30 Cal Rifling Twist Rate

[sheepherder]

As far as Wikipedia goes, I accept their articles with the same skepticism as I would the writing on the men's room wall at my favorite bar. Any moron can post to Wikipedia, and usually does.

I like to gather 5 or 6 articles from the Net, with visibly different sources [pics, descriptions, dimensions etc] and take an 'average' of them all for my own uses. Of course, if it is in Machinery's Handbook, then it is gospel handed down from Heaven above, and should be treated as such.

In my own experience, the land diameter of my Luger 7.65mm barrels is right at 7.65mm [.301"]. I use a 7.6mm squib rod as reinforcement for my mount/dismount procedures. The .05mm [~.002"] makes it too tight for my preference. .301" + (2 x .005") [assumed groove depth] = .311". That's kind of high, IMO, for a 30 cal bullet - I'd assume .004" groove depth, which gives .309", pretty close to what bullet mfg's quote their "30 cal" bullet size as.

The 8.82mm land diameter found on most P08 barrels works out to .347". If you assume .005" groove depth, that gives you .357"...Again, IMO, kind of high...I'd assume .004" again, which gives .355"...A common "9mm" bullet size...

Just an observation; nothing pertinent to this thread.