RE: ballistics question
Ridge Runner is correct, you will gain the difference 35-55 fps per inch of barrel in the 243 depending on the load. But atleast the 35fps for sure. Shorter barrels do not fire the bullet the same speed as the longer barrel. The smaller the caliber the faster you gain speed per inch the bigger the caliber the slower you gain speed per inch. This I've tested and know it to be a fact even in pistols.
Your second ? You need to know the speed of your bullet to compare it to the ballistics chart. Also if you live above sea level and depending at what elevation you bullet will lose less elevation drop due to air density. At 7500 ft this starts to really effect the drop and at 10,000 you just turned your regular 30-06 into a magnum class of ballistics at longer ranges.
Fouling may be caused by a softer jacker from the core-lokts.