Or does it vary by region. Over the last year, i have noticed no 15W-50 M1 jugs (there used to be a LOT, filling up the shelf) and i went into another Walmart recently and i even saw Supertech in the 20W-50 grade.
What is available where........? (Walmarts continue to prove themselves to be different.)
M1 15W-50 WAS a prime oil choice id consider in my vehicles, sealed by the availability at Walmart. If its no longer at Walmart i will be disappointed, since M1 15W-50, along with the 0W-40, are widely regarded as their best oils, and with good reason. (We are past the red-top SL days. I only buy oil i know i can get from somewhere. For now.)