I bought my Beta Master (not the other way around...lol) back around the early to mid 90's, and it's shown me on several guns, where they weren't shooting anywhere near book velocities, as previously mentioned.
Although I've never shot mine, or had anything hit it, I can see where that can happen pretty easily.
Through wear & tear, and regular use, mine is getting kind of tattered, and I recently looked into sending it back for reconditioning.
For what it costs to have that done, the company offers an "upgrade" to the next model up the ladder.
For $30, and my Beta Master, I can upgrade to the "Gamma" model. Far cheaper than having my old one reconditioned, for sure.
Anyway, the Shooting Chrony has been a great inexpensive chronograph for me, and has worked flawlessly over the years.......and I've used mine ALOT.....well worth the money.
Take care,
Bob