Load Specifications
Bullet Manufacturer:Peregrine
Bullet Weight:160 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:1:11.0
Load data in caliber 7.21 Firebird with .284 | 160gr | Peregrine Bushmaster (VRG-3) bullet and 108 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2218, Vihtavuori N570 and Alliant Reloder-33.
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>> | 84% | 58,320 psi | 87% | 3012 fps | 100% |
| Accurate 3100 | <<locked>> | 84% | 58,146 psi | 87% | 3009 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 55,651 psi | 83% | 3077 fps | 99% |
| Accurate 8700ᴾ | <<locked>> | 100% | 55,506 psi | 83% | 3077 fps | 98.9% |
| Accurate MAGPRO | <<locked>> | 82% | 58,044 psi | 87% | 3140 fps | 100% |
| Accurate MAGPRO | <<locked>> | 82% | 57,870 psi | 87% | 3136 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 59,408 psi | 89% | 3107 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 59,219 psi | 89% | 3107 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 58,682 psi | 88% | 3133 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 58,523 psi | 88% | 3133 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 58,566 psi | 88% | 3120 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 58,407 psi | 88% | 3117 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 59,901 psi | 90% | 3271 fps | 99.9% |
| ADI AR 2218 | <<locked>> | 96% | 59,770 psi | 90% | 3268 fps | 99.9% |
| ADI AR 2225 | <<locked>> | 94% | 58,842 psi | 88% | 3143 fps | 100% |
| ADI AR 2225 | <<locked>> | 94% | 58,682 psi | 88% | 3140 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 82% | 59,408 psi | 89% | 3100 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 58,987 psi | 88% | 3097 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 58,813 psi | 88% | 3094 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 59,117 psi | 89% | 3123 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 58,943 psi | 88% | 3120 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 57,203 psi | 86% | 3015 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 57,203 psi | 86% | 3015 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 58,508 psi | 88% | 3100 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 58,523 psi | 88% | 3100 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 57,522 psi | 86% | 3166 fps | 99.5% |
| Alliant Reloder-33 | <<locked>> | 92% | 57,377 psi | 86% | 3163 fps | 99.4% |
| Alliant Reloder-50 | <<locked>> | 96% | 57,899 psi | 87% | 3159 fps | 99.2% |
| Alliant Reloder-50 | <<locked>> | 96% | 57,566 psi | 86% | 3156 fps | 99.2% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 58,537 psi | 88% | 3094 fps | 99.6% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 58,421 psi | 88% | 3091 fps | 99.6% |
| Bofors RP15 | <<locked>> | 86% | 58,450 psi | 88% | 3114 fps | 100% |
| Bofors RP15 | <<locked>> | 86% | 58,320 psi | 87% | 3110 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 58,407 psi | 88% | 3133 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 58,233 psi | 87% | 3127 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 59,117 psi | 89% | 3123 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 58,943 psi | 88% | 3120 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 60,060 psi | 90% | 3136 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 59,886 psi | 90% | 3133 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 56,753 psi | 85% | 3058 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 56,594 psi | 85% | 3054 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 59,640 psi | 89% | 3100 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 59,814 psi | 90% | 3104 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 58,755 psi | 88% | 3205 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 58,552 psi | 88% | 3202 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,000 psi | 57% | 2001 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,101 psi | 57% | 2001 fps | 100% |
| Hodgdon US 869ᴾ | <<locked>> | 100% | 60,263 psi | 90% | 3143 fps | 96.5% |
| IMR 4955 Enduron | <<locked>> | 82% | 56,550 psi | 85% | 3031 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 60,365 psi | 90% | 3087 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 57,290 psi | 86% | 3117 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 57,101 psi | 86% | 3117 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 59,292 psi | 89% | 3054 fps | 97.6% |
