Re "I find it intersting that Kynoch brass fits perfectly, yet new brass doesn't. Should be able to figure it out. This means there is a different measurement somewhere that needs to be found and solved."

Just remember that the 404 dimensions have changed over the years and chambers of early guns can be particularly hard to sort out brass for.

It was either here or on AR that someone actually posted a really good summary of what changes occurred and by whom.

Some 404's are notorious for sorting out what fits and what doesn't.

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