Some better, some worse. They were manufactured by the Austrian Army's Vienna Arsenal and by a variety of Austrian contractors, and it depends on who manufactured them and which importers handled them. Some of the arms sold to the Federal Army by Böker and Company, for example, are described in the company's internal correspondence as "seconds." Compounding the problem, the Federal Army's inspection process for all arms in Europe in 1861-2 was utterly incompetent, and wasn't much better at the New York Ordnance Agency, through which all of the Federal Army's foreign arms purchases passed. The Ordnance Office assigned one inspector to go to Europe to inspect all of Böker and Company's 186,000 arms, and I strongly suspect that he was on the take. As a counterpoint, the British legation in Brussels reported that some Liege manufactured Enfield barrels were being shipped to England for manufacture into Enfield rifle muskets without proof as "gas pipes."
Paragraph 1426 of the 1863 version of the Revised United States Army Regulations required unit commanders to submit bi-monthly damaged arms reports. Occasionally an army does something bright, because the stated purpose of the requirement was to permit the compilation of the reports into instructions to the Federal armories to “correct defects in the manufacture” of arms. The National Archives has preserved a small file of these reports. A large percentage of the reports for all weapons in service dealt with broken or mashed nipples; broken or weak springs, particularly main springs; broken hammers; broken screws; and burst barrels. The problems were universal, with the majority of the reports involving Springfield, British, “French,” and Belgian manufactured arms. Despite all the whining in the field, there were only six reports related to Austrian arms in the file. Most of the problems for all of the weapons involved failures in metallurgy on the part of the manufacturers.
When the Ordnance Office sent qualified ordnance officers out to inspect regiments' Austrian arms following complaints from the field the inspectors generally found the problems were related to abject maintenance failures by the troops and corresponding leadership failures by their officers. Why on earth would you want to clean the things?
Here is a short answer to stay within the limits of an internet forum post. The Austrian M-1854 rifle (which we now call the Lorenz) was one of the most widely used infantry arms by both sides in the US Civil War. Some soldiers complained about them and no doubt there were issues, perhaps due to having been used elsewhere in Europe before being sold as surplus by the Austrian government. Another issue was incorrect type ammunition issued to soldiers. Additionally, the sights were not calibrated in yards, but the Austrian equivalent called "a schritt" (roughly one step). The correct ammunition as well as the officer's manual (Osterrichische Infantrrie-Feurgewher, Wien, 1857 ) would have explained these things but were not included along with the weapon. Later, at least according to the McRae Papers, there are several CS purchases from the well known English ammunition manufacturer Eley Brothers that include quantities of Austrian ammunition. One such invoice for 600,000 Austrian Rifle cartridges is dated July 18, 1863. While some later contract arms were produced or re-bored in the US standard .58 caliber, the original design was 13.9 mm which is roughly .547. It seems likely that some of the period reports that describe the Austrian M-1854 rifle as “inaccurate” are due to using the wrong sized ammunition.
For these reasons (and others) there were complaints about their quality and serviceability. Others were very pleased with their Austrian rifles, Leander Stillwell of the 61st Illinois wrote in "Story of a Common Soldier" that his Austrian rifle was a "wicked good shooter." The earlier model 1842 large bore tubelocks converted to percussion cap were not as well thought of.
I think our resident expert Don Dixon, covered other relevant information in the previous post, too.
I bought an Austrian piece many years ago. Converted to percussion and rifled. I honestly do not recall what Model/Pattern it was. Like any piece I acquire I completely disassembled it (I didn't remove the breech plug) and inspected every part. I didn't see anything wrong or condemning. Screws and other parts well made. Threads were COARSE AND BIG. No cracks or flaws. Springs were well formed and strong. I don't recall a lot of tool marks or scratches. Numbers and stampings were readable but were not recently done. The wood was not inlet too deep or crude. A few age cracks but nothing major. Not sure if it was walnut but it was hard whatever it was. Using a bore light everything looked worn but still shootable. No chatter marks or scratching from the tools. There was pitting around the nipple area but that comes from bp and cap corrosion. Overall it appeared to be well made and entirely suitable for use. I DID NOT SHOOT IT. A collector friend bought it right off. Too bad as I wanted to put it through its paces and find a bayonet for it. Like others have said there were good ones and junkers.
The Museum of Military History in Vienna is well worth a visit. They have a wide variety of firearms on display. I did a tour of it a few years ago, the city itself is amazing the architecture is stunning.