Completely correct if the groove continues all the way around the circumference of the bullet.
With GSC bullets, once it has been engraved by the rifling, there is no groove but a series of buttons that are buried in the boundary layer of air that flows over the bullet. This does not raise a secondary shock wave and does not affect drag.
Interesting hypothesis. Experimental support?
Is velocity recorded BC testing of these GSC bullets one way to test this?
I notice the ridges (bands) on the GSC bullets are much smaller than the bands in the first bullet pictured. Also the first bullet is cut circumferential below the diameter of the lands (like Barnes bullets), whereas there are no such cuts in the GSC. This alone should improve BC value of the GSCs.
Completely correct if the groove continues all the way around the circumference of the bullet.
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With GSC bullets, once it has been engraved by the rifling, there is no groove but a series of buttons that are buried in the boundary layer of air that flows over the bullet. This does not raise a secondary shock wave and does not affect drag.
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Thank you for the informative post.
The pictures of the grooved bullets are a bit deceptive in that neither bullet shown is a Barnes bullet.
These are not the same at all. Barnes bullets are full caliber diameter with grooves. GS bullets only the groove - upset is full diameter. They are in all reality undersized.
A person could make a reasonable point that sabot round is undersized as well, but that does not make them a low performance concept. I have no idea if it would work, but it would be interesting to see what happens in a bullet that uses drive bands and has portions of it significantly undersized:
Example 375 size chambering, with the bulk of the bullet 358 or 338 size, maybe with tapering to help fill in the hole. I have no idea if the concept makes sense, but in theory you could use a 375 H&H and make it go really fast with an improved SD if it behaves like a normal sabot.