On a lot of these older small tenon front sight slides, armorers used to silver solder the heavier target style front sights on to avoid them shooting loose. You do need a special staking tool to use the factory installation method, and Jim is correct that some technique is involved. I wound up cutting up and brazing a modified C-clamp to a cheap set of vice grip pliers and shaping and hardening a staking tooth and mounting it to the plier jaw. This lets me clamp the sight into position so the jaw can upset the tenon enough to get a grip in the slide without the sight popping up any. It works OK, but if you don't have the tooling, the suggestion to get a target style front sight dovetail milled in is a good one. That will let you exchange a number of sights, in case you don't like the first one you get?
Gunsite Orange Hat Family Member
CMP Certified GSM Master Instructor
NRA Certified Rifle Instructor
NRA Patron Member