I really wanted a Leupold 3-9x33 EFR for HFT but found that I just couldn't get a true mil-dot, or even better, half mil-dot/TMR reticle fitted. After a lot of research and agonising I plumped on taking a gamble on the MK4. I discounted some of the higher mag LR/T models after hearing a few concerns about px error. My rationale being that this would have to be re-parallaxed to a lesser degree hoping that working closer to it's design specs would possibly give less error. To be fair I took a blind punt and hoped for the best. It's actually a discontinued model as the new Leupold line up includes a 2.5-8x36 and not a 3-9. How much difference there is between them I don't know but suspect that it may just be a renaming of the same scope.
I have had the scope about a month now and am confident enough to comment on many aspects of the scope but not all. Depth of field is phenomenal. Sadly the scope is not PA adjustable (If it had this feature I suspect that there may not be many better HFT scopes) so it needed to be re-parallaxed. This turned out to be very easy. Baby boas made short work of the very lightly loctited locking ring. It cracked with bare minimum pressure.
I have had fun and games trying to establish the optimum setting for the px. I can get 8-35 yards but it leaves 45 distinctly blurry. In the end I plumped for further which gives me 13-50+ yards as perfectly usable. I went for this compromise as I like doing the long range HFT as you find at events like the DWB Anglo-American. Below 13 yard targets are acceptable naturally getting worse the closer they get. I'm still confident that I can make out a kill zone on an 8 yard target.
Optical quality is naturally very good. I didn't really appreciate how much better than the norm a Leupold would be until I spent some serious time with it. I'm a little perturbed that I'm going to end up dissatisfied with some of my cheaper scopes after using the Leupold.
The reticle is a TMR, Tactical Milling Reticle, basically the Leupold name for a half mil-dot ret. Labelling it as mil-dot isn't strictly accurate as it does not feature dots at all, just lines of different widths. Full size lines indicate a full mil-radian increment and half width mark the half mil-radian points. I've found that this is making bracketing a much more accurate affair. One thing I am finding a little strange is that the centre point of the reticle doesn't actually coincide in the familiar cross hair style. It is a little disconcerting in use after so many years using scopes that do come to a very definite central point. One potential advantage I can see in this arrangement is that your target isn't ever obscured. It makes for easier paper zeroing sessions.
A negative point (can also be a positive point when it comes to accurate bracketing) that I have already noticed with this reticle is that it's very fine. Where you are looking at targets with excellent clarity this isn't an issue. As you push the range, especially in difficult lighting conditions, it can be a little awkward discerning some of the markings. I suspect that practise, familiarity or possibly fine tuning the px setting may minimise this minor quibble. At the moment I'm not finding the reticle as easy or instant in use as I previously have with mil-dots. Again, I suspect that familiarity and practise will pay dividends in this respect.
As far as build quality is concerned, it's a Leupold, I expect it to be good and thankfully it is. Mechanicals are smooth and positive and it appears to be built to last.
The only aspect of this scope of which I'm not entirely certain as yet is the dreaded px error. I have shot with it in competition and did horrendously badly. Sadly I can't define if the scope was at fault. I can say with certainty that the owner most definitely was as my windage was found to be out by a good 9 clicks. I'm shocked that I managed to hit anything! The rifle also ended up in pieces after the event for the tender ministrations of Scooby. (thanks Pete) I knew it was a bad idea to compete with a new rifle, new scope and new pellets in one hit, especially as my usual rig was sitting unused and unloved in the boot of the car! To this end I can't really comment on the px error in use. I'm only noticing the hint of px error at the closest ranges where I'm never entirely sure about the precise spot I'm shooting at anyway. Hopefully I'll be able to nail this issue in the coming weeks but so far it's not obviously worse that any other scope I've encountered.

In conclusion, will it improve my scores? I seriously doubt it, I simply make too many errors and don't practise enough to seriously compete with the best. As I've already commented I suspect that my rangefinding will improve marginally. Is it better than many of the alternatives? Maybe, but it's probably too expensive and too awkward to procure for most to bother. Is it perfect? Almost definitely not, but until a US or German company renowned for superb optics makes a scope that is genuinely intended to fulfil the criteria of HFT or the Chinese get up to speed with their optics, I doubt perfect will be attainable. Even when this does happen you can guarantee that no one will agree anyway! As it stands it's floating my boat so far, I'll happily conceded that this position may change in time.

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