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I've got Pejsa's little red book and it's definitely his formula - at least the construction of it. Strictly speaking, above 1400fps and using the US .30cal M2 bullet as its reference projectile, it breaks down to:
r = 332 (sqrt(MV) - sqrt(V1))
...which rearranges to:
sqrt(V1) = sqrt (MV) - r/332
...with r in FEET.
If you do R in yards and change the fraction into a decimal, you do actually get sqrt (V1) = sqrt (MV) - 0.00904 R. Now the BC doesn't actually figure in this at all, at least if you use the M2 shape without modification. Dividing 0.00904 by 0.00863 gives about 1.047 (the reciprocal is about 0.955), which makes me wonder if there hasn't been some sort of correction for form factor put in, to relate the M2 projectile back to the typically-published G1 coefficients. I honestly don't know.
I recall that the formulae were given in the magazine article "as is", with none of the attempts at derivation which Pejsa gives in his book. That makes me more certain that this IS Pejsa's formula as above, but presented for ease of use by everyday hunters and target shooters who want to just plug in the numbers they know (range, MV, BC) and get out an answer they can then insert into further calculations (deriving K, F, etc. and using them to plug into the drop, TOF and other equations; in effect, going the other direction from the line Pejsa's book takes).
This is looking more and more likely the more I consider it.
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