I've never heard of K&P, bit I've learned this lesson twice in my rifle building quest. The smith that built my first custom said that he only worked with Hart barrels. When I did the research, it seemed like Hart had been around a while bit was not the newest shiniest most popular stick around. I wondered why he wasn't recommending Barlein, Kreiger, or Proof, or one of those. I trusted his knowledge and experience and got a great result.
Second time was more recently. I wanted a 22 CM, and the 'smiths that I have come to trust said that he would chamber anything that I brought to him, but if he was going to order the barrel, it would be a Lothar Walther. I had never heard of them, bit again research said that.they had lots of great products and were especially known for their. 224 bore barrels, and again it shoots lights out.
If you have someone you trust, and they have a brand that they trust.....go with it, and then tell is how it went.