Quote History
Neat idea. I'm all thumbs when it comes to "tapping out" pins, though, and I'd go for something like the commercially available tools.
OP, take a look at Brownell's tool
here:
On the left, is a collar that holds the bolt head by the lugs - it lines up the ejector retainer pin over a clearance hole to catch the pin. On the right is a part that lets you apply pressure to the ejector by screwing it toward the bolt. This particular tool has a movable part that supports either 5.56mm bolts (lined up in the picture) or .308 bolts.
Now put two and two together, and rig a chunk of wood that holds the bolt lugs on one end (maybe with a pair of finishing nails the right distance apart?), and has an "L" bracket to support a bolt you turn toward the bolt face. For cheap and easy, use a 1/4-20 bolt and nut, and stick a .380 case over the end to push against the bolt face. Drill a hole under the position of the ejector pin - better yet, drill one on either side (that's a limitation of the Brownell's tool). Maybe not "production" or "high volume shop" quality, but definitely doable.
In my armorer class, we learned how to use a simple bench block and another punch to hold a little pressure on the ejector when driving out the pin. No pictures handy and it's not a simple thing to explain with words, or I'd post it here... I'll try to get pictures to post.