Load Specifications
Load data in caliber 7.21 Firebird with .284 | 160gr | Speer TBBC 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.
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% | 59,437 psi | 89% | 3022 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 56,449 psi | 85% | 3087 fps | 99% |
| Accurate MAGPRO | <<locked>> | 82% | 58,769 psi | 88% | 3146 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 60,031 psi | 90% | 3114 fps | 100% |
| ADI AR 2213 | <<locked>> | 84% | 59,219 psi | 89% | 3140 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 59,190 psi | 89% | 3127 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 56,043 psi | 84% | 3205 fps | 99.6% |
| ADI AR 2225 | <<locked>> | 94% | 59,422 psi | 89% | 3150 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 59,437 psi | 89% | 3100 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 59,712 psi | 90% | 3130 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 58,030 psi | 87% | 3022 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 59,379 psi | 89% | 3107 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 58,320 psi | 87% | 3176 fps | 99.5% |
| Alliant Reloder-50 | <<locked>> | 96% | 58,885 psi | 88% | 3176 fps | 99.3% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 58,987 psi | 88% | 3097 fps | 99.6% |
| Bofors RP15 | <<locked>> | 86% | 59,103 psi | 89% | 3120 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 59,219 psi | 89% | 3140 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 59,712 psi | 90% | 3130 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 56,434 psi | 85% | 3081 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 57,435 psi | 86% | 3064 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 60,292 psi | 90% | 3107 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 59,408 psi | 89% | 3212 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,101 psi | 57% | 1998 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 57,290 psi | 86% | 3038 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 57,812 psi | 87% | 3123 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 59,785 psi | 90% | 3054 fps | 97.6% |
| IMR 8133 Enduron | <<locked>> | 96% | 58,233 psi | 87% | 3140 fps | 100% |
| Lovex D100 | <<locked>> | 92% | 57,827 psi | 87% | 3051 fps | 96.4% |
| Lovex S071 | <<locked>> | 88% | 57,899 psi | 87% | 3002 fps | 100% |
| Norma 217 | <<locked>> | 96% | 59,959 psi | 90% | 3156 fps | 100% |
| Norma MRP | <<locked>> | 82% | 60,176 psi | 90% | 3143 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 59,611 psi | 89% | 3150 fps | 100% |
| Ramshot LRT | <<locked>> | 96% | 59,741 psi | 90% | 3196 fps | 96.5% |
| Ramshot Magnum | <<locked>> | 86% | 58,204 psi | 87% | 3071 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,218 psi | 59% | 2044 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 56,144 psi | 84% | 3130 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 59,495 psi | 89% | 3176 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 59,828 psi | 90% | 3077 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 59,524 psi | 89% | 3094 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 57,827 psi | 87% | 3051 fps | 96.4% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 57,783 psi | 87% | 3091 fps | 98.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 59,190 psi | 89% | 3091 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 59,596 psi | 89% | 3054 fps | 100% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 51,314 psi | 77% | 2999 fps | 96.4% |
| Vihtavuori N165 | <<locked>> | 86% | 59,944 psi | 90% | 3045 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 59,683 psi | 89% | 3094 fps | 98.8% |
| Vihtavuori N555 | <<locked>> | 82% | 59,640 psi | 89% | 3051 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 59,335 psi | 89% | 3156 fps | 100% |
| Vihtavuori N565 | <<locked>> | 86% | 57,087 psi | 86% | 3091 fps | 100% |
| Vihtavuori N568 | <<locked>> | 90% | 59,553 psi | 89% | 3176 fps | 100% |
| Vihtavuori N570 | <<locked>> | 90% | 57,203 psi | 86% | 3186 fps | 99.2% |
| Winchester StaBALL HD | <<locked>> | 84% | 60,191 psi | 90% | 3127 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 59,567 psi | 89% | 3058 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% | 51,967 psi | 78% | 2913 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 41,858 psi | 63% | 2818 fps | 95.7% |
