Is CCI Stingers worth the extra cash over the Federal Hypervelocitys?
No. If a person would run the Stinger over a chronograph, they would see that they are not 1640 fps either. The Federal 31gr does run as advertised. However, if the situation truly is:
It's mostly target shooting only for me.
Then, the OP is going in the wrong direction. The mini mags or AR Tactical are going to group better than any hypervelocity cartridge.
But more importantly, CCI does not make accurate ammo in the big scheme of things. They make ammo that is better than total garbage. We may pump our fists that we bought American, when we may have been able to pay similar cost for better 22LR ammo. If you're looking for accuracy, the longkept non-secret is that even the cheapest ammo made by the European manufacturers - Eley (Wolf), Lapua (SK), or RWS (Geco, Norma, Prime) regularly outperforms our beloved; never tarnished image; how dare you say that about - CCI.
Sure, someone is going to post their three shot group from 35 yards that is one hole, or some other such statistical travesty with CCI SV. I don't doubt that they may have shot such a group. However, they may never say how many groups they had to shoot to get that one group - remember, statistical travesty.
So, is the cheapest Euro ammo the best ever? - no. I'm just saying that, on average, it is better than CCI. The likes of Tenex, R-50, and X-act/Midas are expensive for a reason. That reason is they are incredibly consistent.
It has long been known that a 40gr bullet at 1080fps will on average get the best accuracy from a 1/16 twist 22LR. It helps to have that lube that sticks to your fingers that people complain about. It helps to have bullets that aren't all dinged up and have consistent bases (which you cannot see once seated, btw). It helps to have consistent priming, charge weights, and consistent exit velocities.
However, when many shoot that in their sloppy, inaccurate, semi-auto 22LR, it short strokes. And that is why people rave about the "function" of CCI because it will cycle. They leave out that Euro manufacturers now make a semi-auto version that is 1150-1200 fps that both cycles their semi-auto AND typically attains better accuracy.
So here's the challenge. Buy one box of 50 round of the cheapest European ammo that you can find from the brands above and visually compare the cartridges to whatever CCI/Fed/Rem/Aguila/Win that you are shooting now. Visually inspect the consistencies of the bullet, the crimp, if the bullet is canted, or can spin. Then, if you have the means, run both the 50 Euro cartridges and any 50 American cartridges over a chronograph. Then compare the velocity statistics and the target groups.
What you will find is that it is not a brand that your 22LR likes, it's quality that it likes. Consistent components and consistent exit velocities lead to smaller groups.