HELP ID - WWI HQ Artillery rank insignia patch

[Spudboy]

Any assistance would be appreciated - A little context:

 

I am building a shadow box of my wife's grandfather.  I have his service record, medals and collar tabs as pictured.  What I am struggling with is the rank insignia that I acquired at auction.  

 

His service record indicates states that he was inducted  Dec 19, 1917 - discharged Feb 8, 1919.  Highest rank attained Corporal.  He was assigned to artillery HQ and family history has him as a runner.  Service record indicates he was assigned to Artillery "CAC?" then to the AEF.

 

 Question - Is this the correct Rank Insignia patch for his service?   Any hep is greatly appreciated.  Thank you.

 

[Salvage Sailor]

CAC is the Coast Artillery Corps  -->> Insignia of the Coast Artillery Corps

 

[Spudboy]

thank you - Pardon my ignorance - Is the HQ collar disc accurate due to being part of the AEF?  any help on the shoulder patch would be appreciated

 

[Tolzer]

Here a a few examples for a CAC Collar Disk that would meet your time period.

 

Reference:

The Collar Disk Story (1907-1999), L. Albert Scipio II

[atb]

The disk is for the headquarters battery of a field artillery unit so it could work for his AEF assignment. More thZn likely he wore a plain corporal chevron with no gunners device.

[Spudboy]

Thank you sooo much.  I appreciate your expertise.

[atb]

On 12/17/2025 at 12:13 PM, Spudboy said:

Any assistance would be appreciated - A little context:

 

I am building a shadow box of my wife's grandfather.  I have his service record, medals and collar tabs as pictured.  What I am struggling with is the rank insignia that I acquired at auction.  

 

His service record indicates states that he was inducted  Dec 19, 1917 - discharged Feb 8, 1919.  Highest rank attained Corporal.  He was assigned to artillery HQ and family history has him as a runner.  Service record indicates he was assigned to Artillery "CAC?" then to the AEF.

 

 Question - Is this the correct Rank Insignia patch for his service?   Any hep is greatly appreciated.  Thank you.

 

The chevron looks like a pre-WW1 cotton service uniform example for a corporal holding a gunner's rating.

[CAC1901]

He would have worn a standard olive drab wool corporal chevron on the right sleeve. These are easy to get and fairly inexpensive. The particular chevron you have is ca. 1904-1908 era first class gunner / corporal brown duck chevron for the brown duck fatigue clothing worn at coastal gun batteries well before WW1.  Much of the 'coast artillery' of WW1 like your wifes grand dad were initially assigned to coast artillery units but did not operate in the usual coast artillery mode. They were distributed to the AEF in France, for example the First Army, and basically operated as heavy field artillery.  

[Spudboy]

Thank you soooo much.  Your narrative seems to fit very nicely with his service record.  Thank you again - I really appreciate it!!!!