Hows the 1/3 co-witness mount like when using daniel defense iron sights, are the iron sights still usable without taking optic off? — 2 Answers

Yes, the irons are still usable. The sight picture you will have with the 1/3 LCW is your irons will appear in/through the lower third of the dot sight, with the dot hovering maybe 1/8”-1/4” above the iron sight picture. The idea is to get the dot aiming point away from the irons, as you do not need perfect cheek weld or alignment with the dot to hit your target, unlike the irons which require you to line them up every time. The cheek weld with the 1/3 will be slightly looser than the tight cheek weld you should have with your standard height iron sights. 1/3 mounts allow you to better/fully utilize the strengths of a dot sight from any position or angle… if you see the dot on target, pull the trigger… keeps your sight window more open and less cluttered.

Inversely, some prefer absolute cowitness, where the dot will sit more or less right on the tip of your front sight post. Some prefer this, but it really does just take away from the versatility of the dot sight, it doesn’t help you shoot better with your irons or with the dot… just consumes real estate in your field of vision. The only advantage of an ACW mounting is the exact same cheek weld for irons or dot.

So if you’re an old dog that can’t learn new tricks, you’ll probably want the ACW, probably better with folding sights or at least a folding rear. If you want to run fixed irons and train with your dot sight as it is intended/capable of performing, go 1/3 LCW, just realize you’ll have to train to not get confused between dot and irons, and to loosen up your cheek weld for the dot sight, same position just not down tight.