Replacement for AI .223 magazines?

While I haven't tried them with 300BO, I've had the best luck with the accurate 223 mags in multiple 223 bolt rifles.

The MDT 223 plastic mags are cheaper and work ok too, but they take substantially more bolt effort to strip the first few rounds out of a full mag compared to the accurate mags, not sure if it's a feedlip geometry issue or it's just the kind of plastic used causes lots of drag on the case when the mag is nearly full.

I have not tried the MDT metal 223 mags yet, so can't comment on those.

I really like Accurate mags for 223. Metal body with polymer inserts. You can use a round file to lengthen the front up for longer OAL and they still feed great.

I run the accurate mags and the have been flawless. The only problem with them is the price. But that’s just because I’m a cheap ass. In the end, they have been worth every penny.

MDT metal .223 mags are awesome! They have the poly insert with extended feed lips. I haven’t tried them with .300 BO but they’re great with .223

The new MagPul ones look like crap, but they seem to work very well in my Proof Elevation 223....

I have two poly MDT mags that will not run at all in my manners minichassis w/ Impact action. I have four of the metal MDT mags, and I had to slightly bend the feed lips in to make sure they feed the round straight and don’t nosedive in my action. They are finicky as hell. I wish someone would figure out a decent .223 mag with a COAL of 2.6. I’d buy 5 of them.

MDT polymer mags are what I use for my Howa 1500 223 and they work perfectly. I avoid steel magazines as much as possible.