Load Specifications
Load data in caliber 7.21 Firebird with .287 | 175gr | Woodleigh PP SN bullet and 43 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 Ramshot LRT.
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>> | 82% | 59,016 psi | 88% | 2900 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 56,782 psi | 85% | 2989 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 82% | 58,885 psi | 88% | 3018 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 59,451 psi | 89% | 3012 fps | 100% |
| ADI AR 2218 | <<locked>> | 92% | 56,623 psi | 85% | 3104 fps | 99.9% |
| ADI AR 2225 | <<locked>> | 92% | 59,872 psi | 90% | 3035 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 59,466 psi | 89% | 3009 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 82% | 57,972 psi | 87% | 2900 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 59,408 psi | 89% | 2989 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 58,697 psi | 88% | 3071 fps | 99.9% |
| Alliant Reloder-50 | <<locked>> | 94% | 59,437 psi | 89% | 3077 fps | 99.8% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 58,421 psi | 88% | 2982 fps | 99.9% |
| Bofors RP15 | <<locked>> | 84% | 59,045 psi | 89% | 3002 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 59,306 psi | 89% | 3025 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 59,466 psi | 89% | 3009 fps | 100% |
| Hodgdon H1000 | <<locked>> | 86% | 56,666 psi | 85% | 2969 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 59,799 psi | 90% | 2986 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 60,089 psi | 90% | 3097 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,377 psi | 58% | 1923 fps | 100% |
| Hodgdon US 869 | <<locked>> | 96% | 57,029 psi | 85% | 2989 fps | 96.7% |
| IMR 4955 Enduron | <<locked>> | 82% | 60,205 psi | 90% | 2969 fps | 100% |
| IMR 7828 SSC | <<locked>> | 82% | 57,856 psi | 87% | 3009 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 59,277 psi | 89% | 2946 fps | 98.3% |
| IMR 8133 Enduron | <<locked>> | 94% | 58,726 psi | 88% | 3031 fps | 100% |
| Lovex D100 | <<locked>> | 90% | 57,522 psi | 86% | 2946 fps | 97.2% |
| Lovex S071 | <<locked>> | 86% | 57,725 psi | 87% | 2884 fps | 100% |
| Norma 217 | <<locked>> | 92% | 56,753 psi | 85% | 2995 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 59,669 psi | 89% | 3031 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 59,901 psi | 90% | 3094 fps | 97.4% |
| Ramshot Magnum | <<locked>> | 84% | 58,015 psi | 87% | 2953 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,392 psi | 59% | 1965 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 84% | 56,579 psi | 85% | 3018 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 59,770 psi | 90% | 3064 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 57,522 psi | 86% | 2946 fps | 97.2% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 58,117 psi | 87% | 2992 fps | 99.5% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 55,680 psi | 83% | 2972 fps | 98.2% |
| Vihtavuori 24N41 | <<locked>> | 94% | 57,566 psi | 86% | 2999 fps | 96.7% |
| Vihtavuori N165 | <<locked>> | 84% | 59,509 psi | 89% | 2927 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 59,509 psi | 89% | 2989 fps | 99.3% |
| Vihtavuori N565 | <<locked>> | 84% | 57,116 psi | 86% | 2979 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 59,654 psi | 89% | 3061 fps | 100% |
| Vihtavuori N570 | <<locked>> | 88% | 57,682 psi | 86% | 3081 fps | 99.7% |
| Winchester Supreme 780 | <<locked>> | 82% | 59,059 psi | 89% | 2936 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% | 55,332 psi | 83% | 2851 fps | 100% |
| Accurate 8700 | <<locked>> | 88% | 39,465 psi | 59% | 2671 fps | 95.9% |
| ADI AR 2213 | <<locked>> | 80% | 54,911 psi | 82% | 2956 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 41,872 psi | 63% | 2720 fps | 99.7% |
