | <<locked>> | 80% | 49,197 psi | 74% | 3143 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 44,498 psi | 67% | 3054 fps | 98.7% |
| Ramshot Grand | <<locked>> | 80% | 44,585 psi | 67% | 3054 fps | 98.7% |
| Ramshot Magnum | <<locked>> | 80% | 40,016 psi | 60% | 2910 fps | 99% |
| Ramshot Magnum | <<locked>> | 80% | 40,118 psi | 60% | 2917 fps | 99% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,095 psi | 44% | 1946 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,066 psi | 44% | 1946 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 37,521 psi | 56% | 2946 fps | 99.3% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 37,579 psi | 56% | 2949 fps | 99.3% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 40,292 psi | 60% | 2969 fps | 96.3% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 37,260 psi | 56% | 2894 fps | 95% |
| Rottweil R 904 | <<locked>> | 80% | 50,502 psi | 76% | 3091 fps | 99.3% |
| Rottweil R 904 | <<locked>> | 80% | 50,604 psi | 76% | 3094 fps | 99.4% |
| Rottweil R 905 | <<locked>> | 80% | 49,559 psi | 74% | 3104 fps | 99.8% |
| Rottweil R 905 | <<locked>> | 80% | 49,487 psi | 74% | 3100 fps | 99.8% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 46,630 psi | 70% | 3041 fps | 95.2% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 46,702 psi | 70% | 3041 fps | 95.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 49,211 psi | 74% | 3097 fps | 99.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 49,139 psi | 74% | 3097 fps | 99.7% |
| Somchem S361 | <<locked>> | 80% | 51,764 psi | 78% | 3077 fps | 99.1% |
| Somchem S361 | <<locked>> | 80% | 51,851 psi | 78% | 3081 fps | 99.2% |
| Somchem S365 | <<locked>> | 80% | 55,898 psi | 84% | 3150 fps | 100% |
| Somchem S365 | <<locked>> | 80% | 55,970 psi | 84% | 3153 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 49,850 psi | 75% | 3071 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 49,777 psi | 75% | 3071 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 43,613 psi | 65% | 2936 fps | 99.4% |
| Vihtavuori N165 | <<locked>> | 80% | 43,700 psi | 66% | 2940 fps | 99.4% |
| Vihtavuori N170 | <<locked>> | 88% | 49,255 psi | 74% | 3068 fps | 95.3% |
| Vihtavuori N170 | <<locked>> | 88% | 49,342 psi | 74% | 3068 fps | 95.3% |
| Vihtavuori N555 | <<locked>> | 80% | 49,269 psi | 74% | 3074 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 49,342 psi | 74% | 3074 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 48,675 psi | 73% | 3140 fps | 98.8% |
| Vihtavuori N560 | <<locked>> | 80% | 48,733 psi | 73% | 3140 fps | 98.8% |
| Vihtavuori N565 | <<locked>> | 80% | 40,335 psi | 60% | 2930 fps | 97% |
| Vihtavuori N565 | <<locked>> | 80% | 40,437 psi | 61% | 2933 fps | 97% |
| Vihtavuori N568 | <<locked>> | 84% | 41,234 psi | 62% | 2986 fps | 95.9% |
| Vihtavuori N568 | <<locked>> | 84% | 41,321 psi | 62% | 2992 fps | 96% |
| Vihtavuori N570 | 93.5 gr | 88% | 45,600 psi | 68% | 3123 fps | 95.3% |
| Vihtavuori N570 | 93.5 gr | 88% | 45,701 psi | 69% | 3123 fps | 95.3% |
| Winchester StaBALL HD | <<locked>> | 80% | 43,772 psi | 66% | 3051 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 43,874 psi | 66% | 3054 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 46,035 psi | 69% | 2995 fps | 99.4% |
| Winchester Supreme 780 | <<locked>> | 80% | 46,122 psi | 69% | 2999 fps | 99.4% |
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 110 powders for 7.21 Firebird loaded with the .284 | 140gr | Peregrine Plainsmaster (VLR-4). Hodgdon Retumbo delivers the highest muzzle velocity at 3,399 fps; across all powders the maximum-charge window runs from 2,116 fps to 3,399 fps. Accurate 8700 gives the best case fill at 100 %, and 110 of the 110 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 1:9.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, Accurate 8700, 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, ADI AR 2218 rank at the top here: for 7.21 Firebird with the .284 | 140gr | Peregrine Plainsmaster (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.