Mmm... I'd give it a qualified 'maybe'.
In the distant past, I spent some time messing around with a Redding body die (sizes the body and shoulder) combined with a Lee Collet die - back when 'neck-only' sizing was still a thing
It worked better than you might think... but doing it all on a single stage press was more than a little tedious, and the LCD had it's own set of quirks that 'ate' more than a few pieces of carefully groomed and prepped Lapua brass
I want to say that I *think* I had one of those Forster shoulder bump dies for a while. I'm pretty sure one of my team mates - John Weil (Team Savage FTR, back when) used it at one point, which was what enticed me to try it. I honestly don't remember anything about it one way or another, other than a) I sold it and moved on, long ago and b) nobody I know actually uses one. Or if they do, they're keeping it really close to the vest
On the surface, though... they sure *sound* like they should do what they say... the question being whether you *really* want your brass to be that closely formed to the chamber, or not. Even for BR/F-class, which are relatively 'clean' environments (individual ranges/matches where you get sand or rain blowing in the chamber aside), you generally want *some* clearance around the loaded round to allow easy chambering so as to not disturbed the gun in the bags. One could argue that would be even more of a concern in field type conditions I.e. PRS/NRL, hunting, etc. where a round that is a little too snug when closing the bolt can move you waaaay off your point of aim and cost you time/points getting back on target.
The one other thing about Forster bushing dies is... they don't use the standard Wilson/Redding 0.500 x 0.375 bushings. So if you're heavily invested in those already, you'll have to buy all new bushings to work with the new die. That might have been what killed the deal for me, back when. Nowadays... people are a lot less shy about spending $$$ on dies, etc. so maybe less of an issue. And of course, dies like the ones from Cortina, SAC, Neil Jones, WTC, etc. come with neck/shoulder bushings, so you'd be buying new bushings *anyways*...
