Load Specifications
Load data in caliber .221 Rem. Fireball with .223 | 45gr | Merlin Virtus bullet and 11 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Lovex S053, Vihtavuori N110 and SNPE Vectan BA6 1/2.
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>> | 84% | 40,321 psi | 87% | 2940 fps | 97.4% |
| ADI AR 2205 | <<locked>> | 86% | 40,059 psi | 86% | 2854 fps | 98.8% |
| ADI AR 2207ᴾ | <<locked>> | 100% | 36,680 psi | 79% | 2979 fps | 96.4% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 26,136 psi | 56% | 1906 fps | 100% |
| IMR 4227 | <<locked>> | 94% | 40,118 psi | 86% | 2936 fps | 95.7% |
| Lovex S053 | <<locked>> | 96% | 40,770 psi | 88% | 2976 fps | 99% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 25,150 psi | 54% | 1942 fps | 100% |
| ReloadSwiss RS 36 | <<locked>> | 96% | 40,741 psi | 88% | 2999 fps | 95.8% |
| SNPE Vectan BA6 1/2ᴾ | <<locked>> | 100% | 41,307 psi | 89% | 2871 fps | 100% |
| Vihtavuori N110 | <<locked>> | 90% | 40,480 psi | 87% | 2936 fps | 100% |
| Vihtavuori N120ᴾ | <<locked>> | 100% | 37,188 psi | 80% | 2949 fps | 97.7% |
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% | 34,722 psi | 75% | 2818 fps | 95.9% |
| ADI AR 2205 | <<locked>> | 80% | 33,301 psi | 72% | 2703 fps | 97.3% |
| ADI AR 2207 | <<locked>> | 98% | 33,982 psi | 73% | 2913 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 18,695 psi | 40% | 1703 fps | 100% |
| IMR 4227 | <<locked>> | 92% | 37,884 psi | 82% | 2887 fps | 95% |
| Lovex S053 | 13.3 gr | 84% | 28,485 psi | 61% | 2677 fps | 95.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 18,115 psi | 39% | 1739 fps | 100% |
| ReloadSwiss RS 36 | <<locked>> | 94% | 38,522 psi | 83% | 2949 fps | 95.1% |
| SNPE Vectan BA6 1/2 | 11.6 gr | 80% | 24,076 psi | 52% | 2477 fps | 99.6% |
| Vihtavuori N110 | 12.1 gr | 80% | 29,776 psi | 64% | 2700 fps | 99.7% |
| Vihtavuori N120 | <<locked>> | 94% | 30,951 psi | 67% | 2795 fps | 95.7% |
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 11 powders for .221 Rem. Fireball loaded with the .223 | 45gr | Merlin Virtus. ReloadSwiss RS 36 delivers the highest muzzle velocity at 2,999 fps; across all powders the maximum-charge window runs from 1,906 fps to 2,999 fps. ADI AR 2207 gives the best case fill at 100 %, and 11 of the 11 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (320 MPa), the top charges use 54–89 %, leaving at least 11 % headroom. The 45.0 gr projectile in 0.223" calls for a 1:11.5 twist; slower twists will usually not stabilise this weight. ADI AR 2207, 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. Lovex S053, Vihtavuori N110, SNPE Vectan BA6 1/2 rank at the top here: for .221 Rem. Fireball with the .223 | 45gr | Merlin Virtus 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.