ZeroTech Thrive X 3-9×40: A Budget Scope With a BDC Dial

Last updated October 2026 · By Nick Hall, who covers hunting optics and budget riflescopes for USA Gun Shop readers

Quick take: ZeroTech Optics USA has introduced the Thrive X 3-9×40, a second focal plane hunting scope sold in four reticle versions. Regular prices are $299 for the Zeroplex model and $349 for the three that ship with an adjustable BDC turret. It is a plain deer-rifle scope with one useful trick on top.

• What it is: Four 3-9×40 second focal plane riflescopes on a 30mm tube, sold as the Zeroplex (THX3940), G4 (THXB3940G), PHR 3 (THXB3940P3) and PHR 4 (THXB3940P4).
• Price: ZeroTech lists regular prices of $299 for the Zeroplex and $349 for the other three, with a store sale at $219 and $299 when we checked on October 26, 2026.
• Where: All four showed as in stock on ZeroTech’s own online store, where the product pages went up on October 23.
• Why it matters: The G4, PHR 3 and PHR 4 models carry five lockable distance markers that you set from your own rifle and load instead of factory numbers.

Most budget 3-9×40 scopes are the same scope. Duplex reticle, capped turrets, fixed parallax and nothing to argue about. ZeroTech kept most of that recipe and changed the one part hunters end up fiddling with after their first trip to the range.

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What ZeroTech Put in the Thrive X 3-9×40

ZeroTech Optics USA announced the Thrive X 3-9×40 line on October 26, 2026. The product pages had already gone up on ZeroTech’s store three days earlier, on October 23, so the scopes were quietly for sale before the announcement.

All four versions share one optical package. That means 3-9x magnification, a 40mm objective, a 30mm 6061-T6 aluminum maintube and fully multi-coated lenses, with a field of view of 37.7 feet at 100 yards on 3x and 12.6 feet on 9x.

Eye relief is 3.3 inches. The turrets click in 0.25 MOA with 60 MOA of internal travel in both elevation and windage, the parallax is fixed at 100 meters (109 yards), and the scope carries an IPX7 waterproof rating. There is a locking diopter, but no illumination and no zero stop.

The pitch on the Thrive X 3-9×40 PHR 4 page is refreshingly low-key: “The best sign of a scope that suits you is how little you think about it.” For a deer scope, that is the right goal.

The Adjustable BDC Turret Is the Whole Pitch

The G4, PHR 3 and PHR 4 models wear what ZeroTech calls the Adjustable BDC Turret. It carries five reference markers on the elevation dial, and each one locks on its own.

ZeroTech’s own FAQ puts it simply: “The markers are set at the range rather than at the factory.” You zero the rifle, shoot at each distance you want marked, then move a marker to that spot and lock it. The full 0.25 MOA scale stays readable underneath, so the turret still works as a normal dial whether you set the markers or not.

That solves the problem with a classic BDC turret, which is engraved for one assumed cartridge and velocity and starts lying to you the moment your rifle, your barrel or your favorite factory load does not match the numbers the factory guessed, and anyone who has switched from one 150-grain load to another before deer season knows how fast that adds up.

But it is still a dial with five marks, not a ballistic solver. Your markers are only as good as the shooting you did to set them, at the conditions you set them in.

The BDC models also come with a standard turret dial and cap, a 1.5mm hex key and three spare grub screws for the BDC turret. If you would rather run plain MOA clicks on one rifle, you can.

Four Reticles, One Scope

The reticle is the only real choice here, and it decides the price. The Zeroplex model skips the BDC turret and weighs 18.4 ounces. ZeroTech sums it up as “A favorite reticle for shooters of all disciplines where speed and simplicity is key.”

The other three weigh 18.8 ounces including the BDC turret. The G4 adds holdover references at 44 and 22 MOA plus fine 0.7 and 0.2 MOA marks, the PHR 3 is a simplified version of ZeroTech’s PHR 2 layout, and the PHR 4 pairs a floating center dot and cross with heavy outer bars at 3 and 9 o’clock and an open upper field.

Remember that this is a second focal plane scope, and ZeroTech calibrates the reticles at 9x. Any holdover mark reads true only at 9x, which is the trade every SFP hunting scope makes. Our first focal plane vs second focal plane explainer walks through why that matters.

Price, Stock and the Bigger Thrive X Family

ZeroTech’s store shows the Thrive X 3-9×40 Zeroplex with an original price of $299 and the G4, PHR 3 and PHR 4 at $349 each. When we checked on October 26, all four were in stock and on sale, at $219 for the Zeroplex and $299 for the BDC models. Store sales end, so treat those numbers as a snapshot.

Every Thrive X 3-9×40 is covered by ZeroTech’s Triple-A Lifetime Warranty. ZeroTech says it is fully transferable, with no paperwork and no receipt required.

The 3-9×40 is not the whole Thrive X line, either. ZeroTech’s Thrive X category also lists 3-12×44 and 4-16×50 models in Zeroplex, Mildot, G4, PHR 3 and PHR 4, starting at regular prices of $329 and $399, and both of those bigger scopes get parallax that adjusts from 10 yards to infinity.

That puts the whole family well inside the price range of our best rifle scopes under $500 list, which is where it will have to earn its place.

Who Should Buy the Thrive X 3-9×40

This scope suits a standard-weight bolt-action deer rifle, the kind of rifle that fills most of our best deer hunting rifles list. You will need 30mm rings with enough height to clear the 51.5mm objective bell, and an 18.8-ounce scope is no featherweight on a mountain rifle.

If you hunt timber and stands where shots stay close, the $299 Zeroplex does the job and the BDC turret is money you do not need to spend. If you shoot one load across fields and cut lines and want quick holds past 200 yards, the BDC models are worth the extra $50 at regular price.

What no spec sheet tells you is how the glass looks at last light, or whether the markers hold after a season of bouncing around in a truck. Those two things decide whether a budget scope is a bargain.

Zero it. Mark your distances. Then stop thinking about the scope.

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Frequently Asked Questions

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• Best Rifle Scopes Under $500: Tested and Ranked
• Best Rifle Scopes for Hunting and Long Range
• First Focal Plane vs Second Focal Plane Explained
• How to Sight In a Rifle Scope: Step by Step
• Best Scope Rings and Mounts
• Best Deer Hunting Rifles