I am working up reloads for my Ruger SRH 454 Casull. I am using Starline brass, CCI BR4 primers, H110 powder, and 400 grain Cast Performance LFN bullets. Here is the problem, I am getting a lot of missfires. The fire on the second attempt. Factory ammo as not yet missfired. Any ideas what is wrong? I am posting this on gunsmith, and hand gun forum as well.

Sounds strange. Unless its a bad run of brass with incorrect rim thickness or possibly bad primer pocket depths. Rim thickness determines headspace. Also, check your seating depth for the primers. Maybe they aren't seated far enough, or maybe too far. If they aren't seated far enough, the firing pin drives the primer in with the first shot, and fires with the second. Or, too far and the pin doesn't reach the primer properly, but that doesn't sound like the problem.
I use H110 in my Ruger also, and have never had a misfire. I use the standard Winchester WSR small rifle primers (that's what the primed Win. brass comes with).
Other than that, I don't know what could be the problem.

Thanks Ken, I am getting a lot of feed back about the possibility of poor primer seating. I will check that first.

Might want to try a primer with a softer cup. CCI cups are very hard.