You need this - Geissele Super Precision ACOG Series Scope Mount

The Geissele mount is a vast improvement over the stock unit. It has several features of which, it can be mounted and dismounted without needing to re-zero the optic. I use the Acog for home defense with a red dot on an Arisaka mount. I can remove it and use a distance scope for long range when needed. After the long range shooting is over, I just pop this back on in the same section and the zero is dead perfect every time. Works great and the machining and finish are second to none. If you swap optics on your rifles like I do, this is a must have. Take the plunge, you won’t be disappointed.