Macro to delete rows matching certain column criteria

site: https://ccm.net/faq/6261-excel-a-macro-to-delete-rows-with-specific-values

I have reviewed this VBA code and it keeps getting stuck when it reaches the "NumRows = rngSrc.Rows.Count" notation. The instructions at the top indicate that this macro runs through 30,000 rows and I see that that number is specifically stated in the code; however, the number of rows in my file will vary month-to-month (currently, it has 265,000 rows and next month may be 50K+/- rows. I am not a VBA coder and I struggle with trying to figure out what all the notations mean. Overall, I need to search down column X for find the text "CA" and delete all the rows that DO NOT match this value. So, out of 265K rows, it should only keep about 30K rows. Any help on this would be greatly appreciated.

Thanks.