He seems surprised:
https://www.youtube.com/watch?v=CKZYAGuuA6Q&ab_channel=NickShabazz
A commenter added this:
"It goes without saying, a solid stop pin is stronger than a hollow one. The stop pin is subject to considerable impact force when the blade opens. I have heard of at least one knife manufacturer that started out using hollow stop pins and switched over to solid when they had incidents of failure."
https://www.youtube.com/watch?v=CKZYAGuuA6Q&ab_channel=NickShabazz
A commenter added this:
"It goes without saying, a solid stop pin is stronger than a hollow one. The stop pin is subject to considerable impact force when the blade opens. I have heard of at least one knife manufacturer that started out using hollow stop pins and switched over to solid when they had incidents of failure."