I was wondering if anyone knew of the ranch that uses or used the M7 brand on their horses?

We have a grade tricolored paint that's somewhere around 19 years old that we know came from TX. She has this M7 brand on her shoulder. She's extremely well built and a fabulous barrel horse and fast  out of the hole.

Just curious if anyone is familiar with the brand and if so the bloodlines of horses they used get horse bred like her.