Wattgate IEC does not fit tight.

Check out https://alexsoundtech.com/iego. They distribute several products including Iego (eye-ee-go, that's a capital I) power cord connectors The Iego IEC connectors are very tight gripping. The base metal is pure copper not brass or phosphor bronze.I am using the un-plated copper and the gold plated connectors on several of my cords.

They can be found on ebay and Alex Sound Technology is the seller. 

Do not simply key in Iego on ebay, you will be taken to the "Lego" toy blocks. Instead key in "Iego IEC connector" (again, capital I not lower case L) to get to the right place.

I am continually frustrated by this issue, it is such a poor design. Any metal with high conductivity is too soft to maintain tension. Are there any vendors that spring load their plugs?

@jea48

I go into the details of the Wattgate in my blog. Essentially series of questionable choices regarding the length of the body, shortness of the pins and the contact method resembling the prongs of a backstab outlet connection, in addition to poor materials.

At the very least, that body needs longer pins.

Really, I try to avoid ever saying "don't get this gear, it's bad" on this forum, or anywhere and prefer listeners to make their own choices.  Wattgate is a rare exception and I think consumers are safer and better off with a $5 part from the hardware store.