Darren, I perhaps did not adequately express myself, and I apologize.
Given the many complaints I hear on this site and in real life about the escalating cost of the hobby, some compromises will need to be made. Being able to purchase a really excellent add-on barrel like this one for this price perhaps means a little sacrafice in clarity. I probably should have added something along the lines "not for the first-time AM barrel user," and if James wants to add that to the review, I'm fine with it.
In my case, I don't really care about the lack of instructions, as I've purchased AT LEAST 25 AM barrels in the past year, including a half dozen Tiger Is (yes, I have that many in my stash right now or on the workbench).
There are good resources on the 'Net, too. For example, Dave Byrden's terrific web site where he has some very marvelous
CAD images of a Tiger I muzzle brake that will help one sort this sort of thing out. His site is also excellent for pointing out the flaws of ALL the major (and some minor) Tiger kits, allowing the perfectionists like myself to build the best possible Tiger in plastic.
If you have the dough, I would recommend the Aber or Voyager version (the latter
reviewed by me here). But if money is an issue, then the JBModels.eu barrel is the clear choice IMO.