I'd dearly love to know *** your friend is doing to his, to have such problems with relatively 'light' calibers.
Don't get me wrong - I had my fair share of fits with mine out of the gate. Wouldn't trigger reliably via the microphone, so I had to use the Doppler trigger - which requires considerably better 'aiming' of the unit relative to the bullet flight path to get it to trigger consistently. Finally got tired of bitching about it, and got in touch with the rep... we went round and round about it, because yes, I'm fairly well versed in "reading the fine manuals". Sent it back, they said they tested it with .308, suppressed and unsuppressed, and .22LR as well, no issues.
I ended up having to get more picky about the positioning and alignment (much closer than the manual stated) to get it to work the way I wanted, but in the end, it works just fine. I already had an aftermarket USB battery pack, so that wasn't a big deal for me to use it with the LR.
I also got the Piet recoil trigger mentioned above... mine doesn't work quite as reliably just draped over the gun as he demos, but attached via velcro it does fine.
I still have my MagnetoSpeed v1, and it's still chugging along. My only complaint is that the new mounts for attaching it to the stock, not the barrel, won't work with the v1. Homebrew is the only option there.