Firstly, sounds like a “9mmFN” ( aka .35Rem Auto), cartridge for the FN made European version fof John Browning’s Model 8 Rifle.
The German Proof marking. It is not the Charge weight that is mentioned in the St.m.G. (Stahl Mantel Geschoss= Steel Jacketed Bullet) but the Bullet weight. Thus your reading should be 15 Grams (not 1,5 grams) Ie ,231.45 grains, which is just right for a “9mm” Rifle Bullet.
The Barrel dimensions (Lands/Bore of .350 (8,8mm) is correct for a “9-9,3” Bullet Diameter (.354"-.366").
As to Cartridge Length, a chamber cast is easy IF the case is rimmed (ie, by overflowing the casting, into the Breech face of the Barrel, one can add up the Free body length plus the depth of the rim recess in the barrel(if there is one).
For rimless cases, one must allow for the space between the Bolt Face and the Back of the barrel (unless it is one of those “completely enclosed Head Designs” (like an Arisaka, but it is semi-rimmed in any case, so there is no Head protrusion. This could account for the “shorter length of the case (so called.)”.
I have not read the article concerned, but I am a subscriber to both “Rifle” and “Handloader” ( Wolfe Publishing) and I do have some Bound volumes of the earlier Editions. I will have to check whether I have it or must “back number” it, or Get the CD.
Since it was mentioned that the Author of the article made several errors, this may be another one or two. One must have a thorough knowledge of German Proofing systems and eras before making such statements. I have been caught out often enough in the Military field for NOT RESEARCHING ENOUGH.
MY Opinion, for what it is worth, is that the rifle was originally Chambered for 9mm FN (aka .35 Remington Auto, the most common Auto rifle cartridge available in Europe to Hunters etc before WW I (along with the 6,35 (.25 Rem Auto) the 7,6 (.30 Rem Auto) and the 8mm (.32 Rem Auto) which were distributed for Remington by FN (FN seems to have only made the “9mmFN” under their Patent Arrangements with JMB.).
Too bad that this rifle-Cartridge combination was not further developed in WWI…would have made an excellent" Sturm- Gewehr" for Trench Raids ( the Winchester Autos and Remington Autos, especially the .351/35 and .401) were used by Balloonists and early Pilots/Observers; after reliable MGs were adopted for air use, they were reverted to “Train” use by the French (Supply columns).
Ribeyrolle ( of the firm of Gladiator–CSRG) did develop a .351 Win case necked down to 8mm Balle D, and developed a Light “Fusil-Mitraillieur d’Assaut”; but the end of the war terminated all work on this interesting cartridge and gun.
Back before WW I, there were not US Modern-Style Wildcatters, even with German cartridges, either in the Continent or in the USA. Wildcatting came ito its own in the Late 1920s, with the well known cartridge and rifle designers, and of course became more commonplace after WW II. I will have to google “.35 Indiana” to find out what exactly it is.
Addendum: Researched Municion.org, and found “9x48” Browning aka .35 Remington. Case design shows a 12mm difference in Purported Chamber casting measurements (36mm) from that of the 9x48 (actually 48.6…also called the 9x49).
.35 Indiana : Indiana Legal length cartridge of 1.800" Case length for deer use…48mm is 1.890 inches, and 1.800 inches is 45,7 mm case length, and 36mm is 1.42 inches.
So therefore, since only the ammo has to have the neck shortened (not the shoulder moved) and only by about 3mm (less than 1/8") I think the Measurement of the casting was “stuffed up” (SNAFU).
The Haenel Rifle was definitely in .35 Rem (aka 9x48 Browning Brevette Depose’ aka 9mmFN).