| IMR 7977 Enduron | <<locked>> | 90% | 59,146 psi | 89% | 3048 fps | 97.5% |
| IMR 8133 Enduron | <<locked>> | 96% | 57,290 psi | 86% | 3127 fps | 100% |
| IMR 8133 Enduron | <<locked>> | 96% | 57,130 psi | 86% | 3123 fps | 100% |
| Lovex D100 | <<locked>> | 92% | 57,159 psi | 86% | 3045 fps | 96.3% |
| Lovex D100 | <<locked>> | 92% | 57,043 psi | 86% | 3041 fps | 96.2% |
| Lovex S071 | <<locked>> | 88% | 56,797 psi | 85% | 2992 fps | 100% |
| Lovex S071 | <<locked>> | 88% | 56,637 psi | 85% | 2986 fps | 100% |
| Norma 217 | <<locked>> | 96% | 59,132 psi | 89% | 3146 fps | 100% |
| Norma 217 | <<locked>> | 96% | 58,972 psi | 88% | 3143 fps | 100% |
| Norma MRP | <<locked>> | 82% | 59,335 psi | 89% | 3133 fps | 100% |
| Norma MRP | <<locked>> | 82% | 59,146 psi | 89% | 3130 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 58,972 psi | 88% | 3143 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 58,784 psi | 88% | 3140 fps | 100% |
| Ramshot LRT | <<locked>> | 96% | 59,117 psi | 89% | 3189 fps | 96.4% |
| Ramshot LRT | <<locked>> | 96% | 58,987 psi | 88% | 3186 fps | 96.4% |
| Ramshot Magnum | <<locked>> | 86% | 57,392 psi | 86% | 3061 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 57,217 psi | 86% | 3058 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,088 psi | 59% | 2047 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,044 psi | 59% | 2047 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 59,756 psi | 90% | 3186 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 59,582 psi | 89% | 3182 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 58,682 psi | 88% | 3163 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 58,537 psi | 88% | 3163 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 59,437 psi | 89% | 3074 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 59,263 psi | 89% | 3074 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 58,798 psi | 88% | 3087 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 58,610 psi | 88% | 3087 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 57,159 psi | 86% | 3045 fps | 96.3% |
| Shooters World 50 BMG | <<locked>> | 92% | 57,043 psi | 86% | 3041 fps | 96.2% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 57,101 psi | 86% | 3084 fps | 98.9% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 56,797 psi | 85% | 3077 fps | 98.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 58,436 psi | 88% | 3084 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 58,262 psi | 87% | 3081 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 58,929 psi | 88% | 3051 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 58,798 psi | 88% | 3048 fps | 100% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 50,328 psi | 75% | 2982 fps | 96.2% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 50,212 psi | 75% | 2979 fps | 96.1% |
| Vihtavuori N165 | <<locked>> | 86% | 59,335 psi | 89% | 3041 fps | 100% |
| Vihtavuori N165 | <<locked>> | 86% | 59,205 psi | 89% | 3041 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 58,842 psi | 88% | 3087 fps | 98.7% |
| Vihtavuori N170 | <<locked>> | 90% | 58,711 psi | 88% | 3084 fps | 98.6% |
| Vihtavuori N555 | <<locked>> | 82% | 58,697 psi | 88% | 3045 fps | 100% |
| Vihtavuori N555 | <<locked>> | 82% | 58,537 psi | 88% | 3041 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 58,537 psi | 88% | 3146 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 58,363 psi | 87% | 3143 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 60,191 psi | 90% | 3143 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 60,031 psi | 90% | 3140 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 58,697 psi | 88% | 3166 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 58,537 psi | 88% | 3163 fps | 100% |
| Vihtavuori N570 | <<locked>> | 90% | 56,362 psi | 84% | 3169 fps | 99.1% |
| Vihtavuori N570 | <<locked>> | 90% | 56,202 psi | 84% | 3169 fps | 99.1% |
| Winchester StaBALL HD | <<locked>> | 84% | 59,132 psi | 89% | 3114 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 84% | 59,176 psi | 89% | 3114 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 58,987 psi | 88% | 3051 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 58,813 psi | 88% | 3051 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% | 50,923 psi | 76% | 2900 fps | 100% |
| Accurate 3100 | <<locked>> | 80% | 50,778 psi | 76% | 2897 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 41,075 psi | 62% | 2802 fps | 95.4% |
