Family #74 in the 1775 Grimm census.
Georg Karl Rudolph was born into a German family who immigrated to Russia in 1766. He is not listed in the Kulberg Reports, the immigration record that lists all Germans who immigrated to Russia. His family's entry in that record names only two children: Johann (Johann Konrad) and Catharina. It's possible that his name was inadvertently omitted from the record, but that can't be proven. Finding a copy of his German birth record would establish his birth year, but a search of online records thus far has not found any possible matches.
The confusion is established in the 1775 Grimm census. It lists Georg Karl Rudolph age as 18, giving him a birth year of 1757. If this is correct, then he should have appeared in the Kulberg Reports with the rest of his family members. He would have been 9 years old in 1766. If he was in fact 18 years old, he would have been the oldest "child" in the family. Georg Karl Rudolph is not found in the entry with his family in the Kulberg Reports.
In the 1775 and 1798 Grimm censuses, the children were divided between males and females. Within those categories, they were listed from oldest, the first name, to youngest, the last name. Instead of being listed as the first child of Balthasar and Eva Bechtold, he is listed second, despite being, at 18, the oldest child in the family. This is so unusual that it suggests an error, either in the positioning of his name, or in the age listed for him.
It's possible, however, that there was a transcription or typographic error with the age reported for him in the 1775 census, and he was only 8 years old, instead of 18. If this is true, then he would not have been listed in the Kulberg Reports because he wasn't born yet, and the names of the male children in the 1775 census wouldn't be out of age order, oldest to youngest.
The 1775 Grimm census also reveals that sister Catharina was not father Balthasar Rudolph's daughter. Instead, she was his step-daughter, the product of Eva Bechtold and her first husband, a Mr. Lusmar. In 1775, Catharina was 16 years old and Georg Karl was either 18 or 8.
If Georg Karl was 18, then Eva Bechtold Rudolph could not be his mother, as she would have married Balthasar sometime after her daughter's birth, which occurred two years after Georg Karl's birth. This also indicates that his father Balthasar was married at least once before he married Eva Bechtold, and that first union produced Georg Karl, and possibly his brother Johann Konrad. There is a gap of 9 years between brothers Johann Konrad and Georg Heinrich. Additionally, the two youngest children were born in 1770 and 1772, when Balthasar was clearly married to Eva, so there is no question about who their mother was.
If Georg Karl was only 8 in 1775, then he was born in 1767, one year after his family immigrated to Russia. Ergo, his name wasn't missing from the Kulberg Reports. This also means that Eva Bechtold was his mother, and that the male children in the 1775 census are in correct birth order. The only problem was a typo in his age, which should have been 8 instead of 18. This eliminates the large gap between the three youngest children, all the biological children of Eva Bechtold.
If Georg Karl was born in 1757 and was 18 in 1775, then:
If Georg Karl was born in 1767 and was 8 in 1775, then:
The confirmation of the age/birth year of Georg Karl affects more than just him. It seems so much tidier to give all the children the same mother. The reality is, however, that possible errors in the only sources available for early Volga Germans could mean different mothers for two of the children, and thus different maternal ancestral lines for the children.
1775 Grimm Census 
Georg Karl's name is not in the 1798 Grimm census. He may have married and moved to another village and was inadvertently omitted from the appendix section of the census that lists those who moved away. It's also possible that he was deceased. A search of 1798 Census of the German Colonies along the Volga, Volumes 1 & 2 shows that Georg Karl Rudolph did not appear in any census listing in the upper Volga German colonies.  This fact tends to support the premise that Georg Karl passed away before 1798, probably in Grimm.
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