Solid mouse (C57BL/6) WT primers
I have settled for two GAPDH primers with a short amplicon (~50bp):

&gt;gapdh_rv3 &lt;unknown description&gt;
GAGACCTGAATGCTGCTTCC 

&gt;gapdh_fw3 &lt;unknown description&gt;
CTCCATTTCCCCTGTTCTCC


They provide consistent and good controls, as seen here (lower bands):