| Accurate 8700 | <<locked>> | 92% | 40,959 psi | 61% | 2799 fps | 95.3% |
| Accurate MAGPRO | <<locked>> | 80% | 54,012 psi | 81% | 3074 fps | 99.8% |
| Accurate MAGPRO | <<locked>> | 80% | 53,838 psi | 81% | 3071 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 80% | 55,419 psi | 83% | 3048 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 55,463 psi | 83% | 3048 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 50,879 psi | 76% | 3005 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 50,734 psi | 76% | 3002 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 80% | 38,014 psi | 57% | 2740 fps | 98.4% |
| ADI AR 2217 | <<locked>> | 80% | 37,884 psi | 57% | 2736 fps | 98.3% |
| ADI AR 2218 | 94.3 gr | 86% | 40,843 psi | 61% | 2887 fps | 95.9% |
| ADI AR 2218 | 94.3 gr | 86% | 40,727 psi | 61% | 2884 fps | 95.9% |
| ADI AR 2225 | <<locked>> | 80% | 35,259 psi | 53% | 2710 fps | 99.7% |
| ADI AR 2225 | <<locked>> | 80% | 35,244 psi | 53% | 2707 fps | 99.6% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 55,521 psi | 83% | 3041 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 55,158 psi | 83% | 3038 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 54,998 psi | 82% | 3035 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 51,517 psi | 77% | 3002 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 51,343 psi | 77% | 2999 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 50,125 psi | 75% | 2910 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 49,966 psi | 75% | 2907 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 44,280 psi | 66% | 2871 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 44,266 psi | 66% | 2871 fps | 100% |
| Alliant Reloder-33 | 91.5 gr | 82% | 39,189 psi | 59% | 2802 fps | 95.1% |
| Alliant Reloder-33 | 91.5 gr | 82% | 39,044 psi | 59% | 2799 fps | 95% |
| Alliant Reloder-50 | <<locked>> | 88% | 42,569 psi | 64% | 2867 fps | 95.8% |
| Alliant Reloder-50 | <<locked>> | 88% | 42,438 psi | 64% | 2864 fps | 95.7% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 48,022 psi | 72% | 2907 fps | 98.1% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 47,877 psi | 72% | 2907 fps | 98.1% |
| Bofors RP15 | <<locked>> | 80% | 47,877 psi | 72% | 2936 fps | 100% |
| Bofors RP15 | <<locked>> | 80% | 47,732 psi | 72% | 2933 fps | 99.9% |
| Bofors RP30 | <<locked>> | 80% | 41,278 psi | 62% | 2818 fps | 99% |
| Bofors RP30 | <<locked>> | 80% | 41,104 psi | 62% | 2815 fps | 99% |
| Bofors RP5 | <<locked>> | 80% | 51,517 psi | 77% | 3002 fps | 100% |
| Bofors RP5 | <<locked>> | 80% | 51,343 psi | 77% | 2999 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 41,582 psi | 62% | 2822 fps | 99.5% |
| Hodgdon H1000 | <<locked>> | 80% | 41,423 psi | 62% | 2818 fps | 99.4% |
| Hodgdon H4831 | <<locked>> | 80% | 52,968 psi | 79% | 2995 fps | 99.8% |
| Hodgdon H4831 | <<locked>> | 80% | 52,982 psi | 79% | 2995 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 80% | 51,938 psi | 78% | 2976 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 80% | 52,112 psi | 78% | 2979 fps | 99.8% |
| Hodgdon Retumbo | <<locked>> | 80% | 43,656 psi | 65% | 2946 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 43,642 psi | 65% | 2946 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,601 psi | 43% | 1795 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,529 psi | 43% | 1791 fps | 100% |
| Hodgdon US 869 | <<locked>> | 98% | 56,028 psi | 84% | 3074 fps | 95.5% |
| IMR 4955 Enduron | <<locked>> | 80% | 53,084 psi | 80% | 2972 fps | 99.9% |
| IMR 4955 Enduron | <<locked>> | 80% | 53,084 psi | 80% | 2972 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 49,603 psi | 74% | 2989 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 80% | 49,617 psi | 74% | 2989 fps | 99.8% |
| IMR 7977 Enduron | <<locked>> | 84% | 48,718 psi | 73% | 2867 fps | 95.2% |
| IMR 7977 Enduron | <<locked>> | 84% | 48,573 psi | 73% | 2864 fps | 95.1% |
| IMR 8133 Enduron | <<locked>> | 80% | 32,721 psi | 49% | 2618 fps | 96.2% |
| IMR 8133 Enduron | <<locked>> | 80% | 32,576 psi | 49% | 2618 fps | 96.1% |
| Lovex D100 | <<locked>> | 90% | 53,171 psi | 80% | 2976 fps | 95.3% |
| Lovex D100 | <<locked>> | 90% | 53,055 psi | 80% | 2972 fps | 95.2% |
| Lovex S071 | <<locked>> | 80% | 43,772 psi | 66% | 2776 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 43,613 psi | 65% | 2772 fps | 100% |
| Norma 217 | <<locked>> | 80% | 33,272 psi | 50% | 2648 fps | 98.4% |
