Load Specifications
Load data in caliber 7 x 72 R with .284 | 105gr | IBEX Viper bullet and 14 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are SNPE Vectan Tubal 5000, Vihtavuori N135 and ReloadSwiss RS 14.
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: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 88% | 36,303 psi | 89% | 2799 fps | 99% |
| Accurate 4064 | <<locked>> | 90% | 36,274 psi | 89% | 2815 fps | 96.9% |
| Alliant AR-Comp | <<locked>> | 84% | 35,984 psi | 89% | 2825 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 33,779 psi | 83% | 1890 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 36,593 psi | 90% | 2851 fps | 98.3% |
| Norma 202 | <<locked>> | 84% | 35,186 psi | 87% | 2753 fps | 96% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 33,997 psi | 84% | 1936 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 35,433 psi | 87% | 2664 fps | 95.9% |
| SNPE Vectan Tubal 5000 | <<locked>> | 90% | 36,347 psi | 90% | 2710 fps | 97.4% |
| Somchem S335 | <<locked>> | 82% | 34,998 psi | 86% | 2674 fps | 96.8% |
| Vihtavuori N133 | <<locked>> | 82% | 34,969 psi | 86% | 2677 fps | 98.4% |
| Vihtavuori N135 | <<locked>> | 88% | 36,085 psi | 89% | 2789 fps | 98.9% |
| Vihtavuori N140 | <<locked>> | 86% | 35,389 psi | 87% | 2736 fps | 96.5% |
| Vihtavuori N540 | <<locked>> | 88% | 36,274 psi | 89% | 2772 fps | 96.1% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 80% | 28,543 psi | 70% | 2592 fps | 96.9% |
| Accurate 4064 | <<locked>> | 86% | 32,300 psi | 80% | 2713 fps | 95.5% |
| Alliant AR-Comp | <<locked>> | 80% | 32,097 psi | 79% | 2723 fps | 99.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,251 psi | 62% | 1693 fps | 100% |
| IMR 3031 | <<locked>> | 80% | 30,676 psi | 76% | 2687 fps | 96.3% |
| Norma 202 | <<locked>> | 82% | 33,301 psi | 82% | 2700 fps | 95.3% |
| ReloadSwiss RS 14 | 11.9 gr | 80% | 25,295 psi | 62% | 1732 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 33,504 psi | 83% | 2615 fps | 95.2% |
| SNPE Vectan Tubal 5000 | 34.4 gr | 84% | 30,545 psi | 75% | 2559 fps | 95.4% |
| Somchem S335 | <<locked>> | 80% | 33,011 psi | 81% | 2621 fps | 96.1% |
| Vihtavuori N133 | <<locked>> | 80% | 33,054 psi | 81% | 2628 fps | 97.9% |
| Vihtavuori N135 | 32.8 gr | 80% | 28,485 psi | 70% | 2585 fps | 96.7% |
| Vihtavuori N140 | <<locked>> | 84% | 33,301 psi | 82% | 2680 fps | 95.7% |
| Vihtavuori N540 | <<locked>> | 86% | 34,185 psi | 84% | 2717 fps | 95.4% |
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 14 powders for 7 x 72 R loaded with the .284 | 105gr | IBEX Viper. IMR 3031 delivers the highest muzzle velocity at 2,851 fps; across all powders the maximum-charge window runs from 1,890 fps to 2,851 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 14 of the 14 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (280 MPa), the top charges use 83–90 %, leaving at least 10 % headroom. The 105.0 gr projectile in 0.284" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. 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. SNPE Vectan Tubal 5000, Vihtavuori N135, ReloadSwiss RS 14 rank at the top here: for 7 x 72 R with the .284 | 105gr | IBEX Viper 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.