I had the same problem a couple years back after I switched to a different set of domes. I kept burning the o rings up. I eventually found the problem to be my domes werent seating properly on my cylinders. The lip on the bottom side of the dome wasnt tall enough causing the combustion to seep past the aluminum sealing lip on the dome, and burn my o rings up.
I was running a vitos hemi head and trying to run noss domes, which are supposed to be "interchangeable" (well, noss and pro design are interchangeable, and vitos and pro design are interchangeable, so I figured it would work...it didn't). I ended up having to send noss my original vitos domes, he figured the problem out and custom made me a set of domes that would work. Havent had a problem since.