i know a long time ago we were told never to dryfire guns. we all know it doesn't hurt a centerfire rifle. i spend time measuring pull weight, and practicing trigger control. question is i am going to tackle a 10/22 and want to know if it is harmful to dryfire a 10/22?

It can be. What I do is put a spent .22 case in between the bolt and breech so there is space and the pin does not hit when the pin strikes. I have also heard You can chamber a SPENT case and do it that way, just rotate it so the firing pin hits a new spot every few strikes.

It CAN and will damage a centerfire over time!!!
I'm sure you might have hundreds of "practice" fires on a gun.
Spend the 12 bucks and get some Snap Caps in you caliber.
Then you can practice all you want.
Using a spent case will work a few times but it ny no means takes the place of a snap cap.
I have never seen Snap Caps for rimfire.
You must decelerate the firing pin.. it will choose to break on you @ the worst time..

Something about dry fire just rubs me the wrong way. I do not care to see someone do it. It just doesn't make sense to me to pull the trigger on an empty chamber. JMO
I guess I could see the need if you are gauging (Adjusting)the pull. A snap cap should be used in that case.

On the rimfire the pin will hit the top of the barrel and it will damage the barrel and pin. I know the old ruger pistols were bad about wearing and ruger would throw the barrels away if there were any marks at all.

On ceterfire it is just wearing the pin against the hammer lug and bolt.

On another note, many of accidents have happened by people dry firing in the field thinking the gun was unloaded. Maybe that's why I don't like it.

"I keep a small bullseye target...in my study, and several times a week I take a rifle out....and practice squeezing off a dozen or so dry shots at the bull. ...I go out in the back yard with a rifle and squeeze off ten from sitting and 10 offhand...
Dry firing on an empty chamber should be avoided with a rimfire rifle, will not hurt most centerfire rifles."

Jack O'Connor, The Complete Book of Rifles and Shotguns.

I have several rifles from the '50's which have been dry fired a bazillion times. Never had a firing pin problem.

suit yourself...
I't just a suggestion, you are causing some very hard 53-60 RWH steel to contact each other in ways they are not desinged for.

The late Harold MacFarland (master gunsmith and author) noted that excessive dry firing was the number one cause of broken firing pins.

If you dry fire to improve trigger control; use good snap caps, in good repair.

http://www.amazon.com/gp/product/B001ENG...1C2BRVSXXY2310R

or

http://www.amazon.com/Plastic-Safety-Snap-Caps-Per/dp/B0018DYGSA

they are a must with rimfire