Load Specifications
Load data in caliber 7.21 Firebird with .284 | 160gr | Brenneke TAG bullet and 53 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 IMR 8133 Enduron.
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% | 58,494 psi | 88% | 3015 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 55,970 psi | 84% | 3084 fps | 99% |
| Accurate MAGPRO | <<locked>> | 82% | 58,204 psi | 87% | 3143 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 59,596 psi | 89% | 3114 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 58,885 psi | 88% | 3136 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 58,958 psi | 88% | 3127 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 60,263 psi | 90% | 3278 fps | 99.9% |
| ADI AR 2225 | <<locked>> | 94% | 59,001 psi | 88% | 3143 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 59,176 psi | 89% | 3100 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 59,292 psi | 89% | 3127 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 57,392 psi | 86% | 3015 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 58,885 psi | 88% | 3107 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 57,870 psi | 87% | 3173 fps | 99.5% |
| Alliant Reloder-50 | <<locked>> | 96% | 58,247 psi | 87% | 3166 fps | 99.3% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 58,682 psi | 88% | 3097 fps | 99.6% |
| Bofors RP15 | <<locked>> | 86% | 58,668 psi | 88% | 3117 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 58,581 psi | 88% | 3133 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 59,292 psi | 89% | 3127 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 56,188 psi | 84% | 3081 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 56,927 psi | 85% | 3061 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 59,973 psi | 90% | 3107 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 59,161 psi | 89% | 3212 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,116 psi | 57% | 2005 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 56,869 psi | 85% | 3035 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 57,479 psi | 86% | 3123 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 59,422 psi | 89% | 3058 fps | 97.6% |
| IMR 8133 Enduron | <<locked>> | 96% | 57,653 psi | 86% | 3133 fps | 100% |
| Lovex D100 | <<locked>> | 92% | 57,464 psi | 86% | 3051 fps | 96.4% |
| Lovex S071 | <<locked>> | 88% | 56,985 psi | 85% | 2992 fps | 100% |
| Norma 217 | <<locked>> | 96% | 59,321 psi | 89% | 3153 fps | 100% |
| Norma MRP | <<locked>> | 82% | 59,712 psi | 90% | 3140 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 59,364 psi | 89% | 3150 fps | 100% |
| Ramshot LRT | <<locked>> | 96% | 59,437 psi | 89% | 3196 fps | 96.5% |
| Ramshot Magnum | <<locked>> | 86% | 57,551 psi | 86% | 3064 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,059 psi | 59% | 2047 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 60,162 psi | 90% | 3192 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 58,842 psi | 88% | 3166 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 59,611 psi | 89% | 3081 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 59,001 psi | 88% | 3091 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 57,464 psi | 86% | 3051 fps | 96.4% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 57,217 psi | 86% | 3084 fps | 98.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 58,639 psi | 88% | 3091 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 59,146 psi | 89% | 3054 fps | 100% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 50,618 psi | 76% | 2989 fps | 96.3% |
| Vihtavuori N165 | <<locked>> | 86% | 59,524 psi | 89% | 3045 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 59,161 psi | 89% | 3094 fps | 98.7% |
| Vihtavuori N555 | <<locked>> | 82% | 58,900 psi | 88% | 3045 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 58,900 psi | 88% | 3153 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 60,365 psi | 90% | 3146 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 59,074 psi | 89% | 3169 fps | 100% |
| Vihtavuori N570 | <<locked>> | 90% | 56,724 psi | 85% | 3179 fps | 99.2% |
| Winchester StaBALL HD | <<locked>> | 84% | 59,611 psi | 89% | 3120 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 59,132 psi | 89% | 3054 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% | 51,111 psi | 77% | 2904 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 41,350 psi | 62% | 2808 fps | 95.5% |
