Load Specifications
Load data in caliber 7.21 Firebird with .284 | 160gr | Nosler CT FailSafe bullet and 50 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-50.
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% | 59,814 psi | 90% | 3028 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 56,927 psi | 85% | 3097 fps | 99.1% |
| Accurate MAGPRO | <<locked>> | 82% | 59,146 psi | 89% | 3153 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 59,596 psi | 89% | 3146 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 59,799 psi | 90% | 3133 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 56,724 psi | 85% | 3215 fps | 99.7% |
| ADI AR 2225 | <<locked>> | 94% | 60,017 psi | 90% | 3156 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 59,828 psi | 90% | 3107 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 60,118 psi | 90% | 3136 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 58,450 psi | 88% | 3028 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 59,799 psi | 90% | 3117 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 58,856 psi | 88% | 3186 fps | 99.6% |
| Alliant Reloder-50 | <<locked>> | 96% | 59,582 psi | 89% | 3186 fps | 99.4% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 59,277 psi | 89% | 3104 fps | 99.7% |
| Bofors RP15 | <<locked>> | 86% | 59,683 psi | 89% | 3130 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 59,785 psi | 90% | 3150 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 60,118 psi | 90% | 3136 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 57,014 psi | 85% | 3087 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 57,798 psi | 87% | 3071 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 56,710 psi | 85% | 3054 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 60,075 psi | 90% | 3222 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,189 psi | 57% | 2001 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 57,638 psi | 86% | 3045 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 58,421 psi | 88% | 3130 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 60,075 psi | 90% | 3061 fps | 97.7% |
| IMR 8133 Enduron | <<locked>> | 96% | 58,755 psi | 88% | 3146 fps | 100% |
| Lovex D100 | <<locked>> | 92% | 58,233 psi | 87% | 3058 fps | 96.5% |
| Lovex S071 | <<locked>> | 88% | 58,305 psi | 87% | 3005 fps | 100% |
| Norma 217 | <<locked>> | 94% | 56,608 psi | 85% | 3107 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 60,263 psi | 90% | 3159 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 58,566 psi | 88% | 3074 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,320 psi | 59% | 2051 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 56,768 psi | 85% | 3140 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 60,060 psi | 90% | 3182 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 60,220 psi | 90% | 3084 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 59,930 psi | 90% | 3100 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 58,233 psi | 87% | 3058 fps | 96.5% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 58,407 psi | 88% | 3100 fps | 99% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 59,611 psi | 89% | 3097 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 59,973 psi | 90% | 3061 fps | 100% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 51,750 psi | 78% | 3005 fps | 96.5% |
| Vihtavuori N165 | <<locked>> | 86% | 60,307 psi | 90% | 3051 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 60,176 psi | 90% | 3104 fps | 98.8% |
| Vihtavuori N555 | <<locked>> | 82% | 60,089 psi | 90% | 3058 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 59,727 psi | 90% | 3163 fps | 100% |
| Vihtavuori N565 | <<locked>> | 86% | 57,479 psi | 86% | 3100 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 60,118 psi | 90% | 3186 fps | 100% |
| Vihtavuori N570 | <<locked>> | 90% | 57,783 psi | 87% | 3192 fps | 99.3% |
| Winchester StaBALL HD | <<locked>> | 82% | 56,521 psi | 85% | 3071 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 60,147 psi | 90% | 3064 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% | 52,373 psi | 79% | 2917 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 42,293 psi | 63% | 2825 fps | 95.9% |
