One major flaw. - Vortex Impact 4000 Ballistic Rail-Mounted Laser Rangefinder

I'll start with a potential problem that may be related to my specific unit, if it's been off for anymore than 2-3 days it will not turn back on without removing the battery. I feared it was passive draining the battery and had died in the first week but removing and replacing the same battery allowed it to power on again. A small frustration at worst and so long as I do this before going out to shoot I'm good for a few days before this problem repeats itself. Now for the design flaw, the unit needs recalibrated if you travel more than 30 miles from where you were when it was last calibrated. So unless you have one range in a particular area, or hunt in one space where zeroing a rifle is possible in the field, you'll need to recalibrate often. This is problematic as calibration requires the unit to be removed, meaning potentially needing to rezero after remounting. I've circumvented this issue with an ADM 170 QD bipod mount and a 17 to picatinny adapter, giving a rock solid, low profile, and repeatable QD mount to this device that's held within +/- 1 moa out to 1,000 yards after recalibration. The Impact 4000 might be thousands of dollars under the price of any similar item on the market but you'd think knowing the device needs recalibrated like this that Vortex would opt for a QD system. If you don't hunt in an area within 30 miles of a range you can zero in, or in an area where you can zero the device in the field, it's difficult in it's default configuration to guarantee your zero after recalibrating in the field. This is a major design flaw as hunting is one of the only practical applications to an on rifle range finder and ballistic calculator. Granted, the shift in zero is small enough that hunting in mid ranges may not see a large enough shift to turn a hit into a miss, there is a chance your optic will be on target and the device be off enough to be ranging and calculating for a spot behind your target. All that being said, everything that the Impact 4000 does, it does amazingly. I've not been more than 1-2 moa off on any adjustments made via the calculator, and there is always the chance that was ammo or shooter related and not device related. It handles 300 norma recoil just fine. It picks up even matte or muted targets out to the 800-1100 yards I have to play in and calculates external environmental factors very well for something using default data for an area vs specific data like linking to a kestrel would. The app is optional, and everything can be done on the device itself. A huge plus but also a little cumbersome when initially setting up. But once your set up and you've become proficient in navigating the device it's quite quick and seamless. Even at the range with known target distances I've used this often instead of my dope card, especially given the drastic temp changes in my area and my dope having been done over the winter. All in all it's a great tool for ranging unknown distances in the field quickly, developing dope cards or changing a dope card for the season, or getting rough environmental data to get on target fast. It doesn't do any specific task better than a dedicated item would do that task, i.e. a kestrel still does environmental data better, but it combines them all in a nice little quick and easy package for much, much less than any current competitors. It's a niche item, but it fills it well.