Load Specifications
Load data in caliber 7.21 Firebird with .284 | 165gr | Peregrine VLR-5 bullet and 55 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>> | 84% | 57,493 psi | 86% | 2959 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 54,201 psi | 81% | 3022 fps | 98.8% |
| Accurate MAGPRO | <<locked>> | 82% | 56,927 psi | 85% | 3084 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 58,465 psi | 88% | 3054 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 57,667 psi | 86% | 3081 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 57,406 psi | 86% | 3064 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 58,436 psi | 88% | 3212 fps | 99.8% |
| ADI AR 2225 | <<locked>> | 94% | 57,363 psi | 86% | 3087 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 58,073 psi | 87% | 3045 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 58,102 psi | 87% | 3071 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 60,162 psi | 90% | 3015 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 57,566 psi | 86% | 3051 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 56,217 psi | 84% | 3110 fps | 99.4% |
| Alliant Reloder-50 | <<locked>> | 96% | 56,362 psi | 84% | 3104 fps | 99.1% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 57,624 psi | 86% | 3041 fps | 99.6% |
| Bofors RP15 | <<locked>> | 86% | 57,493 psi | 86% | 3061 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 57,203 psi | 86% | 3077 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 58,102 psi | 87% | 3071 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 58,871 psi | 88% | 3081 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 59,857 psi | 90% | 3064 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 58,842 psi | 88% | 3051 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 57,537 psi | 86% | 3150 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,000 psi | 57% | 1962 fps | 100% |
| Hodgdon US 869ᴾ | <<locked>> | 100% | 59,161 psi | 89% | 3091 fps | 96.4% |
| IMR 4955 Enduron | <<locked>> | 84% | 59,596 psi | 89% | 3035 fps | 100% |
| IMR 7828 SSC | <<locked>> | 86% | 60,292 psi | 90% | 3127 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 58,494 psi | 88% | 2999 fps | 97.5% |
| IMR 8133 Enduron | <<locked>> | 98% | 60,133 psi | 90% | 3133 fps | 100% |
| Lovex D100 | <<locked>> | 94% | 60,176 psi | 90% | 3054 fps | 97% |
| Lovex S071 | <<locked>> | 90% | 59,669 psi | 89% | 2992 fps | 100% |
| Norma 217 | <<locked>> | 96% | 57,899 psi | 87% | 3094 fps | 100% |
| Norma MRP | <<locked>> | 82% | 58,305 psi | 87% | 3081 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 57,972 psi | 87% | 3087 fps | 100% |
| Ramshot LRT | <<locked>> | 96% | 57,827 psi | 87% | 3133 fps | 96.3% |
| Ramshot Magnum | <<locked>> | 86% | 56,231 psi | 84% | 3009 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,117 psi | 59% | 2008 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 58,436 psi | 88% | 3130 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 57,232 psi | 86% | 3107 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 58,479 psi | 88% | 3022 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 58,030 psi | 87% | 3038 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 94% | 60,176 psi | 90% | 3054 fps | 97% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 55,883 psi | 84% | 3031 fps | 98.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 57,667 psi | 86% | 3031 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 59,988 psi | 90% | 3012 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 58,088 psi | 87% | 2999 fps | 100% |
| Vihtavuori 24N41 | <<locked>> | 98% | 59,959 psi | 90% | 3107 fps | 96.5% |
| Vihtavuori N165 | <<locked>> | 86% | 58,450 psi | 88% | 2992 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 57,812 psi | 87% | 3031 fps | 98.6% |
| Vihtavuori N555 | <<locked>> | 82% | 57,827 psi | 87% | 2992 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 57,551 psi | 86% | 3094 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 59,030 psi | 88% | 3091 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 57,508 psi | 86% | 3110 fps | 99.9% |
| Vihtavuori N570 | <<locked>> | 92% | 59,306 psi | 89% | 3186 fps | 99.5% |
| Winchester StaBALL HD | <<locked>> | 84% | 58,015 psi | 87% | 3061 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 58,102 psi | 87% | 3002 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% | 50,111 psi | 75% | 2851 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 40,030 psi | 60% | 2753 fps | 95.2% |
