VOPO breech block
 

Picked up a 1937 Luger the other day. It's a VOPO with mismatched parts. The breech block is mismatched to the gun. It is very tight. Ultrasonically cleaned and lubed very well so it's not crud. With just the breech block in the barrel extension it takes a hard press with my finger to close the breech. Should I lap with compound to free up tolerances?

I'd shoot it and see if it sticks first...

I just built up a parts shooter and the breechblock is very tight also....