It’s ironic that while most of the tri-lug rifles available here come from overseas manufacturers, European hunters -- at least those who can afford them -- prefer straight-pulls like the Merkel, Blaser and Heym. What’s really interesting is the fact that the only feature these three guns share is that they function with a simple pull-push of the bolt handle. In other words, half the movement required to load/reload a conventional bolt action, tri-lug or Mauser type. What’s amazing to me is that, unlike the 15 tri-lug rifles just discussed that share the same locking system, the actions around which these three guns are based are totally different from one another. Consider: the Blaser’s locking system consists of a thin-walled steel tube at one end of which are 13 splines or fingers if you will, each with a small bulge at the front end. Inside this tube is a tapered cone that, when pushed forward on the closing motion of the bolt, forces these splines outward so that they engage an annular groove inside the barrel extension to lock the action. Blaser refers to it as radial locking.
The Merkel RX Helix uses a multi-lug rotary lock up similar to ARs, so there’s little to expand on there. The initial rocking motion of the bolt handle rotates the bolt head out of battery, and on closing the bolt is rotated back into battery.
The Heym HR30 is yet again different from the Blaser and Merkel in that the locking “lugs” are actually 6 ball bearings seated in sockets on 60-degree centers at the head of the bolt. These sockets are slightly more than a hemisphere in depth than the diameter of the ball bearings, making them captive. Lock-up is achieved similar to the Blaser in that a cone or wedge within the bolt forces the ball bearing outward to engage an annular slot within the receiver ring. It’s hard to imagine that six ball bearings engaging an annular groove with less than a hemisphere of their bearing surface can withstand the pressures generated by high intensity cartridges, but it does.
There is no question that straight-pull actions are intrinsically more complicated, hence more expensive to manufacture. That, however, is less of a problem over there because the typical European hunter is more affluent and price just isn’t as important as it is here. Then too, we Americans are reluctant to stray from the conventional 4-stroke bolt action, because even though the ascendance of the tri-lug rifle here represents a quantum leap, there’s no difference in the way they function.
Reducing the four movements required to cycle a conventional bolt action to just a simple pull/push motion makes sense. The cocking action (uplift of the bolt handle) on a shouldered rifle is not only awkward, but the specific muscles involved are rarely used. If a fired case is even slightly sticky -- and that’s more times than not, especially where handloads are involved – cycling a shouldered rifle can range from difficult to impossible. That’s why so many hunters lower the gun to the port arms position to reload; it’s the only way they can get enough leverage to initiate primary extraction. But with a straight pull action, even young shooters have plenty of muscle power when simply pulling straight back on the bolt handle and pushing straight forward. So, not only is it twice as fast, but with the much stronger biceps being the only muscles involved, the reloading sequence is so much easier to accomplish.
If there’s a disadvantage to the straight-pull action it’s that it doesn’t have the camming force of a traditional bolt action, tri-lug or Mauser, to chamber and extract sticky rounds. That shouldn’t affect factory ammo users, and handloaders just have to be sure to fully resize their brass or use undersized dies specifically designed for semi-auto rifles.
Bottom line: Why hasn’t an American firearms manufacturer given the straight pull a shot? The only example we have is Browning’s T-Bolt, one of my all-time favorite rifles, but it can only handle rimfire chamber pressures. To come up with a manually operated rotary bolt action shouldn’t be that complicated or expensive to manufacture. Consider Remington’s Model 7600 slide action rifle; it’s simply a manually-operated version of the semi-auto Model 7400. The straight-pull rifle just makes too much sense for someone not to test the waters, sooner I hope than later. Jon R. Sundra