Discussion on Rifling

[sheepherder]

I read this comment on another [Enfield] forum...

Well all the Lee Enfield bores I've examined had very deep rifling grooves, as would be expected since original acceptance specs call for grooves from .005 to .008 in depth. Conventional rifling of the day called for grooves .004 in depth.


http://www.surplusrifleforum.com/vie...?f=27&t=113788

To put that in perspective, a sheet of lined notebook paper is ~.003"...

'Conventional rifling' applies (I suppose) to other rifles...

Does the Luger have ~.004" deep grooves??? Let me see...

I see my Lugers barrels are marked as follows:

1 - 8.84mm [.348"]
2 - 8.81mm [.346"]
2 - unmarked commercial

Assuming a Parabellum bullet is .355", that means that the difference in diameter is .007" and .009"...which would work out to grooves .0035" and .0045" deep...

So, yes, my Lugers [as marked!] are ~.004" and would be 'conventionally rifled'...

The central point of the discussion was that a barrel can be shot/worn to the point of groove depth being only ~.002" and still be accurate, if handloaded accordingly (bullet dia selection)...

I don't have any specs here to compare...

But I would have expected a rifle barrel to have shallower grooves, due to its greater length [compared to pistols]...

Anybody like to comment???