Power Cable will not fully insert. Help.

Yes, for some reason that sometimes happens, as roxy54 said no big deal, it will be fine.

Dump this cable ASAP!!

Calm down Edward.

You should have received a slip of paper with the cable noting that the connector can be very tight. That’s so that an excellent grip can be achieved. In cases where it’s very tight, I believe it’s recommending that you gently insert and remove a wooden toothpick between the three pairs of gripper plates. A little at a time, as you don’t want to loosen it too much.  Just be sure the toothpick is strong enough so that it doesn't break.  Not sure about the alternative of using a small flathead screwdriver.  It's metal on metal, but then the connector to the socket is metal on metal too.

@twoleftears  I did indeed. I was unsuccessful in this but it’s probably due to my lack of experience. The first power cord took some effort but nothing like this. 
 

I love the effect these cords have and I have to say I agree with those who said power cords were as/nearly as big an improvement as speaker cable.  I didn’t and still don’t completely understand why or how, but love that they do.