Hi Jockey, I've tried it and it's excellent. I'm a target rifle shooter as well as a stalker and I use .308 exclusively for all my shooting. My experience with Thorroclean has been exceptional. It is a highly effective cleaning product and gets rid of fouling that many other products don't touch - especially if you want to address the build up of carbon or copper fouling in your barrel - and especially in the front of the chamber where carbon rings have a tendency to appear. As a competitive shooter, I am extremely particular about the accuracy of my barrels, and I absolutely wouldn't clean with a product that would be harmful to either the accuracy or the life-span of my barrels. In my humble opinion, Thorroclean is extremely effective, but not necessarily essential to use every time you fire a few shots. For most stalking rifles, a more basic clean using more conventional methods is probably more than adequate - each to their own.
The most important and game changing gun cleaning accessory is a bore-scope. Without one, you cannot hope to actually see how clean/dirty your barrel is, so I'd thoroughly recommend getting one if you really need to see if your cleaning regime is effective at getting all the fouling out!
The reference to Bartlein barrels - I've just been on their website, and there's no reference to Thorroclean on there that I could see. They make reference on the cleaning page to using Remington 40x, and Thorroclean works in exactly the same way - Thorroclean is basically an ultra fine abrasive (Iosso) in suspension of the liquid. It is perfectly safe to use as long as you flush it all out after the cleaning phase with the Thorroflush or another adequate solvent of your choice.
Thorroclean is used by serious competitive shooters - have a look on Youtube and you'll find people like F-Class John and Bryan Litz who will tell you what they think.
Cheers,
Jon