| Accurate MAGPRO | <<locked>> | 80% | 53,026 psi | 79% | 3018 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 80% | 54,752 psi | 82% | 2999 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 50,111 psi | 75% | 2956 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 80% | 37,275 psi | 56% | 2694 fps | 98.3% |
| ADI AR 2218 | 91.1 gr | 86% | 39,842 psi | 60% | 2835 fps | 95.8% |
| ADI AR 2225 | <<locked>> | 80% | 34,548 psi | 52% | 2664 fps | 99.6% |
| Alliant Reloder-19 | <<locked>> | 80% | 54,360 psi | 81% | 2986 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 50,720 psi | 76% | 2953 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 49,371 psi | 74% | 2861 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 43,584 psi | 65% | 2825 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 82% | 38,319 psi | 57% | 2753 fps | 95% |
| Alliant Reloder-50 | <<locked>> | 88% | 41,582 psi | 62% | 2818 fps | 95.7% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 47,253 psi | 71% | 2858 fps | 98.1% |
| Bofors RP15 | <<locked>> | 80% | 47,065 psi | 71% | 2884 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 40,495 psi | 61% | 2772 fps | 99% |
| Bofors RP5 | <<locked>> | 80% | 50,720 psi | 76% | 2953 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 40,828 psi | 61% | 2772 fps | 99.5% |
| Hodgdon H4831 | <<locked>> | 80% | 52,272 psi | 78% | 2946 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 80% | 51,372 psi | 77% | 2930 fps | 99.8% |
| Hodgdon Retumbo | 80 gr | 80% | 42,786 psi | 64% | 2897 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,543 psi | 43% | 1755 fps | 100% |
| Hodgdon US 869 | <<locked>> | 98% | 55,042 psi | 83% | 3025 fps | 95.4% |
| IMR 4955 Enduron | <<locked>> | 80% | 52,504 psi | 79% | 2927 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 48,776 psi | 73% | 2936 fps | 99.8% |
| IMR 7977 Enduron | <<locked>> | 84% | 48,051 psi | 72% | 2818 fps | 95.1% |
| IMR 8133 Enduron | <<locked>> | 80% | 32,082 psi | 48% | 2579 fps | 96.2% |
| Lovex D100 | <<locked>> | 90% | 52,170 psi | 78% | 2923 fps | 95.2% |
| Lovex S071 | <<locked>> | 80% | 43,163 psi | 65% | 2730 fps | 100% |
| Norma 217 | <<locked>> | 80% | 32,605 psi | 49% | 2605 fps | 98.4% |
| Norma MRP | <<locked>> | 80% | 54,447 psi | 82% | 3022 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 49,908 psi | 75% | 2959 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 53,737 psi | 81% | 3061 fps | 95.2% |
| Ramshot Magnum | <<locked>> | 80% | 44,817 psi | 67% | 2822 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,327 psi | 44% | 1798 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 42,685 psi | 64% | 2871 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 38,899 psi | 58% | 2759 fps | 97.4% |
| Rottweil R 904 | <<locked>> | 80% | 54,911 psi | 82% | 2966 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 54,215 psi | 81% | 2979 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 52,170 psi | 78% | 2923 fps | 95.2% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 42,047 psi | 63% | 2772 fps | 95.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 53,867 psi | 81% | 2976 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 56,101 psi | 84% | 2956 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 54,389 psi | 82% | 2946 fps | 100% |
| Vihtavuori 24N41 | <<locked>> | 96% | 55,709 psi | 84% | 3038 fps | 95.5% |
| Vihtavuori N165 | <<locked>> | 80% | 47,805 psi | 72% | 2825 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 43,903 psi | 66% | 2782 fps | 95.5% |
| Vihtavuori N555 | <<locked>> | 80% | 54,085 psi | 81% | 2936 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 53,766 psi | 81% | 3028 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 80% | 44,875 psi | 67% | 2844 fps | 99.3% |
| Vihtavuori N568 | <<locked>> | 80% | 39,958 psi | 60% | 2776 fps | 97.2% |
| Vihtavuori N570 | 85.1 gr | 82% | 41,046 psi | 62% | 2835 fps | 95.6% |
| Winchester StaBALL HD | <<locked>> | 80% | 49,893 psi | 75% | 2943 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 50,473 psi | 76% | 2881 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 55 powders for 7.21 Firebird loaded with the .284 | 165gr | Peregrine VLR-5. ADI AR 2218 delivers the highest muzzle velocity at 3,212 fps; across all powders the maximum-charge window runs from 1,962 fps to 3,212 fps. Accurate 8700 gives the best case fill at 100 %, and 55 of the 55 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 165.0 gr projectile in 0.284" calls for a 1:8.5 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 | 165gr | Peregrine 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.