I remember selling those Mark X’s back in the late 70’s/ early 80’s!
In the early 2000's, I lived just a couple blocks from the old Interarms Alexandria warehouse on the Potomic River. The business had shut down by then, but the warehouse still stood and appeared mostly empty and unused. I walked past the building a few times before I realized what it was. I wouldn't be surprised if there were still a few old gun crates, now holding only dust, kicking around in there. I even used the gunsmith that was in that building at that time. Not sure if that gunsmith ever had any connection to the Interarms business, but I bet he did.
While there were other sexier rifles on the market, I think the Mark X rifles were really good for what they were, and were a very good deal. My pictured Mark X Full Stock model is a very well made controlled round feed rifle. Nothing fancy, just a very good design that is well made at a very fair price.
The gun designer Ferdinand Mannlicher working through Steyr-Mannlicher and, later, with Otto Shoenaur, made the full stock style popular, and thus such stocks are sometimes generically referred to as "Mannlichers", much the same that blue jeans are sometimes called "Levis." Mannlicher's primary contributions to rifle technology were new breeching and magazine designs. Such design are now obsolete, but, and, despite not inventing it, the full stock pattern remains associated with his name to this day. If you do a search on Gunbroker with the term "full stock", you will get hardly any hits on such rifles. If you do a search with "mannlicher" you will get a 100's of hits showing full stock rifles of many brands, with the most common being the well-regarded Mannlicher-Shoenaur rifle with full stock.
https://en.wikipedia.org/wiki/Ferdinand_Mannlicher
