My brother in law let me shot his Ruger 5.7 pistol and I really liked it 1911 size that can carry 20+ rounds. What stopped me was the price of the ammo. I reload and would just have to buy new dies for my press I have .223-.224 bullets. Yet I have not talked to anyone who has reload this round and wanted to hear thought.
Years ago i believe I heard that those had a polymer coating on the cases that was integral to the operation of the firearm. So that might require special handling/cleaning. Also, that sucker has small case capacity. the variance from a normal pressure to a kaboom round might be in the range of less than half a grain? I think the factory uses adhesive to lock the projectile in the neck where a reload you might need to crimp? Not sure. Not sure I'd want to reload that one. To each their own though.
My brother bought a FN 5.7 around 20 years ago, wanted to know if I would reload for him. All the info about reloading the 5.7 case was a major no-go. It has such a small case capacity that it has such a very small pressure window from a safe load to a high pressure load that would spontaneously disassemble your weapon along with your hand with it. I have not researched this since then, maybe something has changed since then with new propellants but that would be up to you to research on your own.
A FRT on a P90 (Garand Thumb just released a video on this) would be pretty slick. I’m interested, but doubt I could afford to feed it!
