The clever little Merkel RX Helix

A short while before visiting Miall's to handle the Mauser M03 and Blaser R8 I moved my token back to Go and ran a google search for 'German switch barrel rifle'. In amongst the list I found reference to one I hadn't heard of - the Merkel RX Helix. When I tracked one down it turned out to be a fascinating design that can't be ignored. The following links will help if unfamiliar. I fully expect you'll say 'Wow!', as I did.

Merkel's site for the RX Helix
Merkel's YouTube video showing users trying out the Helix

In summary the Merkel RX Helix is a lightweight, take-down, interchangeable barrel rifle, with a straight pull action that's geared two-to-one. The bolt moves twice the speed and distance of the bolt handle and remains enclosed in the action housing throughout its travel. The only tools needed to change calibers are a thumb and a couple of fingers, which remove the fore-stock and turn a clamping lever to set the barrel free. If the bolt is forward when this is done the bolt head comes out too, to be easily switched if required for the new barrel.

The receiver has two sections of integrated picatinny rail which don't look too inelegant. Rather, it looks purposeful and fits well with the rifle's angular, modern looks. Merkel refer to this as being a design for the 21st century and they have a point. Yet they also harken back to the well regarded philosophy of the Mauser turn bolt action, for while the Helix is a straight-pull, at the end of its stroke the bolt head rotates and its seven lugs engage with abutments in the barrel end-piece.


Merkel's design and marketing is clearly oriented to tap into concerns shooters might have about the safety and functionality of Blaser's R93/R8 locking mechanism, which does have its foibles. Merkel is not subtle in referring to the inherent safety of the rotating bolt head and how the enclosed action means the shooter does not have the experience of the bolt carrier coming back at his or her face. Nor will pieces of the bolt carrier, is their hint between the lines. Merkel are reminding their target audience that some Blasers have blown up, from reloaders using pistol powder in magnum rifle cartridges it seems - never a good idea.

Merkel also point out that the Helix's firing pin mechanism is designed to ensure that when the trigger is pulled, the rifle will fire. Here, Merkel are pointing quite openly to one of those Blaser foibles, where an R93 or R8 fed with ammo that's not sized to its liking, or even good ammo that isn't chambered with gusto, might not fire. Improper engagement of the bolt's fingers in the barrel recess causes the firing pin to be blocked, to avoid a possible case rupture. With safety in mind Blaser has made sure that its rifles won't fill my head with shrapnel, which is sure to be appreciated by the grizzly bear that is eating me. Of course Blaser owners can avoid this fate by only ever feeding their rifles with either factory ammo or properly sized reloads. And by closing the action good and hard.

Turning attention back to the Merkel RX Helix, my online research left me curious enough to drive a few hours to the nearest gun shop that had one. It was simply delightful to shoulder and aim, being lighter than a Blaser R8, though a little longer. The need for the bolt head to rotate out of the barrel together with the straight pull action's gearing meant there was a degree of inertia to overcome to get the bolt moving, but once it was moving it travelled with plenty of momentum. It was fun to use, and fast. Merkel are drawing a bit of a long bow when their marketing refers to the 1898 action as an indicator that their rotating bolt head is as safe as Mausers. They also remind us that the Merkel brothers drank beer with the Mauser brothers - but the fact is, the bearing surfaces of the Helix bolt lugs are angled and not at 90 degrees to the bore. This makes breaking the action open after firing easier, which is important given the limited mechanical advantage afforded by the straight pull. I suspect the Helix would have just as much trouble with tight reloads as the R93 or R8. Nevertheless, the pic below shows that the bolt lugs make for quite a substantial rotating lockup.

Unlike the Helix's bolt handle, the cocking slide was not so much fun. It operates in a manner similar to that of the Blasers, just a bit stiffer and trickier to manipulate. I found de-cocking to be a challenge at first - the slide has to be pushed up a little further, with the thumb then rolling forward onto the release button. The cocking slide also tended to get in the way of my thumb after operating the action and taking a new grip, but that's probably just a matter of practice. This problem is shown in the YouTube video linked above, where one of the shooters stops trying to get his thumb around the grip.

The only disappointment with the Merkel RX Helix I handled that day was the trigger. It hadn't been tuned, it was heavy and had some mushy slack before firming and releasing, with a distinct lack of crispness. I've read that Helix triggers can be nicely tuned and I'd prefer to be writing that this one had been, but alas, no. The Blaser R8 and Mauser M03 triggers I'd tried earlier were much better.

Did someone say Mauser? The salesman heard me mention "M03" and pulled a used one from the rack behind him. I couldn't help smiling as I operated the action and soon heard myself say, "This, is a proper rifle."