Load Specifications
Load data in caliber .221 Rem. Fireball with .224 | 55gr | Sierra SBT GameKing bullet and 16 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2207, ReloadSwiss RS 36 and Vihtavuori N120.
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: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AR 2205 | <<locked>> | 82% | 40,814 psi | 88% | 2615 fps | 99.9% |
| ADI AR 2207 | <<locked>> | 98% | 41,582 psi | 90% | 2825 fps | 99.3% |
| Alliant Reloder-7 | <<locked>> | 96% | 41,771 psi | 90% | 2762 fps | 96.6% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 28,543 psi | 62% | 1745 fps | 100% |
| IMR 4198ᴾ | <<locked>> | 100% | 40,669 psi | 88% | 2743 fps | 96.5% |
| IMR 4227 | <<locked>> | 88% | 39,943 psi | 86% | 2684 fps | 97.9% |
| Lovex D060 | <<locked>> | 82% | 41,205 psi | 89% | 2723 fps | 96.6% |
| Lovex S053 | <<locked>> | 90% | 40,408 psi | 87% | 2700 fps | 99.9% |
| Norma 200ᴾ | <<locked>> | 100% | 41,234 psi | 89% | 2815 fps | 96.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 27,862 psi | 60% | 1785 fps | 100% |
| ReloadSwiss RS 36 | <<locked>> | 90% | 40,785 psi | 88% | 2746 fps | 98% |
| Shooters World Buffalo Rifle | <<locked>> | 82% | 41,205 psi | 89% | 2723 fps | 96.6% |
| Shooters World SOCOM | <<locked>> | 82% | 41,075 psi | 89% | 2690 fps | 97.3% |
| SNPE Vectan BA6 1/2 | <<locked>> | 92% | 39,798 psi | 86% | 2566 fps | 100% |
| Vihtavuori N110 | <<locked>> | 84% | 40,451 psi | 87% | 2648 fps | 100% |
| Vihtavuori N120 | <<locked>> | 98% | 41,901 psi | 90% | 2785 fps | 99.8% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AR 2205 | <<locked>> | 80% | 38,667 psi | 83% | 2572 fps | 99.7% |
| ADI AR 2207 | 13.7 gr | 84% | 27,050 psi | 58% | 2480 fps | 95.3% |
| Alliant Reloder-7 | <<locked>> | 92% | 37,463 psi | 81% | 2677 fps | 95.4% |
| Hodgdon TrailBoss | <<locked>> | 80% | 20,682 psi | 45% | 1558 fps | 100% |
| IMR 4198 | <<locked>> | 96% | 36,550 psi | 79% | 2654 fps | 95.2% |
| IMR 4227 | <<locked>> | 80% | 31,227 psi | 67% | 2487 fps | 95.3% |
| Lovex D060 | <<locked>> | 80% | 39,030 psi | 84% | 2674 fps | 96% |
| Lovex S053 | <<locked>> | 80% | 30,037 psi | 65% | 2470 fps | 98.3% |
| Norma 200 | <<locked>> | 96% | 36,100 psi | 78% | 2713 fps | 95.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 20,291 psi | 44% | 1598 fps | 100% |
| ReloadSwiss RS 36 | 13.9 gr | 82% | 31,488 psi | 68% | 2539 fps | 95.3% |
| Shooters World Buffalo Rifle | <<locked>> | 80% | 39,030 psi | 84% | 2674 fps | 96% |
| Shooters World SOCOM | <<locked>> | 80% | 38,130 psi | 82% | 2631 fps | 96.6% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 28,863 psi | 62% | 2349 fps | 100% |
| Vihtavuori N110 | <<locked>> | 80% | 35,926 psi | 77% | 2562 fps | 100% |
| Vihtavuori N120 | 13.1 gr | 80% | 24,598 psi | 53% | 2372 fps | 95.3% |
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 16 powders for .221 Rem. Fireball loaded with the .224 | 55gr | Sierra SBT GameKing. ADI AR 2207 delivers the highest muzzle velocity at 2,825 fps; across all powders the maximum-charge window runs from 1,745 fps to 2,825 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 16 of the 16 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (320 MPa), the top charges use 60–90 %, leaving at least 10 % headroom. The 55.0 gr projectile in 0.224" calls for a 1:12.0 twist; slower twists will usually not stabilise this weight. Hodgdon TrailBoss, IMR 4198, Norma 200 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 2207, ReloadSwiss RS 36, Vihtavuori N120 rank at the top here: for .221 Rem. Fireball with the .224 | 55gr | Sierra SBT GameKing 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.