I was reading about this. I haven't got to shoot one yet, but its a pretty nifty idea igniting the powder in the middle of the charge instead of at the rear.

For those of you that didn't see. Knight have a new breach plug to be used with loose powder only. Its bascially a stem about 1 or so inches long. when you put the powder in you gun, it goes around and on top of the stem. When ignited it goes towards the front of the charge. They get a tad bit of velocity gain, but it is supposed to cause more consistent burn.