I presume you mean the Mini-14, standard model, with the GI type rear sight. It wiggles in the mount! I got a Eagle polymer replacement sight (just the 'L'), had to file it just a bit, and it gave a very tight fit that won't wiggle. Then I got a drill and a bit just bigger the apendature hole in the old sight 'L', and drilled a bit larger one. You can keep useing larger drill bits till you get it the size you want. Warning, once you drill the hole, you can't put it back the way it was.
I think a few companies make replacement 'L' s for the Mini-14. I think I paied 10 bucks for the sight. Comes in a package.
Deaf