Load Specifications
Load data in caliber 7.21 Firebird with .284 | 160gr | CutEdge LZR MAX bullet and 53 powders. The key underlying parameters are shown in the table above.
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>> | 86% | 59,901 psi | 90% | 3035 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 52,605 psi | 79% | 3031 fps | 98.4% |
| Accurate MAGPRO | <<locked>> | 84% | 59,582 psi | 89% | 3166 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 57,145 psi | 86% | 3074 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 60,321 psi | 90% | 3163 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 60,060 psi | 90% | 3143 fps | 100% |
| ADI AR 2218 | <<locked>> | 96% | 56,710 psi | 85% | 3222 fps | 99.6% |
| ADI AR 2225 | <<locked>> | 96% | 59,799 psi | 90% | 3159 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 56,811 psi | 85% | 3064 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 56,710 psi | 85% | 3087 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 58,740 psi | 88% | 3038 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 59,843 psi | 90% | 3123 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 59,959 psi | 90% | 3133 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 58,798 psi | 88% | 3192 fps | 99.5% |
| Alliant Reloder-50 | <<locked>> | 98% | 58,871 psi | 88% | 3186 fps | 99.3% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 60,263 psi | 90% | 3117 fps | 99.7% |
| Bofors RP15 | <<locked>> | 88% | 60,002 psi | 90% | 3140 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 59,669 psi | 89% | 3153 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 56,710 psi | 85% | 3087 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 57,305 psi | 86% | 3100 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 58,537 psi | 88% | 3084 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 57,551 psi | 86% | 3071 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 59,988 psi | 90% | 3228 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,913 psi | 57% | 1985 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 58,421 psi | 88% | 3058 fps | 100% |
| IMR 7828 SSC | <<locked>> | 86% | 58,798 psi | 88% | 3143 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 57,101 psi | 86% | 3012 fps | 96.9% |
| IMR 8133 Enduron | <<locked>> | 98% | 58,276 psi | 87% | 3146 fps | 100% |
| Lovex D100 | <<locked>> | 94% | 58,755 psi | 88% | 3068 fps | 96.3% |
| Lovex S071 | <<locked>> | 90% | 58,262 psi | 87% | 3012 fps | 100% |
| Norma 217 | <<locked>> | 98% | 60,075 psi | 90% | 3169 fps | 100% |
| Norma MRP | <<locked>> | 82% | 56,811 psi | 85% | 3100 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 56,347 psi | 84% | 3107 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 59,001 psi | 88% | 3087 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,015 psi | 58% | 2034 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 56,623 psi | 85% | 3150 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 59,857 psi | 90% | 3189 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 57,276 psi | 86% | 3041 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 56,710 psi | 85% | 3058 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 94% | 58,755 psi | 88% | 3068 fps | 96.3% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 54,143 psi | 81% | 3038 fps | 98.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 60,104 psi | 90% | 3110 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 58,769 psi | 88% | 3035 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 56,811 psi | 85% | 3022 fps | 100% |
| Vihtavuori N165 | <<locked>> | 86% | 56,971 psi | 85% | 3009 fps | 100% |
| Vihtavuori N170 | <<locked>> | 90% | 56,492 psi | 85% | 3048 fps | 98.2% |
| Vihtavuori N555 | <<locked>> | 84% | 60,176 psi | 90% | 3064 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 60,263 psi | 90% | 3173 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 57,580 psi | 86% | 3107 fps | 100% |
| Vihtavuori N568 | <<locked>> | 92% | 60,147 psi | 90% | 3189 fps | 100% |
| Vihtavuori N570 | <<locked>> | 92% | 57,638 psi | 86% | 3199 fps | 99.2% |
| Winchester StaBALL HD | <<locked>> | 84% | 56,246 psi | 84% | 3081 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 56,782 psi | 85% | 3022 fps | 100% |
Start Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 80% | 48,892 psi | 73% | 2867 fps | 100% |
| Accurate 8700 | <<locked>> | 94% | 41,698 psi | 63% | 2822 fps | 95.5% |
