I've got a Mark 6, 1-6, CMR-W.  The illumination of the center dounut is more than brings enough to get quick acquisition with two eyes open on low power in the daylight.  It's not as bright as a 3MOA red dot, but it works just fine. Last week I picked up a Mark 8 3.5x25, Tremor2, 2016 mfg date.  I went with the illuminated version, both for twilight shooting and also to help with seeing a center when on low power. My hope is that on low power magnification with illumination I would be able to pick up the red dot for quick targeting. Before I mounted it up I replace the battery, as it was completely flat.  Even after doing so, and trying a second battery to confirm, the illumination was much less than I expected. On high power I was able to see dots with the power setting from the highest 7, down to 5.  Looking through the scope in a darken room, the lower power setting do illuminate to the lower settings down to 2.  With the scope on low power, I see no illumination in daylight, and in a darker room I loose illumination after 4 on the illumination setting.

I contacted Leupold and the said to ship it in so they can go through it.  I'm hoping it is just a warranty issue.  They have really gone above in my previous interactions and I'm sure they will this time as well.  Still, I need to know if my expectation is unrealistic, and maybe related to how illumination works with a Horus reticle. Still, I would hope a red dot on low power in daylight wouldn't be asking too much....but maybe it is.

This is my first high end hi power scope.  I did have an illuminated Vortex Viper PST 6-24 with an ebr2 reticle that was bright enough to see in daylight across the entire magnification range.  Does anyone else have an illuminated Horus reticle, either Leupold or anyone else, and if so, how does it up in daylight?  Does the entire tree light up in darker conditions or are there just specific dots of red? How about low power...can you see a red center?

I could be wrong, as I've never played with the 3.5-25x version of the Mk8, but I've owned and played with quite a few different high end scopes that weren't LPVs and NONE of them had what I would call "daylight bright" illumination or a super bright center dot.  

Honestly, it's not really a requirement for most end users as the majority of them aren't going to be using a higher magnification optic like most use a LPV, as a workable substitute for an RDS.  

I'd be interested to hear from others with experience with the Mk8 3.5-25x, but my educated guess is that the Mk8 illumination isn't supposed to be anywhere near as bright as the illumination on the 1-6x Mk6.

ETA:  Also to add, different versions of the CQBSS don't have "daylight bright" illumination either.  Daylight bright illum is only available with the H27D and 7.62 CMR reticles.  The TMR and Mil-Dot reticles have fairly weak illumination.

The illumination levels on every Horus reticle I've seen have always been very low, especially compared to other reticles that can be daylight bright.  They are generally optimized for low light conditions, since higher levels tend to "splash" or "flare" and cast light in unwanted areas of the reticle.  

Most Horus reticles are illuminated at strategic points within the reticle, per the Horus spec.  I have seen a Tremor3 in a US Optics that was fully illuminated.  

There's likely nothing wrong with your scope, it just isn't what you expected.  If you do want brighter illumination, Leupold may be able to increase it beyond their normal spec.  You'd have to ask them, though.  

Thanks guys.  It definitely isn't what I expected after using the Mk6.  Leupold has it now and should be giving me a call next week based on the estimated queue time they emailed me after receiving it.  With 7 brightness levels I hope they can tune it up a bit on the top end.  I will be sure to ask.  Thanks again for the feedback.