Ted referred to a letter from John Olin about this, and suggested that durable rib soldering on the 21 wasn't an insurmountable task, but more exacting to get right.

If this is true and came to Winchester's attention after the 21 was in production for some time, I wonder if they gave it more attention and reduced the incidence in later production. I'd like to hear what Andy could tell us about what he sees.