This new crimp die is something I haven't used so I can't say that it is or isn't the answer to weak crimps for revolver bullets. One thing for sure, the price is right, so it should be worth trying if you are having trouble with bullets slipping their crimp.
I have written previously on thes forum regarding the matter, but will breifly explain my method of obtaining the strongest bullet grip possible. I'll give two methods. The most precise seating depth process requires seating the bullet with the crimp die adjusted so it doesn't crimp during seating, and so that seating places the end of the case in alignment with the crimp groove. A second pass through the die is done with the crimp die screwed in at least one turn past where the crimp would be turned in, and with the seating punch backed off so it doesn't contact the bullet. The crimp is then applied with a careful feel on the press handle. When you feel the crimp turn in, and bottom lightly, lift the lever and take the cartridge out.
The second method is to seat bullets with the crimp die screwed in deep as outlined above, but apply just enough pressure to close the crimp. This method doesn't hold OAL as precise as the above if cases aren't trimmed precisely, which I have never done with revolver ammo..
In my experiance, which is limited to 44 magnum with bullet weights to 400 grains, bullets jumping the crimp have never been a problem with the above methods. This because it eliminates brass being bulged below the crimp from too much crimp pressure. If one is using a progressive loader, the second method will of coarse not work, but the first will, with a second crimp operation.
This new Lee crimp die will also require a second crimp operation. -- I do have some question about it making a strong enough crimp for heavy revolvers if it is used to crimp where there is no crimp groove. I won't explain my reasons for questioning it, because I don't have experiance with it and my concerns may be entirely unwarranted.
Please inform us about how it performs if you get one of these.