RE: ballistics question
Fouling can be different, companies use different types and brands of powders, even different bullets can foul more or less. The Win BSTs are molly coated, it is highly debated but many feel they foul less than say copper jacketed bullets.
The barrel legnth can help to a point but this is now a highly debated topic thanks to technoligy. Some of the newer powders used in SOME short action rounds can have the bullet up to speed in as short as 18". Experts debate that the shorter stouter barrels are effected less by harmonics and ultimately fire better long range and retain over 95% of the bullets speed compared to a longer barrel. I am not going for or against this theory, waiting for more proof and information. I would think that the .243 being a little smaller round than say the short action .308 win would benifit from the longer barrel as it will stabilize the bullet a little better. Many other rounds especially mags. (7mm mag, 300 win mag and the like) need the longer barrels to burn their huge, slightly slower burning powder charge completely.