XDm Front Sight Moving

Take the sight clear out of the dovetail.

Clean both it and the slide with alcohol or lighter fluid.

Apply Blue Lock Tight evenly to both surfaces.

Put it back centered in the slide.

Leave to to cure overnight before shooting it again.

An alternative used for years before Lock Tight was invented is to take the sight, set it upside down in loose vice jaws.

Then use a small center-punch & hammer to put some divots on the bottom of the sight.

That will raise it in the slide dovetail and tighten it.

rc

I've used peening on loose sights.

Which is exactly what RC described. I responded before reading other posts.

Peening AND blue Loctite. You won't have another problem with it.

One question that you should ask yourself is whether you will ever replace the sights. If you might replace the sights in the future, use the purple loctite 222 because it is more easily removable with handtools such as a sight pusher with peening the the slide very carefully as you do not need much. Use the blue if you don't want to peen the slide. I generally use Acetone from Walmart's beauty department as a 16 oz bottle is around 5 bucks. It works better for me for degreasing instead of alcohol or lighter fluid and evaporates just as quick.

i put Reynolds wrap aluminum foil under the sight to make a tight fit in a dovetail. Use as much or as littel thats needed. Works on steel parts. Dont know about new plastic guns.

If you don't want to totally remove the sight to apply the LocTite, use the green (wicking) product on the assembled sight after verifying zero.