The last was a shim shaped to the receiving end inside the tang.
The picture shows a shim, both free of the action (above) and one visible inside the closed action.

You have to experiment with lengths going toward the breach, both top and bottom.    
Too short on bottom and the tail of the breach block will travel off the shim and risk binding or butting into the shim the next time you close the block.
Too long on top and the block will bind against the top when you open it or travel beyond the shim end-point.
You also have to experiment with thickness, so lock-up is not too tight or too loose.   
Start with brass, then when you have proper thickness, form from a stainless shim.

If someone shaped a ram on a press to form the stainless shim to the circumference of the round receiving end of the tang the fit would be optimal for stability when the action was operated.

Hey Rodney,   Never heard it put that way but I like it.   

Vall passed the obsession on to me.   Got 6-7 I’m determined to pass on and three I’ve determined to sell.    But listing even those three is proving hard to do.

Glad this topic came up and people have posted their various tricks to tightening up the actions. I really love the Ballard rifle so much there's almost nothing I wont do to get one back to shooting again!
Sending my #3F Ballard off to Al Springer soon for a facelift, and a new GM .22LR heavy barrel. I'll set the old barrel and forearm aside just in case I ever sell it and someone wants to have it relined and put back on.

I haven't thought much about Ballard actions for a number of years. All of mine are working just fine. But in the middle of the night I woke up and had this thought about Sgtdog's fix vs. mine.
  So a little background; since way before my time, there has been an idea floated around among gunsmiths and others regarding loose Ballard's. That idea is that the "snap" holding the lever up is from interference in the breechblock fit between the barrel face and what I call the "shoulder" (the angled recoil surface, I think 20 degrees to barrel face). The wedging action as the block moves up is what makes Ballard's seat cartridges so well. It is true that setting the barrel up so there is "crush" as the block closes will give a loose action the "snap" that holds the block and lever up. The "snap" is when the link goes over center. 
  However, this is not where the action originally got it's "snap".
This can easily be seen on any unmolested, pristine action. Pull the barrel and it will still "snap". How this happens is the interference comes from the pressure created when the link pushes up the block into contact the flat surface running front to back. If you look at the photo Sgtdog posted, you can see the contact area just in front of where the front tang sight hole is. 
  Where I am going with all this is that a number of steps are involved in a specific sequence when a Ballard is built. The last  thing to do is to square the breechface to the reciever. 
  Obviously, any attempt to tighten up a loose gun may end up with the breech block face out of square to the barrel. The gun will still work but may affect accuracy and case life. 
  So now we have two methods that are putting the tension back on the action. The "Patent repair" by pushing the back of the blocks down and SgtDog's by pushing them up. 
  So, if you have the barrel off the action, use a depth mike (not a caliper!) and take 2 readings through the barrel hole from the barrel face to the block. One at the 12 o'clock of the hole and one at 6 o'clock. You can now choose which method will help straighten it out if those surfaces are not parallel. Be sure to have some pressure to ensure the block is back against the recoil shoulder when you measure. 

SgtDog0311, A salute from me, Thanks for adding to the collective knowledge of these rifles.

Kootne


   

Thank You Kootne!

I’ve heard fellas way more knowledgable than me talk about the points you raise.    In that instance it was a Rolling block and the ‘out-of parallel’ was enough to deform the brass in fired cases enough to be felt when next they were chambered.    So you raise a good point.    One I had not considered.

I put an 8-40 shop made set screw into the rear sight socket. It was about 3/8” long.  There was plenty of room left for the tang sight screw. It worked as advertised.  I don’t know how you could taper it to match the angle of the block however unless you did it from the inside after installing and loctiteing it 


Jack