Dear John:
There has been a lot of confusion regarding the method the Europeans typically spec. things and the way we do.
The conversion formula for MM to inches is:
MM X .03937 = inches
Bore size (land to land) per 1913 Specs. as quoted above:
Maximum 8.86mm X .03937 = .3488 inch
Minimum 8.82mm X .03937 = .3472 inch
Groove size (groove to groove) per the 1913 Specs. as quoted above:
Maximum 9.11mm X .03937 = .3587
Minimum 9.07mm X .03937 = .3571
The 1904 DWM Catalogue I have states the diameter of the 9mm projectile at 9.02mm, or .3551 inches.
In the US, we typically quote a bullet size by its diameter, (i.e. .357).
Conclusion:
The original DWM spec. bullets were made .002 inches smaller than the barrel's minimum allowable groove diameter and .003 smaller than its maximum allowable diameter.
The question is why was this done?
Sieger
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