Rifle Review: Merkel RX Helix Explorer

Need one gun to do everything? Merkel's straight-pull RX Helix Explorer is built for speed — it's quick-shooting and allows you to change calibers quickly.
Rifle Review: Merkel RX Helix Explorer

Merkel’s RX Helix is a German-made bolt-action rifle for the 21st century that’s all about speed in two areas — how quickly you can work the bolt, and how quickly you can change the caliber. Desire for both those features is traced to Merkel’s roots in Europe, where game is frequently taken on drives where a quick second or follow-up shot is often offered, and where gun laws often make it more practical to own one do-it-all rifle instead of several. Americans tend to hunt game differently, and we exercise our right to own guns by owning many of them, but still the Helix has a lot to offer whitetail hunters — particularly ones who want to stay on the cutting edge of technology without sacrificing quality or falling for the folly of gimmicks.

It’s Fast

Bolt speed comes from the Helix being a straight-pull rifle, of which there have been many — both military and sporting. Just a short list includes the U.S. Lee Navy and Swiss Schmidt Rubin. Canada had the Ross. Sporting rifles include Browning’s T-Bolt, Blaser’s R93 and R8, Heym’s SR-30 and Mauser’s 96. While straight-pulls never really went anywhere for long with the military, they have had some success in the sporting market — particularly Europe. From a purely operational standpoint, straight-pulls have an advantage over turn-bolts because they reduce reloading motions from four to two, and it’s easier to cycle a straight-pull with the rifle on your shoulder because you don’t have to deal with the awkwardness of torqueing the rifle over while trying to lift the bolt handle. I don’t think a straight-pull can beat a semi-auto when it comes to firing speed, but there is an advantage in that you can make even magnum-chambered straight-pulls lighter and more compact than you can a semi.

Operating the bolt on the Helix offers a couple of mindbenders. For one, the actual distance the bolt handle travels is only 2 1/2 inches, yet the bolt carrier moves more than 4 inches. The other is that the bolt doesn’t protrude from the rear of the action when the bolt handle is pulled back fully. Both of those are possible because of a transmission gear system inside the action with a 1:2 ratio. In simpler terms, for every 1 inch the bolt handle moves, the bolt itself moves 2 inches. It moves along a helical path, hence the name “Helix,” and unlike some other straight-pulls where the bolt handle might rotate or pivot slightly to unlock the bolt lugs, the Helix’s bolt movement is only back and forth, requiring nothing more than the flick of your finger or thumb to operate. It’s really fast and surprisingly smooth and light considering all of the mechanical movement going on inside.

Multiple Personalities

Because the bolt locks directly into the barrel, the receiver isn’t stressed, so Merkel saw fit to make the receiver out of lightweight aluminum alloy and save a little weight. This rifle weighs only 6 1/2 pounds. Locking directly into the barrel also lets Merkel use one of the slickest barrel attachment features I’ve ever seen — one that doesn’t require tools and that makes the quick-change barrel feature possible. Instead of the barrel shank threading into the receiver like a conventional rifle, the shank is glass smooth except for an alignment groove and a small cam slot. The barrel is gripped and locked into the receiver by a cam lever. To change a barrel, all you have to do is push a button on the forend and pull it off, pivot down the cam lever and pull the barrel straight out.

The quick-change barrel system also works with the unique Helix bolt head to make multi-caliber changes possible. If you want to change between cartridges within the same case head family, such as .243 Win. and .308 Win., simply change barrels with the bolt open. If you want to change between cartridges with different head sizes, such as .223 Rem. and .300 Win. Mag., simply change the barrels with the bolt closed. With the bolt closed, the bolt lugs stay locked into the barrel extension and the bolt head comes right out along with the barrel. Red indicators and directional arrows make it all but impossible to install the bolt head wrong, and the alignment groove properly positions the barrel when putting it back in. The time it takes to change barrels or even calibers is measured in seconds, and about the only thing you can screw up is forgetting that you have to use a different magazine when switching between the different cartridge families.

Significant Standard Features

One standard feature I really like is that the receiver is milled with integral Picatinny bases, making it easy to add nearly any riflescope. If you’ve spent much time handling European-made rifles, you know finding a scope base can be challenging — and when you do find the right one, it’s usually very expensive. The Helix’s bases let you use commonly available Weaver-type rings, and there’s plenty of spacing between the front and rear base to accommodate most appropriately sized scopes.