| Accurate MAGPRO | <<locked>> | 80% | 54,708 psi | 82% | 3081 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 80% | 56,028 psi | 84% | 3054 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 51,561 psi | 77% | 3015 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 80% | 38,783 psi | 58% | 2756 fps | 98.6% |
| ADI AR 2218 | 93.6 gr | 86% | 41,510 psi | 62% | 2900 fps | 96.2% |
| ADI AR 2225 | <<locked>> | 80% | 36,114 psi | 54% | 2730 fps | 99.8% |
| Alliant Reloder-19 | <<locked>> | 80% | 55,796 psi | 84% | 3041 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 52,286 psi | 78% | 3012 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 50,923 psi | 76% | 2920 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 45,078 psi | 68% | 2884 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 82% | 40,074 psi | 60% | 2822 fps | 95.5% |
| Alliant Reloder-50 | <<locked>> | 86% | 40,683 psi | 61% | 2825 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 48,443 psi | 73% | 2913 fps | 98.2% |
| Bofors RP15 | <<locked>> | 80% | 48,646 psi | 73% | 2946 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 42,192 psi | 63% | 2838 fps | 99.2% |
| Bofors RP5 | <<locked>> | 80% | 52,286 psi | 78% | 3012 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 42,322 psi | 63% | 2835 fps | 99.6% |
| Hodgdon H4831 | <<locked>> | 80% | 53,621 psi | 80% | 3002 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 52,750 psi | 79% | 2986 fps | 99.8% |
| Hodgdon Retumbo | <<locked>> | 80% | 44,469 psi | 67% | 2959 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,761 psi | 43% | 1795 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 53,650 psi | 80% | 2979 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 50,314 psi | 75% | 2999 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 84% | 49,197 psi | 74% | 2874 fps | 95.2% |
| IMR 8133 Enduron | 80 gr | 80% | 33,678 psi | 50% | 2648 fps | 96.6% |
| Lovex D100 | <<locked>> | 90% | 53,824 psi | 81% | 2982 fps | 95.4% |
| Lovex S071 | <<locked>> | 80% | 44,802 psi | 67% | 2789 fps | 100% |
| Norma 217 | <<locked>> | 80% | 34,330 psi | 51% | 2674 fps | 98.8% |
| Norma MRP | <<locked>> | 80% | 56,043 psi | 84% | 3081 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 51,503 psi | 77% | 3022 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 55,521 psi | 83% | 3123 fps | 95.5% |
| Ramshot Magnum | <<locked>> | 80% | 46,543 psi | 70% | 2884 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,544 psi | 44% | 1834 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 44,483 psi | 67% | 2933 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 40,814 psi | 61% | 2828 fps | 97.8% |
| Rottweil R 904 | <<locked>> | 80% | 56,115 psi | 84% | 3022 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 55,593 psi | 83% | 3035 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 53,824 psi | 81% | 2982 fps | 95.4% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 43,932 psi | 66% | 2838 fps | 95.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 55,245 psi | 83% | 3031 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 55,956 psi | 84% | 3002 fps | 100% |
| Vihtavuori 20N29 | <<locked>> | 98% | 47,630 psi | 71% | 2930 fps | 95.3% |
| Vihtavuori N165 | <<locked>> | 80% | 49,284 psi | 74% | 2881 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 45,600 psi | 68% | 2844 fps | 95.8% |
| Vihtavuori N555 | <<locked>> | 80% | 55,956 psi | 84% | 2999 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 55,216 psi | 83% | 3091 fps | 100% |
| Vihtavuori N565 | <<locked>> | 80% | 46,572 psi | 70% | 2910 fps | 99.4% |
| Vihtavuori N568 | <<locked>> | 80% | 41,698 psi | 63% | 2844 fps | 97.6% |
| Vihtavuori N570 | 87.5 gr | 82% | 42,902 psi | 64% | 2904 fps | 96% |
| Winchester StaBALL HD | <<locked>> | 80% | 51,822 psi | 78% | 3005 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 51,909 psi | 78% | 2940 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 53 powders for 7.21 Firebird loaded with the .284 | 160gr | Speer TBBC. Hodgdon Retumbo delivers the highest muzzle velocity at 3,212 fps; across all powders the maximum-charge window runs from 1,998 fps to 3,212 fps. Accurate 8700 gives the best case fill at 100 %, and 53 of the 53 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 1:10.5 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 | Speer TBBC 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.