26 round Duramag Fail to Feed

[southpaw]

The first time using two 26 round Duramags, both gave me intermittent fail to feed stoppages. I only loaded 25, but was never able to shoot more than 8 or so rounds before they jammed. Every time this happened, the bolt was stuck on top of the mag with the round caught at the end of the feed ramps.

When I switched to Elander 17rd mags loaded to 15, no more issues.

Anyone have any suggestions on how to fix this?