Load Specifications
Bullet Manufacturer:Peregrine
Bullet Weight:136 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:1:9.5
Load data in caliber 7.21 Firebird with .284 | 136gr | Peregrine VLR5 (VLR-5) bullet and 106 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.
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% | 59,538 psi | 89% | 3238 fps | 100% |
| Accurate 3100 | <<locked>> | 88% | 59,901 psi | 90% | 3241 fps | 100% |
| Accurate High Country | <<locked>> | 84% | 58,175 psi | 87% | 3356 fps | 99.9% |
| Accurate MAGPRO | <<locked>> | 86% | 59,030 psi | 88% | 3363 fps | 99.6% |
| Accurate MAGPRO | <<locked>> | 86% | 59,422 psi | 89% | 3366 fps | 99.6% |
| ADI AR 2209 | <<locked>> | 84% | 56,840 psi | 85% | 3278 fps | 100% |
| ADI AR 2209 | <<locked>> | 84% | 57,217 psi | 86% | 3284 fps | 100% |
| ADI AR 2213 | <<locked>> | 88% | 59,625 psi | 89% | 3356 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 88% | 60,191 psi | 90% | 3369 fps | 100% |
| ADI AR 2217 | <<locked>> | 96% | 58,972 psi | 88% | 3333 fps | 100% |
| ADI AR 2217 | <<locked>> | 96% | 59,524 psi | 89% | 3340 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 60,292 psi | 90% | 3474 fps | 99.2% |
| ADI AR 2218 | <<locked>> | 98% | 56,188 psi | 84% | 3399 fps | 98.6% |
| ADI AR 2225 | <<locked>> | 98% | 58,407 psi | 88% | 3353 fps | 100% |
| ADI AR 2225 | <<locked>> | 98% | 58,726 psi | 88% | 3353 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 84% | 57,261 psi | 86% | 3278 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 60,234 psi | 90% | 3327 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 56,666 psi | 85% | 3271 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 88% | 59,886 psi | 90% | 3346 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 56,434 psi | 85% | 3291 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 57,928 psi | 87% | 3241 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 58,320 psi | 87% | 3248 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 58,914 psi | 88% | 3323 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 59,306 psi | 89% | 3330 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 59,045 psi | 89% | 3337 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 59,437 psi | 89% | 3340 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 57,609 psi | 86% | 3366 fps | 98.5% |
| Alliant Reloder-33 | <<locked>> | 96% | 58,117 psi | 87% | 3369 fps | 98.6% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 57,435 psi | 86% | 3346 fps | 98% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 58,117 psi | 87% | 3356 fps | 98.2% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 60,017 psi | 90% | 3310 fps | 98.9% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 56,521 psi | 85% | 3251 fps | 98.4% |
| Bofors RP15 | <<locked>> | 90% | 59,234 psi | 89% | 3337 fps | 100% |
| Bofors RP15 | <<locked>> | 90% | 59,596 psi | 89% | 3343 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 58,566 psi | 88% | 3343 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 59,103 psi | 89% | 3350 fps | 100% |
| Bofors RP5 | <<locked>> | 88% | 59,886 psi | 90% | 3346 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 56,434 psi | 85% | 3291 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 56,333 psi | 84% | 3291 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 56,695 psi | 85% | 3294 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 58,421 psi | 88% | 3284 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 86% | 58,755 psi | 88% | 3291 fps | 99.7% |
| Hodgdon H4831 SC | <<locked>> | 86% | 57,246 psi | 86% | 3264 fps | 99.6% |
| Hodgdon H4831 SC | <<locked>> | 86% | 57,580 psi | 86% | 3271 fps | 99.6% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 56,956 psi | 85% | 3176 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 57,145 psi | 86% | 3179 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 58,421 psi | 88% | 3422 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 58,842 psi | 88% | 3428 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,739 psi | 57% | 2146 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,768 psi | 57% | 2149 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 58,813 psi | 88% | 3248 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 58,987 psi | 88% | 3251 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 59,669 psi | 89% | 3248 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 59,843 psi | 90% | 3251 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 58,291 psi | 87% | 3258 fps | 99.7% |
