Inusuit
Member
My LGS installs sights for free if I buy from them. Their prices for sights are lower than most retail vendors.
Can't answer WHY they are so tight from the factory, however replacement sights, to be installed properly, need to be carefully fitted to the individual dovetail. The male dovetail on most replacement sights are slightly over sized to allow them to be fitted to each individual sight dovetail cut. Dovetail cuts will vary, even with CNC machines, due to tool wear and even slide variances cause tolerance stacking. Yes most sights can be forced into the dovetail, but it's just not the proper way to do the job.
I don't know of any mass market guns that have hand fitted sights. Identical sights are grabbed out of a bin, and driven into identical slides.
If you plan on changing sights >2 x, buy the pusher