In 1975 I was stationed in San Diego. We had finished a cruse and I had lots of free "down time" and was working part time at a local gun shop. The owner had just returned from Mexico where that country had dissolved citizen gun rights and returned with a case of Krag rifles.
Most were in very good shape with bright bores. I got one for 75 bucks and grabbed a hand full of original cartridges and went to the range.
I had been collecting US military firearms for tens yeas by then and was really looking for a nice shooting rifle.
I loaded up the rifle and pulled the trigger. The bullet missed the target by several yards and I noticed "silver confetti' fluttering to the ground. What the heck?
I removed the cartridge which looked fine and the bolt. The rifling was gone! As in blown out of the barrel. The Mexican military had fired mercury primed ammo out of the rifle and never really cleaned them before putting them in storage. The rifling had amalgamated and had become soft/brittle over the decades.
I told the owner what had happened to the rifle and he checked the others as well. Some were worse,others were a little better.
I got 25 bucks back as I wanted to keep the rifle as a type in my collection. I'd find a new barrel and replace it.
That took 40 years! All I ever found was Bubba'd barrels or the wrong year type barrel. I wanted to find an original barrel.
In 2016 I did. It was like new on the inside with a nice patina on the outside that matched the rest of the rifle and it was the same year! Wahoo.
I had my local gunsmith mount the barrel. I went to the range and with 220 grain RNFB FMJ's the rifle shot very well at 100 yards. I set my target to 500 yards and had no problem using the peep sight and hitting the target. The rifle has shot very well at 800 yards as well.
But, there is a problem. The chamber is long. Head space is within "field" but the fired cases stretch in front of the web. They fail if reloaded. Crap. Oh well.

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