The first line is Prime WA M4, the next kanji character says "use"....
Someone else on another forum pointed it out.....BTW the site does do business outside of Japan, but they are pretty expensive....(I bought some pistol parts for WA from them)...
Anyone who buy that will be my hero...lol Fully functioning ambi-dextrous SR-16 receiver for GBBR.....holy grail....lol