These are what I run.
https://www.chamberchiller.com/USB-Centerfire-Chamber-Chillers/RH-USB-Bolt-Action-223-308
Plenty of air volume and almost silent. I have one of the older versions with the smaller fan that used AA batteries. Get the USB version and run the small battery pack. The AA battery version eats batteries pretty quickly. I have had no issues with the bolt action version or the AR version. They seem to cool the barrel down pretty quickly without the annoying whine.
https://www.chamberchiller.com/USB-Centerfire-Chamber-Chillers/RH-USB-Bolt-Action-223-308
Plenty of air volume and almost silent. I have one of the older versions with the smaller fan that used AA batteries. Get the USB version and run the small battery pack. The AA battery version eats batteries pretty quickly. I have had no issues with the bolt action version or the AR version. They seem to cool the barrel down pretty quickly without the annoying whine.