Any one know why the 7x64 is not a popular caliber
I think it once was, in most of europe actually, just like the 7x57 once was too. Even today i think it is a fairly common cartridge to see in gun shops, or on the ammo shelves or with hunters in central and eastern europe, and in germany too. When i lived in Italy it was not uncommon either.
In the states, or markets dominated by the US, the 270 and 280 as well as the 30-06, probably was the choice of most hunters, looking to pretty much do what the 7x64 can do, so making a break through there was probably tough for the x64. Being german post two lost world wars probably didnt help much either.
Now Why it then lost popularity in the parts where it was once popular i think is a very good question, but besides better marketing and the general dominance of american made cartridges in the last maybe 30-40 years, even in europe, i dont know.
Personally i am in the exact same position as Heym, - i have a 7x57, and at the distances i hunt i dont need the extra power and recoil of the x64.
But if i was to buy a kipplauf and shoot in enviroments where longer shots wouldnt be uncommon then the 7x64 ,or its rimmed cousin, the 7x65r would likely be my choice. And if i could only have one hunting rifle for all european game and hunting enviroments it likely would too. Well that or the 7x57.
Between the 7x64 and 7x57 two i guess It depends largely on if one thinks the trade off of a litte more reach and power is worth the extra recoil and powder consumption.
But with range finders now being in existence, the worth of those 20-30 meters extra of flat trajectory for what most would probably consider a fair bit more recoil is probably less than what it used to be. Then again the increased KO power might be worth the rest of it, but someone like
@Heym SR20 might have more in field experience and ability to evaluate that than me tbh.