[DCRTorr]

Hello, I have a Pedersoli Sharps 1874 'Q' model in 45-70. It came with factory tang rear sight and globe front sight. I replaced the blade front sight w/ the globe sight and noticed that both tapped pretty easily out of / into the dovetail (not a lot of friction).

I was testing some loads this week and getting good groups (1 1/2 - 2 MOA at 200 yds) when the rounds started to walk to the left & off the paper. As far as I can tell, the rear sight wasn't the problem. The front sight appeared to have slid in the dovetail, just under the effect of recoil -- I'm confident I didn't bump it. It happened while I was shooting a 5-shot string w/ the rifle set in front & rear sandbags.

My question is: what's the best way to tighten up the sight in the dovetail? I've heard of a couple of methods:
-- use a center punch to dimple the bottom of the dovetail groove, thereby raising some of the steel around the indentations that increases friction w/ the sight base.
-- Use a flat punch along the outside edges of the dovetail (with the sight in place) to tighten up the sight in the groove.

Or, should I take it to a gunsmith for some sort of repair?
Thanks