If you use a lighter bullet with the appropriate powder I suspect the only thing that might happen is short cycling.
Please please please read the posts above? It's a dedicated, triple pillared rifle designed around the 190gr projectile. Mr. McCoy had been building winning competition rifles for the US Navy shooting teams since the 60's. I suspect that he might have known what he was doing?
I understand perfectly. It's a good bet that you have no idea who the builder was, his history or records. The oprod and the entire rifle was built for the 190. Period. McCoy knew exactly what he was doing,. The fact that it's all explained in detail in the video he made for each individual one of these three rifles and the fact that the other two proved themselves at Perry long ago is the underscore that his rifles perform as intended. And using 190s, as specified by him.
My only question at the outset of all this was about what less expensive projectile profile I could use for that purpose besides the expensive SMK 190s.
I got my answer. The rest is all conjecture from different reloaders that means nothing to the build and intent of the rifle.
I'm in no position to second guess that master rifle builder, but I am a shooter, and a decent one at that.