| Norma 217 | <<locked>> | 80% | 33,257 psi | 50% | 2648 fps | 98.4% |
| Norma MRP | <<locked>> | 80% | 55,332 psi | 83% | 3071 fps | 100% |
| Norma MRP | <<locked>> | 80% | 55,187 psi | 83% | 3071 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 50,836 psi | 76% | 3012 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 50,676 psi | 76% | 3009 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 54,911 psi | 82% | 3114 fps | 95.4% |
| Ramshot LRT | <<locked>> | 94% | 54,795 psi | 82% | 3114 fps | 95.3% |
| Ramshot Magnum | <<locked>> | 80% | 45,774 psi | 69% | 2874 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 45,614 psi | 68% | 2871 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,356 psi | 44% | 1834 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,428 psi | 44% | 1837 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 43,685 psi | 65% | 2923 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 43,511 psi | 65% | 2917 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 39,856 psi | 60% | 2808 fps | 97.5% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 39,726 psi | 60% | 2805 fps | 97.5% |
| Rottweil R 904 | <<locked>> | 80% | 55,535 psi | 83% | 3015 fps | 100% |
| Rottweil R 904 | <<locked>> | 80% | 55,564 psi | 83% | 3015 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 55,056 psi | 83% | 3031 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 54,897 psi | 82% | 3028 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 53,171 psi | 80% | 2976 fps | 95.3% |
| Shooters World 50 BMG | <<locked>> | 90% | 53,055 psi | 80% | 2972 fps | 95.2% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 42,975 psi | 64% | 2822 fps | 95.7% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 42,859 psi | 64% | 2818 fps | 95.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 54,708 psi | 82% | 3028 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 54,549 psi | 82% | 3025 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 55,114 psi | 83% | 2995 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 54,984 psi | 82% | 2992 fps | 100% |
| Vihtavuori 20N29 | <<locked>> | 98% | 46,644 psi | 70% | 2910 fps | 95.1% |
| Vihtavuori 20N29 | <<locked>> | 98% | 46,543 psi | 70% | 2910 fps | 95% |
| Vihtavuori N165 | <<locked>> | 80% | 48,515 psi | 73% | 2874 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 48,385 psi | 73% | 2871 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 44,643 psi | 67% | 2828 fps | 95.6% |
| Vihtavuori N170 | <<locked>> | 82% | 44,527 psi | 67% | 2825 fps | 95.5% |
| Vihtavuori N555 | <<locked>> | 80% | 55,013 psi | 82% | 2992 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 54,824 psi | 82% | 2989 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 54,636 psi | 82% | 3084 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 54,462 psi | 82% | 3077 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 80% | 45,556 psi | 68% | 2890 fps | 99.3% |
| Vihtavuori N565 | <<locked>> | 80% | 45,571 psi | 68% | 2890 fps | 99.3% |
| Vihtavuori N568 | <<locked>> | 80% | 40,741 psi | 61% | 2825 fps | 97.3% |
| Vihtavuori N568 | <<locked>> | 80% | 40,582 psi | 61% | 2822 fps | 97.2% |
| Vihtavuori N570 | 88 gr | 82% | 41,901 psi | 63% | 2881 fps | 95.6% |
| Vihtavuori N570 | 88 gr | 82% | 41,785 psi | 63% | 2881 fps | 95.6% |
| Winchester StaBALL HD | <<locked>> | 80% | 50,981 psi | 76% | 2995 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 50,763 psi | 76% | 2992 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 51,343 psi | 77% | 2936 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 51,169 psi | 77% | 2933 fps | 100% |
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 108 powders for 7.21 Firebird loaded with the .284 | 160gr | Peregrine Bushmaster (VRG-3). ADI AR 2218 delivers the highest muzzle velocity at 3,271 fps; across all powders the maximum-charge window runs from 2,001 fps to 3,271 fps. Accurate 8700 gives the best case fill at 100 %, and 108 of the 108 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 160.0 gr projectile in 0.284" calls for a 1:11.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, Accurate 8700, 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. ADI AR 2218, Vihtavuori N570, Alliant Reloder-33 rank at the top here: for 7.21 Firebird with the .284 | 160gr | Peregrine Bushmaster (VRG-3) 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.