5.7x28

What do we know about this cartridge? Can I get a conversion unit for my sr1911?

It looks interesting. 8)

It's a somewhat hot-rodded .22 centerfire originally intended to penetrate body armor. There are very few pistols chambered for it and, AFAIK, no one makes a 1911 conversion to fire it.

Rock Island Armory sells a similar hot .22 centerfire called the .22 TCM and a 1911 designed to fire it.

I shot a bull pup designed gun in that caliber at last years East Coast Rugerfest. Thanks Ashley! It was a HOOT! Very little recoil, and did I mention accurate?
gramps

Is it a SAAMI recognized cartridge? I don't see anything on the SAAMI web site about it. I was wondering about pressure and chamber/cartridge dimensions. 8)

I believe FN developed it, and makes the guns chambered for it.
https://en.m.wikipedia.org/wiki/FN_5.7×28mm
gramps

Developed for by FN for the FiveSeven. high velocity .22 centerfire. It caught the media's eye because it was capable of penetrating some ballistic vests (bullet proof don't exist). Thus it became a "cop killer" think one of the last Lethal Weapon movies in which more 5.7 ammo was stolen from the evidence locker of the LAPD than had been imported up to that point.

It is an effective anti personnel round that has very manageable recoil. It works very well in Personal Defense Weapon type firearms. But those in and of themselves really never caught on in a bit way.

I've fired quite a few rounds and it is fun, but not any better than a good old .45 acp when push comes to shove.

Full auto FN P90's in 5.7x28 featured prominently in the later seasons of Stargate SG1.

Seems I remember a 5.7x28 upper for AR15s as well.