Out of 105 Needhams in the database, there are 34 known to have the hole in the center position and 65 are known to have the hole in the end position.
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Hammer #132
At some point in the assembly of Needhams, it was found firing pins were breaking. A change in the firing pin was made and a new location was found for the firing pin retaining screw. Hammer #132 up to now has been the only one found with both holes in the breech block and was thought to be an anomoly. But now a second one has been found.
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Hammer #277
After using a borescope I discovered the way the breech block is drilled it allows more meat for the threads for the firing pin screw. Because of this, it has been determined on this Needham the end hole was the original hole and the center hole was drilled later.
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