Would you settle for an uninformed opinion?
I don’t see the purpose of a rifle caliber between .22LR (1887) and .223 (1964) or between .223 and the various .30 cal (1891) variants.
I don’t see the purpose of a pistol caliber between 22LR and 9 mm or .38 caliber, or between those and .45 ACP or .45 Colt (1873).
I don’t experiment with fad calibers - if they haven’t been around at least 50 years, usually 100+ years, it’s too soon to be worth investing.
Lower recoil flatter trajectory than the 7.62x39 but energy delivered is similar.
So your saying the .270 is a fad caliber? ??