Having made 2 and broken them both it's time for a real one I think!

There's a deep well socket you can modify simply. Maybe try that first?

"Got this idea from someone else, but it worked great so I thought I’d post it here.  Basically, it involves converting a nut driver to a Lee-Enfield firing pin removal tool.

The concept is so simple that it actually doesn’t need much elaboration.

Still, here’s what worked for me:

After making a few measurements and checking them against various nut drivers at Lowes, I bought the Klein Tools 3/8 deep well nut driver shown below for $4.68 plus tax.  (My local Home Depot also carries this same tool at a slightly higher price)

It took maybe 15 minutes using a Dremel with a cut off wheel to fully modify the nut driver.  Surprisingly, the steel was quite a bit softer than I expected – the Dremel cut through it very easily.  This nut driver is chrome plated, so forget using a hacksaw or file on it!

For my particular firing pin, I cut the two tabs on the end to the tool to about .12” for both the width and depth.  You don’t want to make the tabs too small since they’ll break off easily.  However, I suggest you don’t try for a snug fit in the firing pin notches either since, if the tabs do break off (and they might), you may have a difficult time getting the broken-off tabs out of the bolt.

Note that the hole in the shank of the nut driver needs to be deep enough to let the front of the firing pin feed into it.  Some aren’t.  The above nut driver has a hollow shank to begin with.

Making one from a good quality tool steel would be a good idea.