| Accurate MAGPRO | <<locked>> | 80% | 55,274 psi | 83% | 3091 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 51,982 psi | 78% | 3022 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 80% | 39,131 psi | 59% | 2762 fps | 98.7% |
| ADI AR 2218 | 92.1 gr | 84% | 38,943 psi | 58% | 2838 fps | 95.1% |
| ADI AR 2225 | <<locked>> | 80% | 36,477 psi | 55% | 2736 fps | 99.8% |
| Alliant Reloder-19 | <<locked>> | 80% | 56,173 psi | 84% | 3051 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 52,692 psi | 79% | 3018 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 51,329 psi | 77% | 2927 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 45,484 psi | 68% | 2890 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 82% | 40,567 psi | 61% | 2831 fps | 95.7% |
| Alliant Reloder-50 | 95.8 gr | 86% | 41,176 psi | 62% | 2835 fps | 95.3% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 48,718 psi | 73% | 2920 fps | 98.3% |
| Bofors RP15 | <<locked>> | 80% | 49,066 psi | 74% | 2953 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 42,583 psi | 64% | 2841 fps | 99.2% |
| Bofors RP5 | <<locked>> | 80% | 52,692 psi | 79% | 3018 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 42,714 psi | 64% | 2841 fps | 99.6% |
| Hodgdon H4831 | <<locked>> | 80% | 53,998 psi | 81% | 3009 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 53,142 psi | 80% | 2995 fps | 99.9% |
| Hodgdon Retumbo | <<locked>> | 80% | 44,904 psi | 67% | 2969 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,776 psi | 43% | 1795 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 54,012 psi | 81% | 2986 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 50,749 psi | 76% | 3005 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 84% | 49,487 psi | 74% | 2877 fps | 95.4% |
| IMR 8133 Enduron | <<locked>> | 80% | 34,040 psi | 51% | 2654 fps | 96.8% |
| Lovex D100 | <<locked>> | 90% | 54,273 psi | 81% | 2992 fps | 95.6% |
| Lovex S071 | <<locked>> | 80% | 45,208 psi | 68% | 2795 fps | 100% |
| Norma 217 | <<locked>> | 80% | 34,693 psi | 52% | 2684 fps | 98.9% |
| Ramshot Grand | <<locked>> | 80% | 51,938 psi | 78% | 3025 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 46,920 psi | 70% | 2890 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,559 psi | 44% | 1837 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 44,889 psi | 67% | 2940 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 41,162 psi | 62% | 2835 fps | 97.9% |
| Rottweil R 904 | <<locked>> | 80% | 56,521 psi | 85% | 3028 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 56,028 psi | 84% | 3041 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 54,273 psi | 81% | 2992 fps | 95.6% |
| SNPE Vectan SP 13 | <<locked>> | 90% | 41,423 psi | 62% | 2782 fps | 95.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 55,680 psi | 83% | 3038 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 56,347 psi | 84% | 3009 fps | 100% |
| Vihtavuori 20N29 | <<locked>> | 98% | 48,225 psi | 72% | 2940 fps | 95.6% |
| Vihtavuori N165 | <<locked>> | 80% | 49,661 psi | 74% | 2887 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 42,815 psi | 64% | 2785 fps | 95% |
| Vihtavuori N555 | <<locked>> | 80% | 56,217 psi | 84% | 3002 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 55,651 psi | 83% | 3094 fps | 100% |
| Vihtavuori N565 | <<locked>> | 80% | 46,949 psi | 70% | 2913 fps | 99.5% |
| Vihtavuori N568 | <<locked>> | 80% | 42,047 psi | 63% | 2851 fps | 97.7% |
| Vihtavuori N570 | 85.9 gr | 80% | 40,147 psi | 60% | 2838 fps | 95% |
| Winchester StaBALL HD | <<locked>> | 80% | 52,301 psi | 78% | 3012 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 52,286 psi | 78% | 2946 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 54 powders for 7.21 Firebird loaded with the .284 | 160gr | Nosler CT FailSafe. Hodgdon Retumbo delivers the highest muzzle velocity at 3,222 fps; across all powders the maximum-charge window runs from 2,001 fps to 3,222 fps. Accurate 8700 gives the best case fill at 100 %, and 54 of the 54 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, Hodgdon TrailBoss, ReloadSwiss RS 14 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-50 rank at the top here: for 7.21 Firebird with the .284 | 160gr | Nosler CT FailSafe 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.