Has anyone used this powder when loading 5.56 cases. I tried to work up a load with this powder with 50 and 55 gr bullets and ended up with higher than normal speeds. The load data that Vihtavouri used was developed using Lapua 223 cases and a 25 inch barrel with a 1 in 12 twist, my gun has a 16 inch barrel and 1 in 9 twist. my gun averaged 2970 fps with 24.5 gr, Vihatvouri data shows 2983 with 24.3 gr. With 50 gr bullets I got 3037 with 24.5 gr, their data shows 3077 with 25 gr, I should be losing at least 300 fps with my short barrel.
I talked to tech experts from three bullet manaufactures, and got three different answers. One guy said I have a fast barrel and nothing to worry about, another said don't use those loads, another tech said the fact that I have a 9 inch twist is probably the reason, it creates higher pressures than a 12 inch twist. I don't think that using 5.56 cases would make that big of a difference, what do you guys think.
