A very interesting cartridge.
I've only got to shoot one gun in the cartridge. A Kel-Tek P50. I have a friend getting on in years and he's starting to acquire 'unusual' guns and in my opinion this sure is one of them.
https://www.keltecweapons.com/firearm/pistols/p50/It was fun to shoot, little recoil, which the Kel-Tek absorbed nicely and the gun seem accurate enough although we shot standing. I'd really like to have some support to see what it could really do.
Loading the magazines for the P50 was just totally the pits. A problem you won't have if you go with the Ruger offering.
5.7x28 ammo can be found for $25-$35 per box of 50 if you check around.
https://palmettostatearmory.com/fiocchi ... fmj40.htmlReloading the 5.7x28 is a little quirky I've heard.
https://www.handloadermagazine.com/hand ... n-5-7x28mmGood luck. I'd be interested in what you think of the Ruger if you get it.