Yes, been around the block, why "true"? Seems like a strange and misleading term...would be a true 7.2 mm bullet, to me, at least
Deleted member 1487
The caliber is always determined by the barrel diameter not the bullet diameter. They use a larger bullet so seal the gas behind it and to force it into the rifling to impart spin; if they were the same size the gas would pass over the bullet through the rifling and the bullet wouldn't engage with the rifling properly.
The 'true' part might be in reference to similar calibers that round up when stating their diameter.
Considering that the article was from American Rifleman, they are probably saying that .276 Pedersen was a true 7 mm caliber cartridge compared to .270 Winchester and .270 Weatherby Magnum, which have 7 mm bullets fired out of 6.8 mm barrels.
not always, e.g. .30-06 uses the bore diameter, and .308 win uses the bullet diameter
there's a lot of weird when it comes to cartridge designations
e.g.
7.62x54r and 7.62x39 have a bullet of .311"
.30-06, .308/7.62x51, and other us ".30 cal" rounds use a .308" bullet
7.5x54 french uses a .308" bullet
7.5x55 swiss uses a .306" bullet
Caliber is always bore diameter. Some US cartridges have used bullet diameter as part of a trade name or brand name to differentiate themselves from similar cartridges made by competitors. The .308 Winchester was named so it wouldn't be confused with the .300 Savage cartridge it was based on.
Try a 7.65 x 53 Argentine. I had a butchered one once. Someone had rechambered for 30-06. Bullet diameter is about 7.9 mm. Nothing worked so I had it rebooted and chambered fo .35 Whalen. It was quite accurate but decided was not into hunting and sold it
Deleted member 1487
Yeah I saw that this morning, pretty informative and debunks some myths about why the US MG42 clone failed and wasn't pursued further after the war. If it were in 7mm 'short' then perhaps something might have been done with it post-war. Of course there was the small issue of the ROF the US did not like about it.
As an aside it was interesting the Finns got a rimmed 7.62x54 version to work well; a Soviet post-war version would have been interesting, especially a 7.62x39 version. In fact I'm kind of surprised no one did given that even the Spanish made a 5.56mm version of the MG45.
Deleted member 1487
Since there was already the RPD in 7.62x39 and the Taden gun in .280 British something like that should have been a decent weapon if in MG42 layout. The MG45 would probably have been the better version of it, as that was substantially cheaper and lighter than the MG42 IOTL.
Now if it were in 6mm...