I've only seen one period 10g pressure report; from DuPont Brandywine Experimental Station data cited by Charles Askins in 1933
DuPont Bulk Smokeless Powder (not Oval used for the Super-X loads).
10g 4 1/4 Dr. Eq. 1 3/8 oz. shot = 10,662 psi + 10-14% for modern piezo transducer numbers

And have a single 10g measurement; a Smith hammer gun with Twist barrels
Bore .798"
End of chamber L .174" and R .167"
9" from breech L .095" and R .092"
9" from muzzle L .052" and R .050"

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