What's the original spec's on barrels???

Sieger · 04-21-2004, 06:34 PM

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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04-21-2004, 06:34 PM	#14
Sieger User Join Date: Jul 2003 Location: New York, NY Posts: 1,579 Thanks: 2,154 Thanked 402 Times in 251 Posts	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