I ask for enlightenment on .22 and .17

[Scarecrow Repair]

A friend picked up a box of what looks to me like .17 rounds. It says .17, it says magnum, it says 17 grain, and they look like miniature 5.56 rounds compared to the .22LR I am used to. My friend bought them thinking they are .22 magnum, and by gum the cartridge case sure looks identical the the .22 magnum he has. But the bullet isn't, it looks sub caliber, like, say, oh I don't know, maybe .... .17?

So, question 1. Is this a real .17 caliber round, or is it a real .22 caliber round?

Question 2. Are .17 caliber rounds based on .22 caliber cases, and only the bullet is smaller?

And question 3. If this is the case, can you fire them from a .22 magnum revolver? I suppose there are three categories of answer here: NO it is dangerous, Yes but it is useless, Yes and it is quite useful. Will the bullet expand like a minie ball to seat against the rifling and come out fast and accurate, or will it rattle down the barrel and come out slow and tumbling and generally useless except for laughs?

[Vepr62]

.17

It is a .22Mag necked down to .17 with a jacketed bullet and it is a BLAST to shoot out of rifles. The balistic is far superrior to .22Mag and the round is still supersonic out beyond 200 yards. It won't expand in your .22 revolver chamber, so basicaly it is useless.
Vasiliy

[ivanimal]

17 hmr is the brain child of Hornaday MFG. they have a winner here. It is useless in a 22 caliber gum it will start to do funky stuff right out of the barrel with little consistancy. Now there is also a H2 which is a 22 long rifle necked down to 17 as well. Go and buy a rifle in 17hmr if you like to squirell hunt.

[mscales5]

There are actually 2 .17 rimfires. The first one was developed by Hornady and Ruger. It is the Hornady .17HMR (Hornady Magnum Rimfire) and the new MACH 2. The .17HMR is a necked down .22 magnum case to .17 and travels to speed approaching 2600fps. The .17 MACH 2 is a .22 LR necked down to .17 using the same bullet. These are guit fast and are very destructive to squirrels. I have been converting Ruger 10/22s in the Mach 2 and they a e a blast to shoot. Not cheap. but fun.