I purchased the RunCam Scope Cam 2 4K (25mm @ FOV 12°) for use on a gel ball blaster rifle (in QLD, AUS) and it works great. Though I am using it primarily as a 1920x1080 60fps camera, the price difference between that and a 4K camera was too small to debate. Recording using a smaller resolution gives you more SD record time. I suggest using the biggest SD card you can afford (go big or go home), then your only limit will be battery life between charges. Nothing a battery bank can't solve (at lunch time) when recording all day out in the field.
The RunCam fits perfectly to a 20mm picatinny rail (plastic or metal) and whilst relatively light in weight, its built as solid as a tank. Though the securing bolt has a small foldable semi-circle fingerhold on the end of it so you can finger tighten the RunCam to your rail, unless you have fingernails to lift the fingerhold up, you may find it hard to access to tighten. Instead, I just use the common screwdriver slot build into the bolt head to (really) secure it to the rail. After all, you don't want to lose your RunCam to the bush floor; you will never find it again due to its size (small) and colour (black).
Connecting by Wi-Fi initially was a bit of a problem, but once I took the time to read the manual it was a piece of cake.
Connecting by Wi-Fi is needed to configure the RunCam settings to your liking. Once setup, you will only ever need to use the USB cable to either charge the RunCam or download the recorded MP4's. Once I have downloaded the days recordings, I format the SD card to wipe it clean. When turning the RunCam back on, it re-creates all the necessary folders and files (with no perceived delay) to get it ready again for its next recording session.
Being smart and only turning the RunCam on (and off) when you know you’re going into action instead of just leaving it on permanently (for a whole game or the whole day) not only makes for smaller file sizes / easier post production, it will also prolong your battery life for the day.
Lastly, being a RunCam, it primary use is for recording action down the barrel. Unless you are using the 3.6mm@FOV 150° on a pistol, the RunCam is not really designed to capture wider angle field of play / general situational awareness. For that you should use something like a GoPro. Trying to capture overall field of play on a RunCam makes for a shaky tunnel vision recording with no reference to the wider field of view or surrounding conversation(s). IE: It compliments other wider angled cameras on your blaster / person.
I highly recommend this RunCam.