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I have seen PLA videos of basically an urban combat live fire on static targets.
You get an absurd amount of keyholing at ranges that between 5 to 10 to 20 meters.
Its possible this particular image is from a longer distance static range, but the keyholing problem seems to be quite widespread, irrespective of range.
As has already been said, something is going seriously wrong with either the guns, bullets or both that are being mass produced for around a year now.
https://www2.kenyon.edu/Depts/Math/Paquin/GeomSeriesCalcB.pdf
Here’s a standard introduction to the concept of the Convergence/Divergence Theorem of Geometric Series, starts on page 2.
Its quite common for this to be referred to as the convergence test or rule or theorem by teachers and TA’s.