how to determine if subsonic
You have mentioned several times on this forum to make sure to use supersonic rounds in the 155 - 165 grain 40 caliber Speer Gold Dots.
I do not have access to a chronograph , I just thought all the gold dot rounds were standardized and the only difference in them was the grain.
My box says:
40 S&W 165 GR. GDHP
This is a 50 round box I purchased online from ammunitiontogo.com
How do I know if these are the full power rounds?
I was carrying 180 grain but have switched to the 165 as per your recommendation.