| IMR 4955 Enduron | <<locked>> | 86% | 58,624 psi | 88% | 3264 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 88% | 58,146 psi | 87% | 3340 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 88% | 58,508 psi | 88% | 3346 fps | 99.9% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 56,855 psi | 85% | 3327 fps | 100% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 57,421 psi | 86% | 3333 fps | 100% |
| Lovex S071 | <<locked>> | 92% | 57,392 psi | 86% | 3205 fps | 100% |
| Lovex S071 | <<locked>> | 92% | 57,754 psi | 87% | 3209 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 58,378 psi | 88% | 3350 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 58,958 psi | 88% | 3356 fps | 100% |
| Norma MRP | <<locked>> | 84% | 56,159 psi | 84% | 3301 fps | 100% |
| Norma MRP | <<locked>> | 84% | 56,521 psi | 85% | 3304 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 59,712 psi | 90% | 3363 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 60,133 psi | 90% | 3373 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 58,146 psi | 87% | 3281 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 58,711 psi | 88% | 3287 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,595 psi | 58% | 2192 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,624 psi | 58% | 2195 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 59,944 psi | 90% | 3409 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 60,321 psi | 90% | 3412 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 58,885 psi | 88% | 3373 fps | 99.7% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 59,379 psi | 89% | 3376 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 84% | 57,072 psi | 86% | 3241 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 84% | 57,435 psi | 86% | 3251 fps | 99.8% |
| Rottweil R 905 | <<locked>> | 86% | 59,988 psi | 90% | 3317 fps | 100% |
| Rottweil R 905 | <<locked>> | 86% | 60,365 psi | 90% | 3320 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 59,596 psi | 89% | 3314 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 59,973 psi | 90% | 3320 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 58,798 psi | 88% | 3232 fps | 99.7% |
| Somchem S361 | <<locked>> | 84% | 59,132 psi | 89% | 3235 fps | 99.8% |
| Somchem S365 | <<locked>> | 82% | 59,350 psi | 89% | 3238 fps | 100% |
| Somchem S365 | <<locked>> | 82% | 59,567 psi | 89% | 3241 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 60,350 psi | 90% | 3281 fps | 100% |
| Somchem S385 | <<locked>> | 84% | 56,739 psi | 85% | 3225 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 56,666 psi | 85% | 3205 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 57,014 psi | 85% | 3212 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 60,075 psi | 90% | 3294 fps | 97.6% |
| Vihtavuori N170 | <<locked>> | 92% | 56,362 psi | 84% | 3232 fps | 96.9% |
| Vihtavuori N555 | <<locked>> | 86% | 59,524 psi | 89% | 3271 fps | 100% |
| Vihtavuori N555 | <<locked>> | 86% | 59,944 psi | 90% | 3278 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 59,741 psi | 90% | 3373 fps | 99.8% |
| Vihtavuori N560 | <<locked>> | 86% | 60,118 psi | 90% | 3379 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 90% | 56,724 psi | 85% | 3294 fps | 99.7% |
| Vihtavuori N565 | <<locked>> | 90% | 57,232 psi | 86% | 3304 fps | 99.8% |
| Vihtavuori N568 | <<locked>> | 94% | 58,972 psi | 88% | 3369 fps | 99.5% |
| Vihtavuori N568 | <<locked>> | 94% | 59,495 psi | 89% | 3379 fps | 99.5% |
| Vihtavuori N570 | <<locked>> | 94% | 56,318 psi | 84% | 3369 fps | 97.9% |
| Vihtavuori N570 | <<locked>> | 94% | 56,840 psi | 85% | 3379 fps | 98% |
| Winchester StaBALL HD | <<locked>> | 88% | 59,016 psi | 88% | 3340 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 88% | 59,437 psi | 89% | 3343 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 56,391 psi | 85% | 3219 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 56,724 psi | 85% | 3219 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% | 45,107 psi | 68% | 2992 fps | 100% |
| Accurate 3100 | <<locked>> | 80% | 45,310 psi | 68% | 2995 fps | 100% |
