Originally Posted by
goatbrother
The popularity has wained. For a couple reasons. They are a mid length case that usually requires them to be chambered in a long action gun. If buying a long action why not go for a case that has more capacity and thus better performance. A 25-06 over a 257 Roberts, or a 280 Remington over a 7x57 Mauser. Add to that the newer cartridges like the 260 Remington that duplicates the 6.5x55 or the 7mm-08 that duplicates the 7x57 but in a short action rifle. Factory loadings that are kept to lower presures due to older weaker guns also contributed, a handloader can soup them up but if you don't reload your stuck with weak loads. And of course MAGNUM MAINIA is a factor too.
This answer pretty much covers my thoughts as well. I am fascinated with the history of the 7x57 and 6.5x55 and, because I am a rifle looney, I own a couple of rifles in each caliber, two of which are custom Mausers, which I consider family heirlooms. With the excellent short action .260 and 7mm-08 rifles now available, most non-looney riflemen will opt for the relatively speaking "modern" calibers. Of course, loonies will own at least a couple of rifles in these calibers as well, and I just added a Sig in .280 because I really like the 7mm bullet offerings. Nothing like choices when it comes to rifles. The only caliber I have not yet talked myself into buying is a .257 bob. My Sako AV in .25-06 satisfies me completely so far.