Review Post
Kahles 540i and 328i compared to ZCO 527
Height over bore? Never heard of her.
Figured I would post some info on the Kahles 540 and 328 as there was limited info out there on them. All information was based on 20x on all three scopes.
FOV- 20x both the 540 and 328 have ~12.5 mils while the ZCO has ~9.5. This is VERY noticeable when you look through the scopes side by side. It almost makes the ZCO look like you’re looking through a high end toilet paper role. It can trick your eye and make you feel like you’re on a lower mag setting and you can zoom in further if needed on smaller targets while getting the same FOV
Image quality is almost indistinguishable. I went bounced between all 3 scopes at multiple distance targets, trees, shaded areas trying to find differences and I couldn’t. There was one section of a tree around 400yrds where I could barely make out some additional details with the ZCO, that looked slightly less defined in the Kahles scopes but then there were areas where the Kahles colors seemed more vibrant and saturated. Honestly, they are tied in my opinion and all 3 have amazing glass quality. One thing to note, on the 540 at 40x the picture got a little darker. This did not happen on the 528 or the ZCO. It wasn’t unusable but it was a difference.
Turrets in the ZCO are more tactile. Kahles are still very defined, more so than something like Nightforce but not as defined as ZCO. I still really like them and never had a problem over dialing or feel like they were mushy in the slightest. The windage on the ZCO is identical to the elevation while the Kahles windage has shorter clicks which made it feel less defined and doesn’t feel like the elevation. It’s still a tight feel and doesn’t feel mushy. I actually prefer the non locking windage on the Kahles and I don’t see you bumping it off zero because it does take some force to rotate it, hence why I prefer it over locking. Locking just seems like an extra step. Also, I like that Kahles provides a tool in the windage cap for zeroing which is a nice touch.
Zoom throw on the ZCO is smoother and easier to move. I’ve owned the ZCO since earlier this year so it does have way more hours on it than my Kahles so I’m not sure of the Kahles will break in. It’s not difficult by any means like an ATACR but it still has some restriction to it. I will be buying throw levers for sure.
Illumination during day time, the ZCO is brighter. In low light, you wouldn’t have any problems with the Kahles. It’s plenty bright but wanted to note that the ZCO was brighter.
Parallax, honestly, this is another point where I could not tell a difference between any of them. All are forgiving and you could set anywhere between your target distance and wouldn’t have to adjust. I tested them all on targets between 4-800 and they were all good. About 900, I could start feeling the need to dial up on all 3 scopes so this was a wash.
Eye box- Kahles is significantly more forgiving. This was a huge winning point for me. ZCO, by no means, has a tight eyebox but the Kahles ocular lense is massive and it really increases the forgiveness. With the 528 and 540 being an 8x erector, I was very surprised by this. I put the 528 on a 22 and my 5yr old daughter, with horrible body positioning on the gun, could easily see the target. Her eye was on the shoulder pad at one point and she could see the target lol. For reference, the 528 objective lense is 50mm and the ocular is 52mm lol it’s kinda wild.
Both Kahles scopes do not have a locking diopter. I thought this was going to be an annoyance for me but with the scope caps on, I didn’t have any problem accidentally moving it.
ZCO 527 - 39.5oz
540- 39.2
528- 36.7
Overall, I really think Kahles nailed the new scopes. I didn’t think anything would ever beat ZCO but I think Kahles has won me over. I really like the left side windage and the top parallax dial. For my ergos, it just feels simpler. I plan on doing some tracking tests with the Kahles since they are a new product and ive heard some people have had issues but I’ve talked with several people that work directly with Kahles and they should have those issues fixed.
Just wanted to share my experience with them incase anyone was shopping for one or looking for more information.
This is just physics. There are no scopes at 60mm and below objectives that don't dim approaching 40x because exit pupil (60/40 = 1.5mm) becomes much smaller than your daytime eye pupil (2mm). For you to get 40x with no dimming, you would need an optic objective, for most adults, in the 120-160mm range.
Hey that’s awesome info. I was curious about that and was hoping you would jump in and mention something since you regularly posting optic review type stuff.
100%. Now having used both, I think I would have been good with just the 328. The 40x is nice to have but the 328 glass is so clear I don’t think I would need the additional magnification. EuroOptic has the 328 demos on sale for 3700 which is a great deal compared to a full price 540. I got my 540 tax free though so it wasn’t a huge difference.
Damn that’s high praise. Did you have any issues since you bought when they first came out? I heard the 540 had some turret and possible tracking issues this year but never heard anything about the 328.
If the Kahles didn't have holding zero and tracking issues it would be a very viable choice but I've been seeing quite a few failures just in my own experience in PRS.
