Changing out sights on a gen 5 G19 - rear sight is too tight

I bought some ameriglo night sights (not the ones specifically called Gen 5), and am having a ton of trouble getting the rear in. I've been using a non-marring hammer to punch in the rear, but it's stopped half way through, and I'm afraid to keep whacking at it.I'm guessing the rear dovetail must have changed shape from gen 4 to gen 5? Is it safe to keep trying to shove it in, or can these things break? via /r/CCW https://ift.tt/2XjExVR