6.8 SPC Chamber Drawings
Below are sections of the chamber drawings of
the various 6.8 x 43 mm chambers showing the area discussed in the article.
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Original SAAMI Chamber
showing the angle error. On the drawing above, based on the dimensions specified in the
drawing the angle works out to 70° 55':. |
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Original second version SAAMI
Chamber ("SPC II") showing more generous specs
but continuing the angle error. On the drawing above the based on the dimensions specified in the
drawing the angle works out to 71° 30' *
I
have recently been informed that the SPC II reamers currently (2/09)
being cut now actually have a 45 deg angle, which would mean that the
horizontal measurements would be .105 and .0905", giving .01495" |
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DMR (Designated Marksman
Rifle) chamber showing
improved angle. If you do the
math you get an
angle of 35° 1'. Note the tighter neck (.305") and throat (.277") dimension.
There have been several variations of this drawing circulated with the
angle varying from 25 to 37 degrees. and all associated with barrels
using the 5R rifling form. |
Thanks to Tim W. for supplying the
drawings
Please email comments or questions to Fr. Frog by
clicking here.
| Back to 6.8 article |
Disclaimer
As far as I know all the information presented
above is correct and I have attempted to ensure that it is. However, I am not
responsible for any errors, omissions, or damages resulting from the use or
misuse of this information, nor for you doing something stupid with it. (Don't
you hate these disclaimers? So do I, but there are people out there who refuse
to be responsible for their own actions and who will sue anybody to make a
buck.)
Updated 2009-02-10