I heard that these were made to allow for a better oal with match bullets something about a cutout in the center. Any info would be appreciated  thanks.

I believe they're the same or similar to the one's LRP used to sell.
The rib on the rear of the mag is wider than a std mag so as the case head can fit in there.
The rounds sit diagonally in the mag and only feed from one side.
My LRP mags hold 10rds,single stack and the max oal is 2.460"
I imagine the DPMS will be the same.Max capacity might be only 8rds though I would reckon on it being 10

Hope this helps

thanks was trying to find out if anyone who is currently selling them also. Who is lrp

DPMS have them in their catalog.
LRP was Long Range Products. I think they closed down and DPMS bought the rights

Mark

DPMS purchased the rights and the LRP company . The magazines are the lastest version that was produced by LRP. The overall  cartridge length that will fit is listed at 2.435 and is an 8 rnd capacity due to the single rnd stacking. There online catalog shows a price of 34.95