6.5 x .308 marking on a barrel? Huh?

[matt2032]

Looking at a "modified" Schultz and Larsen M54 re-barreled with S&L barrel marked 6.5 x .308. Its on Gunbroker today, (12/3/2025). Anyone have a clue to this Frankenstein? One-off wildcat? S&L short-run? Plenty of other gunsmithing questions - including the barrel markings where it meets the receiver. And WHO added "system" to the Schultz and Larsen stamp?

 

[okie]

thats just a .260 id bet...
cast the chamber, check and make sure not tight necked, check headspace with .260 gauges

 

[Doug Beach]

It’s a .260, possibly with a slightly different maximum case length.

 

[Walt Krafft]

The 6.5-08 was a very common match rifle cartridge before Remington standardized it as the 260.

 

[Will Henry]

Probably pre-260. If I had to guess (and I do), I would say the barrel was a 6.5x55 which was set back and rechambered. As for the "System Shultz & Larsen", that may be original. I remember seeing that on another M54, a little over sixty years ago. WH

 

[SBS]

WH has it right. No doubt about the barrel being set back (see stamping on pic #8), and notice see how the barrel contour does not fit the barrel channel most of the way down. 6.5x55 would be the only 6.5 it was originally and number of them came into the US back when they were made. The ones I saw were mostly 6.5x55 with long barrels. I had one of these free rifles about 30-35 years ago in 6.5x55 and it had a 30" barrel, 1" at the muzzle -- heavy dude, but shot very well. Probably a nice rifle if rifling is still good and the smith did a good job of rechambering.