| Accurate High Country | <<locked>> | 80% | 50,328 psi | 75% | 3215 fps | 99.2% |
| Accurate MAGPRO | <<locked>> | 80% | 47,326 psi | 71% | 3143 fps | 97.8% |
| Accurate MAGPRO | <<locked>> | 80% | 47,659 psi | 71% | 3150 fps | 97.9% |
| ADI AR 2209 | <<locked>> | 80% | 49,487 psi | 74% | 3146 fps | 99.6% |
| ADI AR 2209 | <<locked>> | 80% | 49,864 psi | 75% | 3156 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 80% | 44,831 psi | 67% | 3084 fps | 98.2% |
| ADI AR 2213 | <<locked>> | 80% | 45,034 psi | 68% | 3087 fps | 98.3% |
| ADI AR 2217 | <<locked>> | 82% | 35,549 psi | 53% | 2851 fps | 95.7% |
| ADI AR 2217 | <<locked>> | 82% | 35,839 psi | 54% | 2861 fps | 95.9% |
| ADI AR 2218 | <<locked>> | 92% | 44,164 psi | 66% | 3136 fps | 95% |
| ADI AR 2218 | <<locked>> | 92% | 44,556 psi | 67% | 3146 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 80% | 30,371 psi | 46% | 2740 fps | 96.5% |
| ADI AR 2225 | <<locked>> | 80% | 30,632 psi | 46% | 2746 fps | 96.6% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 50,053 psi | 75% | 3150 fps | 99.7% |
| Alliant Reloder-19 | <<locked>> | 80% | 49,371 psi | 74% | 3140 fps | 99.6% |
| Alliant Reloder-19 | <<locked>> | 80% | 49,588 psi | 74% | 3140 fps | 99.6% |
| Alliant Reloder-22 | <<locked>> | 80% | 45,498 psi | 68% | 3087 fps | 99.2% |
| Alliant Reloder-22 | <<locked>> | 80% | 45,687 psi | 68% | 3091 fps | 99.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 44,106 psi | 66% | 3012 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 44,353 psi | 66% | 3018 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 38,290 psi | 57% | 2946 fps | 99.8% |
| Alliant Reloder-25 | <<locked>> | 80% | 38,638 psi | 58% | 2953 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 50,647 psi | 76% | 3202 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 51,024 psi | 76% | 3209 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 45,527 psi | 68% | 3130 fps | 95.5% |
| Alliant Reloder-33 | <<locked>> | 90% | 45,977 psi | 69% | 3136 fps | 95.7% |
| Alliant Reloder-50 | <<locked>> | 96% | 49,153 psi | 74% | 3189 fps | 96.1% |
| Alliant Reloder-50 | <<locked>> | 94% | 45,948 psi | 69% | 3117 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 42,931 psi | 64% | 2982 fps | 95% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 43,178 psi | 65% | 2989 fps | 95.1% |
| Bofors RP15 | <<locked>> | 80% | 42,221 psi | 63% | 3012 fps | 98.5% |
| Bofors RP15 | <<locked>> | 80% | 42,424 psi | 64% | 3015 fps | 98.5% |
| Bofors RP30 | <<locked>> | 80% | 35,679 psi | 53% | 2864 fps | 95.8% |
| Bofors RP30 | <<locked>> | 80% | 35,868 psi | 54% | 2871 fps | 95.9% |
| Bofors RP5 | <<locked>> | 80% | 45,498 psi | 68% | 3087 fps | 99.2% |
| Bofors RP5 | <<locked>> | 80% | 45,687 psi | 68% | 3091 fps | 99.2% |
| Hodgdon H1000 | <<locked>> | 80% | 36,143 psi | 54% | 2871 fps | 96.6% |
| Hodgdon H1000 | <<locked>> | 80% | 36,332 psi | 54% | 2874 fps | 96.7% |
| Hodgdon H4831 | <<locked>> | 80% | 47,268 psi | 71% | 3084 fps | 98.2% |
| Hodgdon H4831 | <<locked>> | 80% | 47,587 psi | 71% | 3087 fps | 98.3% |
| Hodgdon H4831 SC | <<locked>> | 80% | 46,470 psi | 70% | 3068 fps | 98% |
| Hodgdon H4831 SC | <<locked>> | 80% | 46,644 psi | 70% | 3071 fps | 98.1% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 53,258 psi | 80% | 3120 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 53,461 psi | 80% | 3123 fps | 100% |
| Hodgdon Retumbo | 83 gr | 80% | 37,391 psi | 56% | 2992 fps | 98.2% |
| Hodgdon Retumbo | 83 gr | 80% | 37,710 psi | 57% | 3002 fps | 98.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,311 psi | 42% | 1926 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,253 psi | 42% | 1926 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 55,042 psi | 83% | 3189 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 55,390 psi | 83% | 3196 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 55,709 psi | 84% | 3189 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 56,101 psi | 84% | 3196 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 47,964 psi | 72% | 3068 fps | 98.5% |
| IMR 4955 Enduron | <<locked>> | 80% | 48,269 psi | 72% | 3074 fps | 98.6% |
| IMR 7828 SSC | <<locked>> | 80% | 43,468 psi | 65% | 3061 fps | 97.9% |
| IMR 7828 SSC | <<locked>> | 80% | 43,816 psi | 66% | 3068 fps | 98% |