| Accurate MAGPRO | <<locked>> | 80% | 54,186 psi | 81% | 3077 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 80% | 55,622 psi | 83% | 3051 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 51,068 psi | 77% | 3009 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 80% | 38,189 psi | 57% | 2746 fps | 98.4% |
| ADI AR 2218 | 94.8 gr | 86% | 40,973 psi | 61% | 2890 fps | 96% |
| ADI AR 2225 | <<locked>> | 80% | 35,433 psi | 53% | 2713 fps | 99.7% |
| Alliant Reloder-19 | <<locked>> | 80% | 55,347 psi | 83% | 3041 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 51,706 psi | 78% | 3005 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 50,343 psi | 75% | 2913 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 44,469 psi | 67% | 2874 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 82% | 39,479 psi | 59% | 2808 fps | 95.2% |
| Alliant Reloder-50 | <<locked>> | 88% | 42,873 psi | 64% | 2874 fps | 95.9% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 48,153 psi | 72% | 2913 fps | 98.2% |
| Bofors RP15 | <<locked>> | 80% | 48,066 psi | 72% | 2940 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 41,452 psi | 62% | 2822 fps | 99.1% |
| Bofors RP5 | <<locked>> | 80% | 51,706 psi | 78% | 3005 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 41,771 psi | 63% | 2825 fps | 99.5% |
| Hodgdon H4831 | <<locked>> | 80% | 53,142 psi | 80% | 2999 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 52,286 psi | 78% | 2986 fps | 99.8% |
| Hodgdon Retumbo | <<locked>> | 80% | 43,874 psi | 66% | 2949 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,601 psi | 43% | 1795 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 53,243 psi | 80% | 2976 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 49,980 psi | 75% | 2995 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 84% | 48,863 psi | 73% | 2871 fps | 95.2% |
| IMR 8133 Enduron | 81 gr | 80% | 32,895 psi | 49% | 2625 fps | 96.3% |
| Lovex D100 | <<locked>> | 90% | 53,301 psi | 80% | 2979 fps | 95.4% |
| Lovex S071 | <<locked>> | 80% | 43,976 psi | 66% | 2779 fps | 100% |
| Norma 217 | <<locked>> | 80% | 33,460 psi | 50% | 2651 fps | 98.5% |
| Norma MRP | <<locked>> | 80% | 55,521 psi | 83% | 3077 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 51,068 psi | 77% | 3018 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 55,245 psi | 83% | 3123 fps | 95.5% |
| Ramshot Magnum | <<locked>> | 80% | 45,948 psi | 69% | 2877 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,356 psi | 44% | 1837 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 43,874 psi | 66% | 2923 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 40,016 psi | 60% | 2812 fps | 97.6% |
| Rottweil R 904 | <<locked>> | 80% | 55,724 psi | 84% | 3018 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 55,259 psi | 83% | 3035 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 53,301 psi | 80% | 2979 fps | 95.4% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 43,265 psi | 65% | 2828 fps | 95.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 54,911 psi | 82% | 3031 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 55,303 psi | 83% | 2995 fps | 100% |
| Vihtavuori 20N29 | <<locked>> | 98% | 46,934 psi | 70% | 2917 fps | 95.2% |
| Vihtavuori N165 | <<locked>> | 80% | 48,704 psi | 73% | 2877 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 44,933 psi | 67% | 2835 fps | 95.7% |
| Vihtavuori N555 | <<locked>> | 80% | 55,230 psi | 83% | 2995 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 54,824 psi | 82% | 3084 fps | 100% |
| Vihtavuori N565 | <<locked>> | 80% | 45,759 psi | 69% | 2897 fps | 99.3% |
| Vihtavuori N568 | <<locked>> | 80% | 40,901 psi | 61% | 2828 fps | 97.3% |
| Vihtavuori N570 | 88.6 gr | 82% | 42,235 psi | 63% | 2890 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 80% | 51,184 psi | 77% | 2999 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 51,503 psi | 77% | 2936 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 56 powders for 7.21 Firebird loaded with the .284 | 160gr | Brenneke TAG. ADI AR 2218 delivers the highest muzzle velocity at 3,278 fps; across all powders the maximum-charge window runs from 2,005 fps to 3,278 fps. Accurate 8700 gives the best case fill at 100 %, and 56 of the 56 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, IMR 8133 Enduron rank at the top here: for 7.21 Firebird with the .284 | 160gr | Brenneke TAG 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.