loose front sight

There are a few ways to fix a loose front sight. The easiest way is to place the sight upside down in a flat-topped bench vise (closed so it is almost touching the sight blade) and gently stretch the base by hammering on the bottom surface of the sight base. Alternatively, you can tap the edges of the barrel dovetail down slightly, or use a punch or nail set to make punch marks at the junction of the sight and the barrel to secure it.