| IMR 8133 Enduron | <<locked>> | 86% | 34,606 psi | 52% | 2848 fps | 95.1% |
| IMR 8133 Enduron | <<locked>> | 86% | 34,925 psi | 52% | 2858 fps | 95.3% |
| Lovex S071 | <<locked>> | 80% | 38,595 psi | 58% | 2854 fps | 99.4% |
| Lovex S071 | <<locked>> | 80% | 38,783 psi | 58% | 2858 fps | 99.4% |
| Norma 217 | <<locked>> | 82% | 30,110 psi | 45% | 2733 fps | 95.3% |
| Norma 217 | <<locked>> | 82% | 30,429 psi | 46% | 2743 fps | 95.5% |
| Norma MRP | <<locked>> | 80% | 48,501 psi | 73% | 3163 fps | 100% |
| Norma MRP | <<locked>> | 80% | 48,878 psi | 73% | 3169 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 43,859 psi | 66% | 3074 fps | 98.4% |
| Ramshot Grand | <<locked>> | 80% | 44,237 psi | 66% | 3084 fps | 98.5% |
| Ramshot Magnum | <<locked>> | 80% | 39,450 psi | 59% | 2930 fps | 98.7% |
| Ramshot Magnum | <<locked>> | 80% | 39,769 psi | 60% | 2936 fps | 98.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,993 psi | 43% | 1972 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,935 psi | 43% | 1972 fps | 100% |
| ReloadSwiss RS 76 | 88.8 gr | 80% | 36,927 psi | 55% | 2963 fps | 99% |
| ReloadSwiss RS 76 | 88.8 gr | 80% | 37,231 psi | 56% | 2969 fps | 99.1% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 39,711 psi | 60% | 2986 fps | 95.7% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 40,045 psi | 60% | 2992 fps | 95.9% |
| Rottweil R 904 | <<locked>> | 80% | 50,053 psi | 75% | 3117 fps | 99.2% |
| Rottweil R 904 | <<locked>> | 80% | 50,415 psi | 76% | 3127 fps | 99.2% |
| Rottweil R 905 | <<locked>> | 80% | 48,878 psi | 73% | 3127 fps | 99.6% |
| Rottweil R 905 | <<locked>> | 80% | 49,255 psi | 74% | 3130 fps | 99.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 48,544 psi | 73% | 3120 fps | 99.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 48,921 psi | 73% | 3127 fps | 99.6% |
| Somchem S361 | <<locked>> | 80% | 51,242 psi | 77% | 3104 fps | 98.9% |
| Somchem S361 | <<locked>> | 80% | 51,517 psi | 77% | 3107 fps | 99% |
| Somchem S365 | <<locked>> | 80% | 55,288 psi | 83% | 3179 fps | 100% |
| Somchem S365 | <<locked>> | 80% | 55,709 psi | 84% | 3186 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 49,342 psi | 74% | 3097 fps | 99.9% |
| Somchem S385 | <<locked>> | 80% | 49,516 psi | 74% | 3100 fps | 99.9% |
| Vihtavuori N165 | <<locked>> | 80% | 43,149 psi | 65% | 2959 fps | 99.2% |
| Vihtavuori N165 | <<locked>> | 80% | 43,323 psi | 65% | 2963 fps | 99.2% |
| Vihtavuori N170 | <<locked>> | 90% | 52,199 psi | 78% | 3153 fps | 95.8% |
| Vihtavuori N170 | <<locked>> | 88% | 49,008 psi | 73% | 3091 fps | 95% |
| Vihtavuori N555 | <<locked>> | 80% | 48,733 psi | 73% | 3100 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 48,965 psi | 73% | 3104 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 48,066 psi | 72% | 3159 fps | 98.5% |
| Vihtavuori N560 | <<locked>> | 80% | 48,428 psi | 73% | 3169 fps | 98.6% |
| Vihtavuori N565 | <<locked>> | 80% | 39,813 psi | 60% | 2949 fps | 96.5% |
| Vihtavuori N565 | <<locked>> | 80% | 40,161 psi | 60% | 2959 fps | 96.7% |
| Vihtavuori N568 | <<locked>> | 84% | 40,727 psi | 61% | 3005 fps | 95.5% |
| Vihtavuori N568 | <<locked>> | 84% | 41,046 psi | 62% | 3012 fps | 95.6% |
| Vihtavuori N570 | 96.9 gr | 90% | 48,472 psi | 73% | 3215 fps | 96% |
| Vihtavuori N570 | 96.9 gr | 90% | 48,965 psi | 73% | 3225 fps | 96.1% |
| Winchester StaBALL HD | <<locked>> | 80% | 43,076 psi | 65% | 3077 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 43,497 psi | 65% | 3084 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 45,527 psi | 68% | 3018 fps | 99.2% |
| Winchester Supreme 780 | <<locked>> | 80% | 45,847 psi | 69% | 3025 fps | 99.2% |
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 106 powders for 7.21 Firebird loaded with the .284 | 136gr | Peregrine VLR5 (VLR-5). ADI AR 2218 delivers the highest muzzle velocity at 3,474 fps; across all powders the maximum-charge window runs from 2,146 fps to 3,474 fps. ADI AR 2218 gives the best case fill at 100 %, and 106 of the 106 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 136.0 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, 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, ReloadSwiss RS 76 rank at the top here: for 7.21 Firebird with the .284 | 136gr | Peregrine VLR5 (VLR-5) 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.