I had bought one once and then I read a gun cleaning test someone did with a boresnake and regular cleaning rods/patches/brushes. The regular method came out cleaner. The bore snake kept the fouling imbedded in the snake so every pass you were re-introducing fouling back into your bbl. Carbon is pretty grittty stuff, so running a carbon impregnated boresnake through your bbl won't do it any good.
Bbls are like women. Every one is different. Some like it really clean, some like it really dirty. Some are in between. Some like 2 fouling shots, some like 5. I shoot 6-8 different custom guns at our fun BR matches and every bbl is different. I don't clean for 70 shots. A couple of guns should be cleaned around 30-40 shots, I notice the accuracy dropping off. Most of the guns stay good. I clean with Patch Out and Accelerator, sometimes nylon brush. With my cleaning regime, most custom bbls only need about 10 patches, no brushing to get clean.
I've read on BR Central that some .30 cal Hunter BR shooters don't clean for over 300 shots. Their accuracy does not suffer. .30's act differently than 6mms though, apparently easier to stay in tune.
Cheers
Greg