Sooty Cases=Underpowered?

[Potatohead]

Thanks for your comments everyone. I very much appreciate you all sharing your wisdom.

Can anyone sum up locked breech and blowback, or the differences therein? I have a general idea of course. I guess off topic is ok since Im the the originator of the thread? The 2 pistols I have are an sr9 and p238.

 

[Walkalong]

In an auto pistol a locked breech action stays closed until the pressure dies down before it opens and everything starts moving rearward, extracting the case and breaking the seal the case has in the chamber. On a blowback everything starts moving almost immediately, only being held back by the weight of the slide etc., breaking the seal right away.