This is excerpted from an article by John Barsness printed in the May, 2017 issue of Guns Magazine:

Before World War II the Stoeger company imported Steyr sporters, but after the war all German and Austrian arms factories were closed for several years. Stoeger filled the gap by having a number of carbines made on a military Mannlicher-Schoenauer action, commissioned in 1930 by the Greek government. A few years ago I acquired what may or may not be one of these semi-custom carbines, through a trade with a rifle loony named Scott Magie. There’s no Stoeger name on the carbine, but it’s very well done, though with a 19-inch barrel rather than the 70cm (17.7 inch) barrel on the original 1903 carbines. Scott had a local gunsmith fit a Williams aperture sight to the cocking piece, and despite the extra barrel length the carbine still weighs only slightly over 6-1/2 pounds.

It also has an essentially pristine barrel measuring the modern standard 0.256-inch across the lands and 0.264 in the grooves. Many 1903 carbines had deeper grooves, perhaps due to the cupronickel jackets commonly used on early smokeless bullets. Fouling from such jackets built up quickly to the point where some barrels bulged or even burst, exactly why the original 0.318-inch grooves of the 7.9×57 Mauser were deepened to 0.323, creating the “S” variation used in most 8mm barrels today.

Theoretically such deep-grooved 1903’s may require slightly larger-diameter bullets to shoot accurately, but my experience has been bore diameter is far more important than groove depth, the reason some tighter-bored .303 British rifles are accurate with .308 bullets. I suspect the real reason some Model 1903 6.5×54’s shoot better with slightly larger diameter bullets, such as Hornady’s 0.267-inch 160-grain roundnose, is bores were enlarged by corrosive primers, which weren’t phased out until non-corrosive priming became common in the 1920’s.

The 0.267 bullet, by the way, isn’t listed at this instant (8:48 a.m. on December 26, 2016) on the list of InterLock bullets on Hornady’s website, despite being specifically mentioned in their 9th manual, though if you use the “Bullet Search” function it shows up. But these days bullets come and go on Hornady’s website, depending on whether they’re in production at the time. A couple of years ago many 6.5×54 handloaders panicked when the 0.264 diameter 160-grain roundnose disappeared from the site, but it’s there now.

Scott Magie had worked up a load with the 0.264 160-grain Hornady and H4831 that got almost 2,200 fps and to save time I used the same load for hunting that fall, but found the bullet’s performance on game erratic at this velocity. Once it broke both shoulders of a whitetail doe and exited, but on another deer did not reach the far side of the chest on a broadside rib shot. Dropping the powder charge to 37.0 grains reduced muzzle velocity to a little over 2,000 fps, where the bullet has performed more reliably.

At higher velocities the 156-grain Norma Oryx, a bonded bullet, penetrates and expands very well at iron-sight ranges. The only minor problem is the squarish edge on the flattened tip which needs to be filed slightly round to feed reliably. The 140-grain Nosler Partition also shoots reasonably well and the Partition’s soft front cores expand well at moderate velocities.

However, another Hornady bullet performs well at higher velocities—the 129-grain Spire Point and it shoots more accurately at around 2,500 fps. In fact it’s the most accurate bullet I’ve found in the carbine, somewhat surprising considering the long chamber throat and it feeds fine from the magazine.

New 6.5×54 brass is no problem. I got some Norma cases in the trade for the rifle and purchased more later. Prvi Partisan brass is also available in the US. If any handloader has a yearning to use the most popular 6.5mm cartridge of a century ago, the only real problem is buying a Mannlicher-Schoenauer carbine. They’re not unknown in North America, but tend to cost a little more than the average factory rifle!

Here's a link to the whole article: Guns Magazine May 2017 6.5X54 MS