Cabelas has 100gr. psp bullets for my 243. They do not say core-lokt. What is the difference and would this bullets be good for whitetails? Remington's website is not helpful.

It's the same bullet.

Why are some called pspcl and some psp

It's the variations in how the retailer writes it up in the product description. All standard construction Remington bullets are Core Lokt's, some are intended for use in tube magazines, those are usually described as either round nose or 30-30 etc.

There could be a slight variation. I have noticed that before as well, and if I am not mistaken sometimes it even has that difference printed on the box.

I got them and they are labeled PSPCL, I wish Cabelas could be more specific. Thank you for ur help.