I've read about these things in Fadala's books - but never talked with (much less seen) anyone who used one. Anyone here have experience with 'em? Seems like they could only get repeatable results on the first one or two shots after cleaning - after fouling builds up I would think that it's anybody's guess as to how much pressure was put against the load versus the fouled bore. Experience is really what could answer this - Are they worth buying?