Nice find but???? Let's clear this up. Maybe.

I hear stories that Harry used a 8 3/8" m29. Then they show Harry's m29 in the national fire arms museum it's a 6 1/2'' barrel.
Confusing?

Here's what I think. He used both. In the camera shots were the bad guy is on the ground and were looking up at Harry with the gun it's the longerv8 3/8" barrel that makes the m29 look so much bigger. The normal shots of the m29 is the 6 1/2" barrel. But that angle shot of the 8 3/8" barrel does look impressive.