OK, now some things to check. First, take a sized deprimed case and put it in the chamber. Close the lever and push on the pin. If it sticks in check your extractor pressure and look at the tab on the bottom of the bolt to make sure it is not broken off or bent. Remove the links and just push the bolt forward all the way forward until the extractor snaps over the case rim and see if the extension sticks when you push it in with the empty deprimed case in the chamber. If it does, the take out the bolt and inspect for burrs or the bolt hole being ovaled. You should be able to insert the extension into the bolt and twist it 360 degrees with no binding. If the 66 links work fine in the 66 and you put the Henry links in and the extractor isn't snapping over the rim that means the Henry links are slightly shorter and you are increasing the head space on your 66. You don't want to do that. Again, what is the diameter of the firing pin extension? Take a caliper, lower the lever so it is sticking out of the receiver and measure it.