Load Specifications
Load data in caliber .221 Rem. Fireball with .223 | 55gr | SUS-TAC Varmax (HPT) bullet and 14 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 36, Lovex S053 and IMR 4227.
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 |
|---|---|---|---|---|---|---|
| Accurate No. 11 FS | <<locked>> | 82% | 40,727 psi | 88% | 2635 fps | 98.5% |
| ADI AR 2205 | <<locked>> | 84% | 40,161 psi | 87% | 2546 fps | 99.5% |
| ADI AR 2207ᴾ | <<locked>> | 100% | 39,001 psi | 84% | 2720 fps | 98.3% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 27,456 psi | 59% | 1683 fps | 100% |
| IMR 4227 | <<locked>> | 92% | 40,901 psi | 88% | 2641 fps | 97.3% |
| Lovex D063 | <<locked>> | 82% | 41,452 psi | 89% | 2651 fps | 95.7% |
| Lovex S053 | <<locked>> | 94% | 41,118 psi | 89% | 2661 fps | 99.6% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 26,745 psi | 58% | 1719 fps | 100% |
| ReloadSwiss RS 36 | <<locked>> | 94% | 41,307 psi | 89% | 2697 fps | 97.3% |
| Shooters World Blackout | <<locked>> | 82% | 41,452 psi | 89% | 2651 fps | 95.7% |
| Shooters World SOCOM | <<locked>> | 84% | 39,436 psi | 85% | 2595 fps | 95.8% |
| SNPE Vectan BA6 1/2 | <<locked>> | 96% | 40,059 psi | 86% | 2523 fps | 100% |
| Vihtavuori N110 | <<locked>> | 88% | 41,147 psi | 89% | 2612 fps | 100% |
| Vihtavuori N120ᴾ | <<locked>> | 100% | 39,508 psi | 85% | 2687 fps | 99.2% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate No. 11 FS | <<locked>> | 80% | 37,536 psi | 81% | 2572 fps | 97.9% |
| ADI AR 2205 | <<locked>> | 80% | 35,607 psi | 77% | 2457 fps | 98.9% |
| ADI AR 2207 | <<locked>> | 90% | 29,327 psi | 63% | 2493 fps | 95.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 20,363 psi | 44% | 1516 fps | 100% |
| IMR 4227 | 12.4 gr | 86% | 33,953 psi | 73% | 2497 fps | 95.3% |
| Lovex D063 | <<locked>> | 80% | 39,015 psi | 84% | 2602 fps | 95% |
| Lovex S053 | 11.3 gr | 80% | 27,311 psi | 59% | 2352 fps | 96.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 19,348 psi | 42% | 1535 fps | 100% |
| ReloadSwiss RS 36 | 13.5 gr | 88% | 34,490 psi | 74% | 2556 fps | 95.3% |
| Shooters World Blackout | <<locked>> | 80% | 39,015 psi | 84% | 2602 fps | 95% |
| Shooters World SOCOM | <<locked>> | 82% | 37,159 psi | 80% | 2549 fps | 95.2% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 26,411 psi | 57% | 2251 fps | 100% |
| Vihtavuori N110 | <<locked>> | 80% | 32,343 psi | 70% | 2448 fps | 100% |
| Vihtavuori N120 | <<locked>> | 86% | 26,527 psi | 57% | 2379 fps | 95.2% |
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 21 powders for .221 Rem. Fireball loaded with the .223 | 55gr | SUS-TAC Varmax (HPT). ADI AR 2207 delivers the highest muzzle velocity at 2,720 fps; across all powders the maximum-charge window runs from 1,683 fps to 2,720 fps. ADI AR 2207 gives the best case fill at 100 %, and 21 of the 21 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (320 MPa), the top charges use 58–89 %, leaving at least 11 % headroom. The 55.0 gr projectile in 0.223" calls for a 1:8.5 twist; slower twists will usually not stabilise this weight. ADI AR 2207, Alliant Reloder-10x, Hodgdon TrailBoss 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. ReloadSwiss RS 36, Lovex S053, IMR 4227 rank at the top here: for .221 Rem. Fireball with the .223 | 55gr | SUS-TAC Varmax (HPT) they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 1680, Alliant Reloder-10x, IMR 4198 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.