For shooting a 1000 yards with precision is exceptional 20x glass good enough? As in a 4-20 ZCO. Or can we say the 527 is necessary? Serious thoughts. The other option is the TT 525. After doing the research the Kahles 525 although the same price doesn’t seem to be in the same class.

I would say good clear glass over magnification any day. 20x is plenty. I easily ran to 1000 with a 3-15 swfa. For me a finer reticle is important which is one reason I’m not a big fan of ffp.

#1 priority for me is repeatability and durability. Glass clarity is important, but not the most important. I've shot out to 800 and 1000 yards on 4x. But magnification is good, but most shooters get too much. A good 4-16, 4-20, or 5-20 or 5-22 is plenty. As you go up in magnification, your clarity goes down. And your mirage gets worse on the hot days with more magnification. I find a good top end is about 15x to 22x.

I've seen multiple shooters go for a Swarovski for long range shooting, only to realize the scope internals can't handle the dialing and repeatability. But the glass was clear!

Mechanics is my #1 priority hence my list. I just want my cake and eat it too. Great glass too. It’s a big investment for me but one I’m ready to make. The Mk 5 while having good glass did not dial as reliably as I like.

You can’t go wrong with either 3 you mentioned. TT is the top of the 3. ZCO doesn’t lag behind much at all. Khales would have the highest step off when compared to the other two. I own the ZCO 5-27. I would definitely own a TT also. Zero complaints here. Insane magnification isn’t necessary for 1000yd targets.

I’m pretty sure I’ve narrowed it down to the ZCO the consideration is the the 4x low end at 28’ fov vs the 5x low end at 21’. I don’t know which will make me happier, the 4x fov or the 27x magnification.

There is no absolute rule in magnification vs clarity. I'd normally say clarity is more important, but I'd rather have 9/10 clarity at 25x than 10/10 clarity at 15x if I'm trying to shoot 1000 yards.

Chad is right that repeatability and durability are more important than either mag or clarity, but with the 3 scopes you've mentioned those should all be good.

I really like the Kahles design. In terms of bang for the buck, a Kahles k525i used for under $2k is clearly the best value. In terms of overall performance, the TT and ZCO is splitting hairs. Are you hunting also? If so the decision gets a little more difficult. If not then go with the TT 525 or ZCO 5-27. If for nothing other than resale, I'd go 5-27. These are target scopes and the only buyers willing to buy a 315 or 4-20 is if they're getting a discount. The higher mag will hold value much better.

The difference in 4-5x is much much smaller to me than the difference in 20x vs 27x. When I'm shooting prone, 20x would feel like an enormous handicap. My Delta Stryker goes to 29x and I'm constantly between 25x and 29x when I'm prone or on the bench. I can't imagine spending zco money and being tied to 20x

Splitting hairs.


1.Tracking/ return to zero
2. Glass clarity
3. Magnification available

How big of targets at 1k?
I think glass trumps magnification..
years ago I had a USO 3-17x44 and was shooting at 1k and got a Kahles 3-12x50, it was an eye opener (bad pun intended) at how much easier it was with the better glass.

Too much magnification is not good either, you lose your field of view and it is harder to watch for impact due to muzzle jump.

5-25 is good for a dedicated LR gun.. 3-15 or 18 is also good, a bit lighter and more compact for a dual use LR and hunting gun

I settled on the Kahles 3-18 as it has great glass, I like the reticle (a whole different discussion), tracks right and is compact and light for what it is, I also really like the way they did the adjustments

What patriot07 said are very valid points when trying to decide between the two mags. My 5-27 sits on a 300 Norma AI. The measly 3 ounces of weight savings for the 4-20 meant nothing to me when compared to the other advantages of he 5-27 for the rifle I use it on. I do hunt with my 300 Norma. It’s not a pig when it comes to weight but isn’t a lightweight either. She sits around 10lbs fully dressed.

This is a few years old but I found it very interesting. https://precisionrifleblog.com/2020/09/05/best-elr-scope-and-scope-mount-and-rings/

I read that a couple of days ago, it’s a good article. ZCO was only two years old, it has a much larger following now.

They did that post several years, I wish they would continue. That’s the last one.

I am not really friends with the author and creator of that website but I know and have met him. He is a very busy man. For what it is worth the scope he uses is a 7-35 ATACR and he has several of them. Nothing at all wrong with TT, ZCO, or Kahles but any particular reason why Nightforce isn't on your list? The 7-35 ATACR seems to be the gold standard for long range shooting. I don't doubt at all that the TT, ZCO and maybe even Kahles have slightly better glass but there is a huge price jump and I wonder if the difference is really that significant. Nightforce tracking and reliability is second to none.

I concur.

Actually according to that writer NF is second only to Kahles in tracking. Not try to be argumentative though. NF is a great scope by all counts.


I do not want a NF for the same reason I do not want a 6.5 Creedmoor. They are both great tool to be sure. It’s mostly because I’m hard headed and childish and do not want to be like everyone else. Terrible answer but honest.

Not to worry though, at the rate I’m going I’ll be mounting the scope on a longbow.

"That thing over there works. So I do not want it."

So you do understand.

For the record I’m not looking at things that don’t also work.

Well… anymore. I was think the Mk5 5-25 would be a hit and I took a reliable SS 5-20 off to do it. It sure is nice glass but pretty is as pretty does.

I’m going to have a heck of a time selling that Leupold if I keep bad mouthing it.

I seen em fail to track also.

If memory serves, we told you that was a possibility.

Way to go, Buzz II.

Idk, I think I bought that in a spastic moment with no research. I tend to do that.

And I have had it a couple of years and actually do shoot it, so maybe it’s Buzz 2.0.

I think right now the next tier down from the ZCO and TT is the Vortex Razor GenIII
I have all the scopes mentioned above except ZCO which I have played with but not owned. My TT was a great scope with amazing turrets that has such tiny numbers and closely spaced clicks made it hard for me to use with 68 year old eyes. I have the big ATACR as well but I find myself using my Zeiss S3 and the Burris Pro more because of better FOV and I just don’t like the way the magnification ring the whole eyepiece turns.

Also have Kahles and it is a very high quality feeling scope and love the parallax adjustment but CA is very apparent compared to other even cheaper scopes.

I shot my first 1000 yard match with a 3-15x and never thought about needing more at that time.

We shot Jason's range out to 800 with a G1 PST 2.5-10 on a .308. That scope isn't known for it's amazing glass and 10x isn't much mag at that distance.

I often wonder how much 'clarity' is actually a focus issue between shooter and scope, and not a glass issue.

Three things on clarity.

1.Glass quality
2. Focus setting
3. Mirage

Mirage is one of the several reasons I like first focal plane. There's not a scope out there that can beat Mirage 100% of the time. Get a hot, clear day, and it can be rough past 500 yards. Even my NF ATACR 5-25X is not immune. There's times I can't use 25X, and I back it down to 18X, give or take.

And maximum magnification is not going to be maximum clarity, almost always. Back down from maximum just a bit, and things often get more clear. But, generally that is for scopes over 15X maximum.

At everyone suggestion I just laid hands on a 7-35 NF. It’s on sale at that. I didn’t buy but I gotta say I don’t have any negatives.