I think my biggest gripe with the round being listed is that it's saying that a 60 year old cartridge IRL, 120 years old in SR, is still the current favorite. In US military circles the argument right now is whether to keep two rifle ammunition types (those with ARs/5.56 & DMRs and light machine gunners/7.62) for man portable weapons, barring snipers, or go one caliber to rule them all. There are more accurate and damaging cartridges in use IRL that weight less than the 7.62.
On top of that we're now talking caseless ammo that wouldn't use the same moniker as cased ammo, since cased ammo uses identifiers that aren't necessarily referring to caliber, but more so to formula and length (e.g. any .35 caliber round: 9mm PA & 9mm FEDERAL & 9mm MAKROV & 9mm DILLON; or .30 caliber round: .308 series & 7.62x39 & 7.62x51 & 7.62x54R & .30-06; or .40 caliber: .40 S&W & 10mm; or .45 caliber: .45 ACP & .45 LC; it gets even crazier when you get into the .28 caliber/7mm rounds).
Maybe after first inducting caseless ammo conversion kits would be requested and obnoxious amounts caseless varieties would exist (only if there was a market for it), but the reality of it would be that it's a new round and if it proved itself everybody would want a new firearm chambered in it. My example would be the 1800's muzzle loading conversion to cased ammo, there was only a few calibers at that point because having cased ammo simplified the process of making the weapons and not everybody was making ammo. Fast forward ~150 years to when caseless was made wide spread and manufacturing and engineering isn't the problem, the issue would be different rounds to do the needed things and the first company that mastered and marketed the formula would set the caliber standards, I'm assuming Ares. SR listed them as the different firearm classification (e.g. holdout, light pistol, heavy pistol, etc) and arguably many of these classifications are the same caliber round, realistically they'd probably market the rounds as the classification. I think the fluff text would have been better off saying 7.62 CR (caseless rifle) or even 7.62 Ares (or whichever company pwned the market with it).
I'm just grumpy because of the ancient label on something so far in the future that I highly doubt something that is largely considered dated, but not ineffective now, would be the standard 60 years from now...