Getting bored with assembling ARs, I decided I wanted to actually build something.  I purchased a M1903A3 drill rifle from the CMP and plan to reactivate it.  For those familiar with the process, you know the most difficult part is dealing with the magazine cut-off.  Luckily I got one that had a cracked weld on one side, so a dremel wheel made short work of the other side and I got the cut-off removed and the bolt out.

Before:



To avoid the receiver, I left behind a big glob of weld.  You can see what I'm dealing with between the right edge of the electrical tape (which marks the edge of the receiver) and the cut.  I'm looking for suggestions on tools and process to clean up that remaining weld to allow a new cut-off to be installed.

After:

Hard for me to see and I don't know my way around Springfields; does the cutoff protrude enough for you to clamp the receiver vertically and attack the weld with a file?

A good file will make short work of a weld, provided it's weld and not slag, and would be my first thought. And it doesn't appear to penetrate to deeply.

You would want a safety file with a non-cutting edge.

No matter what, it looks like a place for slow and steady hand work.