Hoping for some top quality advice again please guys..

I've seen some comments online regarding the setting of head space on various different target rifles. Also a friend at my club has experienced some problems with cartridges sticking in his KK300.

I'm wondering if getting a KK300 is going to limit my choice with regard to ammunition. I'm also wondering if head space can be easily adjusted on a KK300 and how and why this might be desirable.

Sorry if I'm sounding a little vague...it's because I am. I've little experience of rim fire as yet nor familiarity with the mechanics of various systems.

Simon