I use one on my 98B 338 Lapua mounted on a nightforce 8x32x56 and have used it on a 416 as well and can tell you they work. The great thing is that when you develop your load you just input the data into the software program, save it, upload and done. Custom hand load = custom program based on your load data.
Once you call up the saved library on the bors you zero your rifle at 100yds and hit confirm again done…
The battery is about 30hrs but changing a battery does not loose your program or setting. No problems yet but I'm always carful to return my turret to 100yds when done so at worst case all I would have to do to reset would be to turn it on and as I'm already set at my 100yd zero I could just hit confirm and I'm up and running.
All in all I don't regret buying mine and would do it again in a pinch. The software is easy to use; you just have to play with it… One note is that once you save a custom load you loose all the loads that were on there from the factory but to me it was no big deal as I want only my loads with my confirmed data on it.
Hope this helps…