| ADI AR 2218 | 87.2 gr | 80% | 36,056 psi | 54% | 2667 fps | 95% |
| ADI AR 2225 | <<locked>> | 80% | 39,276 psi | 59% | 2694 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 55,593 psi | 83% | 2949 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 54,317 psi | 81% | 2851 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 48,544 psi | 73% | 2828 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 80% | 40,524 psi | 61% | 2733 fps | 96.7% |
| Alliant Reloder-50 | <<locked>> | 82% | 38,261 psi | 57% | 2671 fps | 95.2% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 51,329 psi | 77% | 2864 fps | 99.3% |
| Bofors RP15 | <<locked>> | 80% | 51,938 psi | 78% | 2890 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 45,484 psi | 68% | 2795 fps | 99.9% |
| Bofors RP5 | <<locked>> | 80% | 55,593 psi | 83% | 2949 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 45,716 psi | 69% | 2792 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 80% | 55,840 psi | 84% | 2927 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 48,443 psi | 73% | 2917 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,877 psi | 43% | 1722 fps | 100% |
| Hodgdon US 869 | <<locked>> | 94% | 53,171 psi | 80% | 2923 fps | 95.8% |
| IMR 4955 Enduron | <<locked>> | 80% | 56,579 psi | 85% | 2913 fps | 100% |
| IMR 7828 SSC | <<locked>> | 80% | 53,925 psi | 81% | 2946 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 80% | 45,774 psi | 69% | 2710 fps | 95.4% |
| IMR 8133 Enduron | <<locked>> | 80% | 36,637 psi | 55% | 2621 fps | 98.5% |
| Lovex D100 | <<locked>> | 86% | 49,951 psi | 75% | 2818 fps | 95.5% |
| Lovex S071 | <<locked>> | 80% | 47,776 psi | 72% | 2733 fps | 100% |
| Norma 217 | <<locked>> | 80% | 37,507 psi | 56% | 2648 fps | 99.8% |
| Ramshot Grand | <<locked>> | 80% | 55,477 psi | 83% | 2969 fps | 100% |
| Ramshot LRT | 97.9 gr | 90% | 52,011 psi | 78% | 2959 fps | 95.6% |
| Ramshot Magnum | <<locked>> | 80% | 50,169 psi | 75% | 2835 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,718 psi | 45% | 1762 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 48,573 psi | 73% | 2894 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 44,396 psi | 67% | 2802 fps | 99.3% |
| Shooters World 50 BMG | <<locked>> | 86% | 49,951 psi | 75% | 2818 fps | 95.5% |
| SNPE Vectan SP 13 | <<locked>> | 86% | 38,638 psi | 58% | 2628 fps | 95.1% |
| Vihtavuori 20N29 | <<locked>> | 94% | 45,005 psi | 67% | 2779 fps | 95.6% |
| Vihtavuori 24N41 | <<locked>> | 92% | 53,548 psi | 80% | 2933 fps | 95.8% |
| Vihtavuori N165 | <<locked>> | 80% | 52,402 psi | 79% | 2825 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 45,397 psi | 68% | 2743 fps | 96.8% |
| Vihtavuori N565 | <<locked>> | 80% | 49,951 psi | 75% | 2864 fps | 100% |
| Vihtavuori N568 | <<locked>> | 80% | 45,121 psi | 68% | 2812 fps | 99% |
| Vihtavuori N570 | 85.4 gr | 80% | 43,207 psi | 65% | 2808 fps | 97.1% |
| Winchester Supreme 780 | <<locked>> | 80% | 55,158 psi | 83% | 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 44 powders for 7.21 Firebird loaded with the .287 | 175gr | Woodleigh PP SN. ADI AR 2218 delivers the highest muzzle velocity at 3,104 fps; across all powders the maximum-charge window runs from 1,923 fps to 3,104 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 44 of the 44 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (460 MPa), the top charges use 58–90 %, leaving at least 10 % headroom. The 175.0 gr projectile in 0.287" calls for a 1:11.5 twist; slower twists will usually not stabilise this weight. Hodgdon TrailBoss, ReloadSwiss RS 14, Vihtavuori 20N29 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, Ramshot LRT rank at the top here: for 7.21 Firebird with the .287 | 175gr | Woodleigh PP SN they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon 50BMG 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.