M-design core barrel

M-design core barrel

[′em di‚zīn ′kȯr ‚bar·əl]
(design engineering)
A double-tube core barrel in which a 2½°-taper core lifter is carried inside a short tubular sleeve coupled to the bottom end of the inner tube, and the sleeve extends downward inside the bit shank to within a very short distance behind the face of the core bit.