Sig Sauer Magazine AR-15 5.56mm 30 Rounds Black Polymer - $21.19

They were 4.99 lil while back

Pretty sure these are the mags that run 458 socom reliably out of the box. If that's in your plans, looks like a good deal.

I’ve read that these are horrible mags, be wary.

And you can get pmags for $8 each if you wait for deals.

These look just like my IMI Defense magazines. 99% sure these are from the same manufacturer. The bolt hold open release was extremely hard to push on my receiver because the polymer top rear of the mag has too much material. I easily trimmed down the polymer with a knife and they now function great on all my receivers. Very lightweight. They are ok for range mags.

Pretty good price on these someone else will have to vouch on the dependability of these they're name brand so they can't be that bad