I recently picked up a well-used 10-8 police gun. When attempting to check the yoke alignment, I was suprised and disappointed to find that my guage would go less than halfway in before binding. Any idea what might be causing this, and can anyone suggest a solution?
Thanks,
Charles

Try inserting the gauge alternatively. See if the large diameter portion will enter the yoke barrel to full depth. Then try the smaller diameter end at the front of the yoke to see if the hole there is properly sized.
That'll give you some idea where the interference is.

You could have different issues. The ejector end of the yoke could be slightly off, the yoke barrel could be bent or the barrel may need some slight reaming. May not be all that bad, despite how it sounds.

Not to be snide, but this is why I take my gauges when shopping revolvers.

Thanks. It appears that the barrel is tight... not bent or anything. Guess I need a new tool

I have had to use my yoke reamer on many occasions to get the alignment tool to go into the yoke barrel when checking the yoke alignment. Use plenty of oil when reaming.

I bet the yoke has been stretched and the dia of the inside is smaller, is there one -two or three rings at the end of the yoke where the cylinder rest? If so it has been stretched to take up the excess head space.

A 5/16 hand reamer will correct the ID of the yoke tube.