I wonder if Mr. Knows-All-There-Is-To-Know, the previous reviewer, ever went to the trouble of building and testing the designs in this book that he denigrates, or if he was too busy trashing books about these and other tactically useful suppressor designs, while at the same time writing glowing reviews under other names about the pop can and other improvised models, not to mention posting fraudulent reviews of other books while IMPERSONATING another reviewer who has ONLY reviewed this title and the other title by this author, and in doing so always squeezing in a line about how people should "search the web" for silencer designs, a set of search terms that Uncle Sam almost certainly has Google tracking for them.
To top that off, several months after posting this "review" of this title, Mr. Knows-It-All also posted afterthought reviews of three other "reference" titles under this same username, posting all three on the SAME DAY. This is a painfully transparent attempt at establishing credibility, and there can be little doubt as to who he works for.
When something becomes a lightning rod, you know it has to be good. Somebody doesn't want people knowing how to build these things, and when you look at this video by someone who did the work and testing, you'll see why. Appears they work pretty dang good to me.
The author of this book detailed the torture testing that was done with a .223 model. Four mags through an M-4 type rifle, full auto as fast as the clips could be changed. Burned the black coating completely away, but other than needing re-coated, zero damage.
If a seam in an outer tube did split, and one never has on one of these, you know what would happen? A crack would develop. Some noise would escape. You'd have to weld it back up or at worst make a new one. And in building over a hundred of these in the course of R&D, not a single one ever "blew up" on the author while firing, shooting the holes through the baffles, or at any other time. Special care IS required when working with semi-auto pistols however, and that is detailed.
Couple other things. The galvanizing on the parts involved is much too thin to significantly interfere with the welding. Galvanizing can be removed if you prefer, but welds are perfectly solid either way as long as you can get the hang of welding, and the book provides basic welding instruction too. The softness of the freeze plug baffles is only a problem for the very first one, in rifle calibers only, and even then only if you don't make a solid blast baffle as instructed. And in fact this softness is necessary for forming the baffle to the desired gas-redirecting shape, which is the reason they are used instead of the old method of fender washers.
This book isn't for people with a fancy machine shop, it's for people who have a welder (even a cheap 110v model), but no lathe, milling equipment, or reloading equipment. While there are more advanced baffle designs that can be made in a fancy shop, this type of design is still in use commercially, and it is made much more effective by use of heavy stainless diffuser material between the baffles, something commercial cans don't use because it affects longevity. (But when you can rebuild the thing for $20, who cares?) It is the best suppressor you can make with these construction methods, and whether the previous reviewer likes it or not, these suppressors are very comparable in performance to commercial models.
I wouldn't go quite so far as to put one of these on an M60 or an M249 without stronger seamless tube, (available from Aircraft Spruce), but many commercial cans are not rated for those weapons either. For an M-4 or M-14 on duty however, or a sniper rifle in .338 or .50 BMG, these will do the same job as the commercial models and just as safely, and they can be constructed on-site by military units, security contractors, or others that don't have funds for commercial cans.
If "NFA Manufacturer" can build one of these suppressors properly and then make it blow up, perhaps he'd like to post the video for us instead of running his mouth off about what he just knows will happen. (If you do, Mr. NFA, just make sure to show the number of continuous rounds it took to break it, and without fixing it to break first. I'd love to see that myself.) In the meantime readers, get this book before Uncle Sam finds a way to make sure you can't!
P.S. The reason the book doesn't discuss the effect on bullet velocity is because there is no effect. The bullet does not touch any rubber wipes and is therefore not slowed down nor accuracy harmed as a result.