| Accurate MAGPRO | <<locked>> | 80% | 51,663 psi | 77% | 3035 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 80% | 53,505 psi | 80% | 3015 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 48,820 psi | 73% | 2972 fps | 99.7% |
| ADI AR 2217 | <<locked>> | 80% | 36,216 psi | 54% | 2700 fps | 97.7% |
| ADI AR 2218 | <<locked>> | 88% | 41,698 psi | 63% | 2910 fps | 96.1% |
| ADI AR 2225 | <<locked>> | 80% | 33,475 psi | 50% | 2671 fps | 99.3% |
| Alliant Reloder-19 | <<locked>> | 80% | 53,142 psi | 80% | 3005 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 49,458 psi | 74% | 2969 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 48,109 psi | 72% | 2881 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 42,322 psi | 63% | 2838 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 55,506 psi | 83% | 3071 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 84% | 40,001 psi | 60% | 2828 fps | 95.3% |
| Alliant Reloder-50 | <<locked>> | 90% | 43,366 psi | 65% | 2894 fps | 95.9% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 46,195 psi | 69% | 2874 fps | 97.6% |
| Bofors RP15 | <<locked>> | 80% | 45,861 psi | 69% | 2900 fps | 99.8% |
| Bofors RP30 | <<locked>> | 80% | 39,320 psi | 59% | 2779 fps | 98.5% |
| Bofors RP5 | <<locked>> | 80% | 49,458 psi | 74% | 2969 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 39,653 psi | 59% | 2782 fps | 99.1% |
| Hodgdon H4831 | <<locked>> | 80% | 51,068 psi | 77% | 2963 fps | 99.6% |
| Hodgdon H4831 SC | <<locked>> | 80% | 50,183 psi | 75% | 2946 fps | 99.6% |
| Hodgdon Retumbo | <<locked>> | 80% | 41,394 psi | 62% | 2907 fps | 99.9% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,572 psi | 43% | 1781 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 51,430 psi | 77% | 2943 fps | 99.7% |
| IMR 7828 SSC | <<locked>> | 80% | 47,485 psi | 71% | 2953 fps | 99.6% |
| IMR 7977 Enduron | <<locked>> | 86% | 50,125 psi | 75% | 2890 fps | 95.3% |
| IMR 8133 Enduron | <<locked>> | 80% | 31,024 psi | 47% | 2582 fps | 95.3% |
| Lovex D100 | <<locked>> | 92% | 54,520 psi | 82% | 2999 fps | 95.4% |
| Lovex S071 | <<locked>> | 80% | 42,047 psi | 63% | 2746 fps | 100% |
| Norma 217 | <<locked>> | 80% | 31,444 psi | 47% | 2608 fps | 97.7% |
| Norma MRP | <<locked>> | 80% | 52,852 psi | 79% | 3038 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 48,457 psi | 73% | 2972 fps | 99.8% |
| Ramshot Magnum | <<locked>> | 80% | 43,511 psi | 65% | 2835 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,341 psi | 44% | 1824 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 41,075 psi | 62% | 2877 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 37,652 psi | 56% | 2762 fps | 96.7% |
| Rottweil R 904 | <<locked>> | 80% | 53,751 psi | 81% | 2986 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 52,910 psi | 79% | 2995 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 54,520 psi | 82% | 2999 fps | 95.4% |
| SNPE Vectan SP 13 | <<locked>> | 94% | 43,801 psi | 66% | 2841 fps | 95.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 52,605 psi | 79% | 2995 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 54,955 psi | 82% | 2976 fps | 99.9% |
| Somchem S385 | <<locked>> | 80% | 53,171 psi | 80% | 2966 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 46,644 psi | 70% | 2841 fps | 100% |
| Vihtavuori N170 | <<locked>> | 84% | 45,934 psi | 69% | 2854 fps | 95.8% |
| Vihtavuori N555 | <<locked>> | 80% | 52,765 psi | 79% | 2959 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 52,243 psi | 78% | 3045 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 80% | 43,656 psi | 65% | 2858 fps | 98.9% |
| Vihtavuori N568 | <<locked>> | 80% | 38,754 psi | 58% | 2785 fps | 96.5% |
| Vihtavuori N570 | <<locked>> | 84% | 42,873 psi | 64% | 2910 fps | 95.9% |
| Winchester StaBALL HD | <<locked>> | 80% | 48,283 psi | 72% | 2959 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 49,284 psi | 74% | 2900 fps | 100% |
ᴾ possible press load - work up slowly to this load while watching for signs of excessive pressure.
This overview compares 58 powders for 7.21 Firebird loaded with the .284 | 160gr | CutEdge LZR MAX. Hodgdon Retumbo delivers the highest muzzle velocity at 3,228 fps; across all powders the maximum-charge window runs from 1,985 fps to 3,228 fps. Accurate 8700 gives the best case fill at 100 %, and 58 of the 58 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 1:8.0 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. 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.