Let me clarify!! Shortest configuration with stock deployed. I assumed that would be a given as that is what the ATF guidelines state.Lyapunov:
I tend to use the numbers HK publishes for overall length for the model in question. If you one of the Hk Law Enforcement catalogs it will have some info you can use.
Looked up the Hk MP5k-PDW stats for you: Hk says the PDW barrel is 5.5 inches long and the overall length is 23.74" with the stock deployed. I think that Zenieth
says its PDW barrel is 5.8 inches on its web site. I have heard that the ATF wants the overall length to be with the stock deployed i.e. the longest configuration.