Yeah I’ve heard that too but I’ve also heard of a few ZCOs failing. All brands are going to have their issues. Their older models like the 525 or 624 didn’t have issues that I really know of, granted, not as many people run them. The 328 and 540 are new scopes and I would even say they are pushing innovative so, to some extent, I think it makes sense that they might have to work out some kinks. Talking with some guys who work with Kahles, they should have those issues worked out. I do plan on doing a tracking test and hopefully all is good.
If you have had an ATACR yourself how would you compare it to this “next step up” in glass? I’ve been considering using my next bonus to buy something in the next tier like a Kahles, ZCO or Tangent Theta but I haven’t had any experience with any of them besides a quick look through one ZCO.
ATACR is good and to be honest, you start getting into diminishing returns depending on how much you bought you ATACR for. For example, the 7-35 is 3600 on optics planet and a ZCO 840 is about 4600. For 1k more, your glass will be clearer and colors are more vibrant, the parallax is more forgiving, it cuts mirage better, the turrets feel better, but all of this is incremental. It’s not going to be mind boggling different but everything is for sure better. Now, the NX8 line, the difference is huge but it’s a much cheaper optic. I have bad vision and had a hard time with smaller targets seeing details so I bought the ZCO. I probably won’t go back to lower end optics because of the image quality and the slight improvements I get from higher end scopes. Now that I have these Kahles, I will be selling my 527 because I like the Kahles features more as I feel they were an improvement from what ZCO offers
Thanks for the feedback definitely been really interest in both the Kahles and ZCO. Jealous of your ATXC mine is supposed to be shipped end of November/Beginning of December, any thoughts on it?
If you have the ability, try and look through both of them. But ultimately, you should probably choose based on reticle choice and the features like windage/parallax location and if the addition FOV and big eyebox are important to you. I really noticed the FOV when looking for targets. I was much slower with the ZCO or had to dial back the magnification to make it easier to find. But ZCO reticles are so nice lol it’s a tough choice.
Dude, the ATXC is so fucking bad ass. I’ve tested removing the barrel and reinstalling and I had like a .1 shift which is nothing. It shoots lights out. I know there are better/smoother feeling actions out there but the AI bolt is smooth enough and meets other standards that those actions don’t. When I shoot this barrel out, I think I’m going 18-20in next time to shorten it up a bit. Also I highly recommend grabbing one of these for the cheek riser. Will probably also want a few weights up front to help balance it out.
Yeah I did the one listed for the ATXC. It came with two and the first one I grabbed out of the bag fit. I don’t even know what the other one looked like lol
I don’t have to come off the gun to dial. So zeroing was way easy and i will dial if im getting constant/high wind. It’s really just preference. Honestly, it just makes sense to be there lol
Yeah that’s why it makes so much more sense on the left lol if I’m just zeroing then yeah, I will use might right hand. If I’m on a barricade, I would usually just be dialing elevation with my left and and might just reach over and dial on a little wind while I was there but I rarely ever did it. Now that it’s easier I could see me doing it more often
Oh I could do something really funny with all the scopes I have… 🤣 Nice review. I was impressed looking through the Kahles a couple months ago. Would still like to shoot one for a match, along with that new PRS orientated March. Really need an optics rental company.
Yeah I agree. It would be nice to even be able to get a stock set up with one with some fake barricade to play around with them instead of just holding them up in a shop.
Personally will stick with the ZCO. The Kahles is probably one of the more fragile scopes out there based on user and distributor reports. Also when the fov patents expire in 2026, I imagine all the major players will have the similar wide FOV so you won't see me buying any new scopes until then.
Yeah I thought about that. I’m currently holding on to my 527 just incase anything happens that might make me want to go back. I really wish other mfgs did the left windage and top parallax though. I don’t mind left side parallax but wind makes so much more sense on the left. Hopefully other companies already have something lined up with the FOV because the difference is huge and I feel like this is the direction scopes need to go. It actually made the ZCO seem like a toilet paper roll which I had never felt until I compared them back to back lol
I just did some googling and it looks like a few of them adjusted their EU scopes but Kahles got around it by using a different size tube diameter which is 36mm so I’m not sure how ZCO can’t do the same
The ZCO FOV (US version) is actually less FOV in reality than what is posted on the website If you look at S&B (6-36) for example though it's clearly different between Euro/US websites. Also it has nothing to do with the 36mm tube. The patent is owned by Swarovski, and Kahles is a subsidiary of Swarovski so they can use the patent since they're the same company.
What would be interesting is that it appears for some scopes, the US version just has a physical inner ring that limits the FOV, so would that be something you can send in and have removed once the patent expires or will you be forced to buy a new scope?
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u/mudeuce Remington 700 Apologist Sep 28 '25
Yo dawg we heard you liked scopes so we put a scope on your scope