OK......bought a new globe front sight. Knocked out the old one (very tight) and have the new one about halfway in. However, I'm at the point that it is so tight that I'm going to have to remove some metal somewhere for it to fit. I'm assuming that I remove the metal from the easy to replace $50 front sight dovetail rather than the $650 (installed) barrel. Any hints or words of wisdom on this work would be appreciated. For instance, how do you decide where to remove the metal? Go slowly is a given. Thanks.

There are no chiseled in stone rules on barrel dovetail dimensions and sight dovetail specs.  I like to have them slip in about half way, then use a brass tipped punch to seat them...going in right to left as seen from the shooter's standpoint.  If the dovetail is cut correctly, I would lightly take off material from the back dovetail section of the sight, leaving the front alone.  Use a dovetail file, a triangular file with at least one safe (non cutting) side.  Go slow, it's really easy to take off too much.

David

Just to add to what I said, the "standard" 3/8" dovetail end mill for gunsmithing purposes is .359" in diameter.  I've measured sight dovetails that were as small as .350" and as large as .395"...all sold as having 3/8" dovetails!  Just remember the first rule of gunsmithing...always work on the cheapest or most easily replaced part first!   

David

If, after measuring the sight and determining that there is enough vertical clearance for any portion of the sight that overhangs the barrel front and aft of the dovetail along the bore axis, my preferred method is to slap a piece of 400 grit wet or dry paper on a layout block, though any good flat surface free of imperfections will do. 

Then slide the bottom of the sight back and forth across the paper, keeping it flat during the process. The metal removal is a bit slower, and it helps prevent you from going too far when you're close to achieving that good fit. This also prevents you from filing an improper angle that causes the sight to be skewed to the left or right of the bore axis when finally installed. 

A dovetail is a triangle, and if you remember any of your high school geometry, removing material from any side of the triangle reduces dimensions in all directions.