Would they offer an extension for single feed? So, those extensions are bases on cartridges? With short mag cartridges the cartridge sits in the middle like single stacks and would benefit more of that design.
I' decided to check the extensions on my AR10's chambered in 6.5prc (McGowen) and 7saum (X-Caliber). The 6.5 has duel feed ramps and the 7saum has single feed. I guess I'll find out if 1 or both operate as designed?
@Mike D Texas you could get custom chambered? Also about the re-chambering of what you do have could pose a problem with headspacing? From what I've seen on how it's done the gas port is reamed after the extension and headspacing is finished as to correctly dial in the port. This keeps port at 12 o'clock with the index pin on extension and feed ramps at 6 (respectively).