There were three models of Extra Corps weapons at the time of the American Civil War:
Muster 1844 Extra Corps Carbines: This piece was originally developed by the Austrians as a device for converting arms which were not suitable for conversion to Muster 1842 tubelock muskets from flintlock. These Extra Corps carbines were manufactured as smoothbores in .693 caliber with a barrel 33 inches long. On 2 December 1861 Major P.V. Hagner, U.S. Army, New York Ordnance Office, wrote about the arms delivered by Böker and Company: "Mixed with the barrels of usual length are many short barrels, thirty-three inches long. Such guns are of little or no value, and ought not to be imported." Major Hagner was singularly clueless - even through he was the Chief of Ordnance after the Civil War - and apparently did not realize what the Austrian used these weapons for. In December 1861 500 Extra Corps weapons were issued to the 86th New York Infantry. In 1862 the State of New York returned 1,418 M1844 Extra Corps rifled muskets in .69 caliber to the Federal Ordnance Department. So, rifled Muster 1844 Extra Corps weapons were issued and used in the Civil War, and it is possible to document some unit issues.
Muster 1854 Extra Corps Carbines: Major Caleb Huse, CSA, purchased at least eight batteries of Austrian artillery, which he and S. Isaac Campbell and Company repeatedly characterized as "complete" in invoices and correspondence. Included in the TO&E for each battery in Austrian service were 16 Extra Corps carbines which were used for guard duty. On the march, they were carried in one of the battery wagons. So, Huse's purchase, if the batteries were in fact complete, should have included 128 Muster 1854 Extra Corps carbines. I haven't found an invoice specifically stating that the Extra Corps carbines were, in fact, supplied with the artillery batteries, or documentation that they were successfully run through the blockade.
Muster 1862 Extra Corps Carbines: The Austro-Hungarian Army was selling Muster 1854 rifles, Jägerstutzen, and Dornstutzen to the Federals and Confederates to fund its rearmament with the Muster 1862 version of System Lorenz arms. I had thought that it was unlikely under these circumstances that they would have sold any Muster 1862 arms to either side in the American Civil War in any quantity. I know definitely of only three Muster 1862 infantry rifles which were sold to the Federals. They were procured for foreign materiel exploitation, and they were expended - blown up - in testing.
However, there are repeated references in original sources to "short" Austrian rifles. These reference do not appear to be compatible with Muster 1854 Jägerstutzen or Dornstutzen. And, they have no specifics regarding models of weapons.
I have two Extra Corps carbines purchased on this side of the Atlantic: a Muster 1854 and a Muster 1862, with Type I sights. Both are original and well worn. I strongly suspect that small numbers of Muster 1854 Extra Corps carbines were imported, and perhaps Muster 1862s, but proving it has been impossible to date.
Regards,
Don Dixon