Don't know what range you hang around at but I've sure never heard that story before. Nor do I believe it. The least accurate Model 7 I've ever seen wears a one piece base. ALL the old ones have to as there is no two piece bases for them. ALL the newer ones I've seen and which have come home with me wore two piece bases and all were more accurate. I think you need to find a different range to listen to gossip on.
While some ranges have more than their share of Rookies who believe more in Urban Legends, the range I frequent has Lifetime Shooters, Bench Rest Competitions, and probably total years of experience that would add up in the thousands of years around guns, sights and scopes.
I can assure you that in
some cases, a one piece base answers a accuracy problem. That isn't folklore, that is a fact.
Come up to Pennsylvania sometime, and I can introduce you to the people at the range I frequent. You can tell them your theory about their range expertise. And maybe you can show them how you do it. Then we'll go to the Clubhouse and have a few.