I haven't done them on a gp100 yet, but looking at photo's of them it looks easy.
It looks like a drift sight in the front and a screwed sight in the rear.
I've done them on my M&P's and 1911, I also replaced the sight on one of my old Colts (that looks like the gp100 sight) with something like the XS sight.
They work great, I will use them on any of my guns, thats how much I like them.
The GP100 sight is pinned in and must be removed to install the new XS. I can't remember if it is XS but some revoilver sights come without the pin hole to allow the smith to cut the hole for proper fit. Just an FYI.
The GP100 sight is pinned in and must be removed to install the new XS. I can't remember if it is XS but some revoilver sights come without the pin hole to allow the smith to cut the hole for proper fit. Just an FYI.