Instead of a conventional safety, the Helix uses a “cock on demand” feature that lets you safely carry a chambered round with the gun uncocked, but immediately ready to go into action. It’s a popular feature on many European guns, and you see some variation of it on higher-end ones such as Blaser, Krieghoff and Steyr. Its operation is much like a familiar tang safety in that you press the thumbpiece forward to ready the gun. The difference is that you’re pushing against the pressure of the mainspring and actually cocking the gun. It takes a little getting used to, but you only have to do it for the first shot. If you choose not to shoot, pushing down on a little button in the thumbpiece and lowering it back down uncocks the rifle.

The trigger is adjustable, according to the owner’s manual, but instead of instructions it advises to have it adjusted by an authorized person. The sample I handled came set at an incredibly responsive 2-pound pull that felt much lighter.

Something you don’t see much on bolt-action deer rifles these days are iron sights. I once had an expensive Anticosti Island whitetail hunt completely sacked by a bad scope, so the irons are a feature I’ve learned to appreciate, and I lament that few guns come with them these days. The set on the Helix are set up with red front and yellow rear fiber-optic elements, helping them stand out even in low light conditions. The front sight is adjustable for elevation, while the rear is drift-adjustable for windage. They’re rugged with nothing delicate about them.


The Helix sample I received is the Explorer model chambered in 6.5x55. It differs from its Helix stablemates in that it’s basic black with a synthetic stock instead of having engraving, plating or various grades of wood as options. My first impressions were that the 1:2 ratio bolt was clever and the take-down procedure brilliant. I’m a cynic, though, and prepared myself for the whole “straight-pull being faster, easier and better than a bolt-action” thing to be nothing more than marketing hype, but I was wrong.

Equipped with a Trijicon 3-9x40mm scope, the Explorer consistently shot 1 1/2-inch groups at 100 yards using Hornady Superformance ammunition. There were no malfunctions, though primary extraction was a little bit sticky. That’s normal even with bolt guns during the summer on my range, because the conditions here are nothing short of brutal. Steady 100-degree days and baking sun quickly cause even the best lubricants to break down and pressure to rise in even the most consistent ammunition. The take-away is that I didn’t feel disadvantaged by not having the camming action of lifting a bolt handle to extract even slightly sticky cases.

Switching from a conventional bolt-action to a straight-pull reminded me of a time in my life when I switched from commuting an hour into the city to working from home. I didn’t realize the effect of the commute because it was “normal.” Likewise, lifting a bolt handle is “normal,” but once you have some trigger time with a straight-pull, you realize that lifting a bolt handle makes it harder to settle the sights back on the target. With a straight-pull you still have to recover from recoil, but because you can do that and cycle the action without ever taking the gun from your shoulder, you can get back on target much quicker.

While at the range I took the opportunity to remove and reinstall the barrel to see if there was an impact shift. There was a slight one that just reinforces the importance of checking your zero before going hunting with any gun. I didn’t have the opportunity to try barrels in different chamberings with the Explorer, but it stands to reason that you’d have to adjust your scope when changing calibers.

This is a fairly expensive rifle, but for a well-heeled traveling deer hunter who wants a unique rifle that’s eminently functional and also offers the option of multiple chambering combinations, there are thousands of dollars in potential cost advantages to the Helix over some of the other guns in its class. Chief among those savings is that you only need to buy one scope and set of rings. Other straight-pulls in this class have the scope mount to the barrel, requiring a different scope, base and rings for each. That additional cost for many chamberings can add up quickly. The trade-off with the Helix, though, is that you have to adjust your scope each time for the different chamberings.

Spec Sheet

Manufacturer: Merkel

Model: RX Helix Explorer

Calibers: .222 Rem., .223 Rem., 6.5x55 (tested), .270 Win., 7x64, .308 Win., .30-06, 8x57, 9.3x62, 7mm Rem. Mag., .300 Win. Mag.

Action: straight-pull bolt-action repeater

Magazine capacity: 3+1 (5+1 in .222 Rem. or .223 Rem.)

Barrel: 22 inches

Trigger: single-stage 2-pound pull

Sights: Adjustable green/red fiber-optic, integral Weaver bases

Stock: black synthetic

Overall length: 42 inches

Weight: 6 1/2 pounds

Other: Additional barrel assembly with sights, $1,200; Bolt, $295; five-round magazine, $150

MSRP: $3,295

For more information: www.rx-helix.com


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