It looks like the only higher capacity magazine Savage is offering that fits their "Premium" metal DM system is the 10 round 308 for the FCP series (NOT the Axis or the AI pattern mags) - part number 110930. If they offer the same style of magazine in 223 I can't find one listed anywhere.

I was able to successfully and quite easily convert said 308 magazine into a 7 round 300 WSM by swapping the top piece and follower, using the spring from the 10 round mag attached to the 300 WSM follower. I am sure some of you have done that. Works great. Sure beats a measly 2 rounds in the mag!

Can you take that same 10 round 308 mag and swap out the top piece and follower from a 223 DM, also using the same longer folded spring that comes with the 10 round 308, or is there something different about the 223 DM mags? ( I don't have one to look at.)