upper slide issue with Browning Buckmark

[drf]

I ordered a new upper aluminum slide for my Buckmark camper. Didnt want to get the plastic one again because of the cracking issues. Anyway, i have to install the new rear sight and i'm having problems trying to insert the new pin to hold the sight in place and the pin is extemely tight for the sight hole. I dont want to damage anything trying to force the pin in. I ordered the slide directly from Browning Any recomendations would be greatly appreciated. drf