With a decade of fast Mini-14 sales behind them, Ruger decided to up-gun that .223 rifle to a much more impressive .308 caliber around 1984. The result was the XGI rifle and they are about as rare as it gets.
Why the XGI?
In the mid-1980s, Ruger was planning a reinvention of the company to include police and military products. They marketed the AC556, the GB-series Mini, and introduced the P-85 pistol all aimed at law enforcement sales.
Many police departments were adopting the '14 for use from coast to coast and it made sense to offer an accurate but compact semi-auto in .308 Win that could be used by SWAT teams and the like. Other 7.62x51mm options on the market for LE use at the time, the Springfield M1, HK G3, and semi-auto FN FALs, were and still are very long and awkward to use rifles tipping the scales at close to 10-pounds. That's where the XGI came in.
Stretching the Mini-14 design by just 2.65-inches, Ruger engineers came up with a .308-caliber variant that still came in at under 8-pounds overall weight and 39-inches overall length. Mechanically identical to the operation of the Mini-14, everything was beefed up to accommodate the larger round choice, which makes the gun virtually identical to its father.
Like the other Mini's of the time, it had scope bases machined integrally into the receiver, side ejection, a fold-down auxiliary adjustable aperture sight, and a blade front sight. A red butt pad affixed to a deeply stained walnut stock was standard.
In addition to LE sales, the gun was to be marketed to the hunter's market with a .243 Win offering in the works at the time. Retail was to be $425 in 1985, which, adjusted for inflation, would be about $925 in today's dollars.
1985 Ruger catalog page on the gun offering great things to come...
Ruger brought out these guns with a good bit of fanfare in their 1985 catalog as well as in industry rags of the day to include SWAT Magazine who predicted that "Barring any unforeseen hang ups in final production, by the time this appears in print the first of the XGI rifles should be on their way to dealer's shelves."
Well, about that.
It seems the gun had accuracy issues in testing and, according to the company's own notes on the subject, Bill Ruger put the project on hold indefinitely when he decided not to expend additional engineering efforts to improve the rifle's accuracy. Less than 100 (likely just .308 versions) were fully assembled and Ruger never commercially sold the gun in any form.
Getting your own
In short, don't hold your breath.
In 2010, Ruger let one of these guns go from its factory collection in Southport, Connecticut as part of a charity auction. That gun was serial numbered 800-01329 and chambered in .308 Winchester. It was rollmarked on December 12, 1984. Auction price? $5,000. According to internet searches, another had previously popped up in 2008.
Now whether or not the company still has the other 98 sitting in a corner somewhere or a few others made it out onto the market is anyone's guess.
In the end, Ruger walked further down the road and developed a 7.62x39mm version of the XGI concept in 1986, the Mini-30, and the rest is history.