Dry firing a GBB
 

Is there any harm being done dry firing a GBB? Since there's no piston slamming forwards without any BB resistance slowing it down I figure it would be ok. Any thoughts?

This topic has been discussed in the past. Some gas guns won't cycle properly without a BB chambered. Due to the different valve systems, a lack of a BB may send more gas to the blowback chamber, causing excess wear. I know on certain KSC Glock models, dry firing without a magazine will quickly break a certain part of the hammer mechanism.

ah yes, forgive me, I didnt see it the first time I searched. Thanks for the reply anyway. I think I'll just not dry fire it then...:)

The problem dry firing with a KSC Glock without a mag is BS. The only way to break the hammer is to release the hammer while there is NO SLIDE on the frame. When there is no slide the hammer does not hit the hammer impact block, and allows the hammer to come crashing down on the hammer pin. the pin is what will break, but that ONLY occurs without a slide on (because the impact block is on the slide)

Any thoughts about a KJ M9 then?

Yep
 

That's right. The Glocks have a really delicate pin at the back that is damaged on dry fire, but ONLY when the slide is off. WE covered it in the GBB clinic yesterday..

:-)

So I can dry fire my KSC G19 to my hearts content as long as the slides on and I'm not going to break something or cause excessive wear on any parts? I guess any sort of motion is eventually goign to stress the hammer more and more and in time it will break but it's not any sort of major acute damage?

I believe there was an internal part that breaks on the KSC Glocks if you dry fire them too much, I know what the part is, but I don't know how to describe it... haha, get me a exploded view and I'll point it out.

Any type of firearm, and their airsoft versions, should never be dry-fired.
Why? Because in normal circumstances, there is a reaction to the hammer or trigger pull that compensates any impact or release of a hammer/pin/spring.

The metal parts can become brittle, and snap. I've seen this happen with even real tempered steel gun parts. So in general it's a bad idea.