pwm,

Quite frankly, I don't know anything more than Collath's name and I had heard (or read) somewhere about their proprietary bore and caliber system. Thanks for giving the very interesting information - this is exactly the kind of information that learners like me try to get from more experienced people on forums like this.

And please don't call me "sir" - I am neither too old nor eminent for me to be called that.

Do keep in touch - I just might want to bug you with more questions since I am only now trying to learn about guns.

In friendship,

Mehul Kamdar.