Need Help from the Revolver Experts

[wheelie]

Check more than one and I think you will find they are not all tapered like that.

Sometimes there is a restriction where the barrel is connected to the frame (from tightening the barrel to get it to turn up) then it loosens up once you get past the constriction. But each gun will likely be different.

In any event, you want the bullet (when it gets there from firing) to be at least groove diameter or a smidge bigger.

Slugging the barrel and then trying that slug in the cylinder throat might be illuminating.

The happy spot is where the bullet enters the throat snugly and the grooves snugly - a bullet a bit larger than either hole through which it passes.

If the throats are smaller than the groove diameter you got a problem, 'cause you'll have a bullet entering the barrel that is too small - its been sized down in the cylinder throat.

[Tom E]

Check more than one and I think you will find they are not all tapered like that.

I did. You might read post #23. This is based on the barrel in my 625-8 and a new 5" 625 barrel I bought. Easier to check on a barrel not screwed in the frame. Slide a pilot in either barrel and it's painfully obvious the muzzle end is smaller.

[cas]

FWIW tight throats usually increase pressure and give a bit more speed. It's not uncommon for muzzle velocity to be slightly lower after honing/reaming throats.

Could your velocity issue simply be a powder/primer lot variance?