The mag fed option is for first strike, the hopper is for the regular stuff. That's the whole reason I bought the marker...otherwise what's the point? Plenty of other cheaper mag fed options out there....
Different Halos use different mechanisms. Mine is a Halo B circa 2004; it uses a break beam eye. It's loading fine (my concern is it might be loading too aggressively for the DAM), and it works fine on my automag...the problem is most definitely with the DAM doing something funny in the breach, not the loader failing to keep up, remember the DAM has eyes, it won't fire partially loaded.
Cleaning it again tonight I noticed that the bolt actually rests really far back, anyone else's DAM look like this?
Here's my mag (bolt in the cocked position) for reference (no roll back to speak of):