I think there were many rifles in existence capable of shooting consistent MOA or better groups with jacketed bullets long before the bullets were commonly available to prove it (from the shops of Niedner, Pope, et al), making bullets the key in the search for that Grail. Bullet making technology caught up when Speer, Sierra Hornady, Sisk, etc. hit their stride in the 50's and 60's. That of course is just my opinion, and references over the counter availability, not the market served by reclusive detail-oriented custom bullet makers back then.
