Program counter build

I went way back to the beginning to build the 8-bit before I take on the 6502 with everything "in the box." I am just about to implement microcode with everything else working except one thing: In monostable mode, my program counter sometimes receives more than 1 pulse for each 1 press of the clock advance button. Any ideas on how to ensure it is only 1 shot? I'm guessing a faster rising edge pulse but I'm not sure how fast to go with the 74ls161 and I'm a bit of a noob.

First of all a big thank you. Just signed up and pledged to support you. I have to say that my professors have not explained the principle of computers to me as well as you have. Some of them wrote books on that matter and fell short. I have committed to building your SAP-1 computer, got the book , got the parts and most importantly got your videos. So keep them coming and hope more people sign up and pledge to support your contribution to the community.