When I was shooting ISU Pistol, Rapid Fire was one of the Olympic and World Cup events. My "Rapid" gun is a Pardini, has a 1/2 lb trigger, and (get this) is ported to reduce muzzle jump....
One of the large wholesalers imported Russian 22 Short Target ammo and sold it fairly cheap by the 7000 round, wooden case. The ammo had a larger (and greasy) lead bullet which caused some trouble in the Pardini Chamber. I put together a non ported and standard chambered barrel and shot quite a few of them through the gun. The velocity was about the same as CCI CB SHorts and accuracy outstanding.
HOWEVER.... About the same time the Marlin 39 Century featured in the Skinner Sight Banner here in MO and at
www.skinnersights.com came to our home. We started shooting those shorts in the 39 and loved them. It feeds almost flawlessly, there is no recoil or noise, and the accuracy is outstanding. I'd guess 8 - 10,000 of those shorts went through the 39 over the past 15 years. The truth is, shorts will allow erroding of the chamber (so will Long Rifles but it doesnt effect extraction like shorts) My chamber has that errosion but is still extracting LR just fine. If you shoot a lot of .22's through one gun, look in the bottom of the chamber for a depression just ahead of the case mouth. That is where the hot buring powder seems to eat away at the steel.
Another thing we learned while shooting all those Russian rounds is that even at "Target Short" velocity, penetration on critters is fairly amazing. The shorts had killing power beyond what the Vel/Ft Lbs would indicate.
When CB Shorts and Model 39's are mentioned, I'm reminded of warm summer evenings and fun days afield with my son. He and I still agree that those were the best of times.
Life is good....