The basic idea of converting an AR-15 self-loading rifle into a repeater that can be manually operated after each shot is not really new. For example, some years ago the US AR-15 manufacturer Troy Industries introduced its PAR Pump Action Rifles. The company also introduced the SAR (Side Action Rifle) models featuring a side charging handle. The German AR manufacturer Hera Arms recently announced an AR-15 that eventually became a pump action model.
But until now, AR-style pump-action rifles like these have not really been able to establish themselves in static shooting disciplines, especially with sports shooters, since the movement sequence when loading, for example, in prone position is simply too uncomfortable and awkward.
An innovation developed for the UK
The simplest form of a straight-pull rifle based on the AR platform looks like this: reloading is done by pulling the classic T-shaped charging handle at the rear of the upper receiver. Schmeisser has also exported some of these designs to Britain, because there shooting with such "Civilian Service Rifles" (CSR) is very popular. However, cycling with the original T-charging handle in different shooting positions is not exactly ergonomic and practical. In the UK, at these competitions shooting is done up to 300 meters under tight time constraints. Therefore, the gun must be quick and easy to operate in any firing position and here you don't stand a chance with an AR that is operated using the original charging handle. British shooters often use AR rifles modified from local gunsmiths in small series, in which the charging handle is directly fixed to the bolt carrier and the upper receiver is milled out accordingly. In order to get a bigger piece of the pie here, Schmeisser has developed a new AR straight-pull rifle, which was already presented at the IWA 2019, but has now been fundamentally revised once again.
Quick disassembly of straight-pull rifle bolt handle
On most AR-15 straight-pull rifles the charging handle/bolt handle directly attached to the bolt carrier can lead to some problems in practice regarding transport, cleaning/maintenance and storage. The position of the bolt handle is far away from all other controls to ensure safe and fast repeating. Therefore, such a rifle often hardly fits into the usual hard-shell transport cases made of plastic or nylon fabric. In case of a pending cleaning, the bolt handle has to be unscrewed first, so that the bolt can be removed. Due to the control protruding far to the side, the rifle also takes up unnecessarily space in the gun cabinet.
Here Schmeisser has come up with an elegant solution, because the bolt handle is simply plugged into the bolt carrier. In order to achieve maximum stability, the handle is located in the middle of the bolt carrier. The only necessary tool is an object with which the pin of the bolt handle can be pressed down and then simply pulled out. This ensures easy and quick disassembly in all situations. In the case of the bolt carrier, the designers have also taken a lot of time to redesign the operating cam. This has to be modified to guarantee an optimal loading by hand. It makes sense, since this system was never designed by Eugene Stoner for manual operation. While last year's models were based on an original "Upper Receiver" , the Schmeisser SP15 Straight Pull rifles introduced here for the first time are based on a proprietary upper receiver. All other components are the same as those of the standard Schmeisser AR-15 semi-automatic rifles.
Refined, second generation SP15
All Schmeisser rifles, and thus also the SP15 models, have undergone a modernization program based on experience. For example, the classic 90 degree safety lever on both sides of the grip has been replaced by a 45 degree safety lever, which makes operation faster and easier. However, if you prefer a 90-degree safety, you can easily convert the control as the lower receiver has milled grooves for both the 45-degree and 90-degree option. The classic T-charging handle, still present on the SP15 models but without any real function as a control, has been completely modified. It is now easier to operate from both sides and the gas is diverted away from the shooter's face, especially when using suppressors. This detail as well as the new adjustable gas block does not play a role with the protagonists of our article anyway, as no gas is needed for the gun's cycling. Last but not least, the most noticeable change in the current Schmeisser rifles is the change from KeyMod to M-LOK handguard systems. Here, the company has adapted to the market, which has been asking for corresponding fore-ends. A trend that has started after the M-LOK system has proven to be the more stable one in stress tests. The wall thickness between the KeyMod slots is significantly less and can therefore break more quickly under extreme loads.
On the shooting range with the SP15 Ultramatch and M4FL in .223
For the accuracy test the Schmeisser SP15 Ultramatch and SP15 M4FL in .223 Remington were equipped with a Falke 5-30x56 riflescope and a UTG bipod. Because the forward movement of the bolt is spring controlled, Schmeisser straight-pull models can be cycled faster than a conventional bolt-action rifle. In the time the hand still has to guide the bolt handle forward on the latter, it is already long since back on the trigger on the AR straight-pull system. Thus, the Schmeisser SP15 rifles are probably the fastest bolt-action rifles on the market. During the tests, different buffer springs were experimented with, because the lighter the recoil spring is, the easier and quicker the SP15 rifles can be manually cycled. But even here there are limits, because the spring force of a too light recoil spring is then no longer sufficient to feed the next cartridge from the magazine into the chamber. No wonder, after all: the short 10-round magazines are designed for semi-automatic guns and have a very hard spring under the follower for maximum functional reliability. With classic bolt-action rifles however, much softer magazine springs can be used.
We expected the Schmeisser SP15 Ultramatch with 20"/510 mm long heavy match barrel to perform better than the Schmeisser SP15 M4FL with 14.5"/370 mm long barrel in AR standard profile with muzzle flash hider. Thus, with eight different types of ammunition, two of which were hand-loaded, with a bullet weight range from 40 to 69 grains, we achieved two groupings below the 0.39”/10 mm mark. The 55-grain Hornady Frontier Match factory cartridge and our hand load, consisting of 26.0 grains of Lovex D073.5 and a 52-grain Sierra MatchKing bullet (*) showed no differences, because the grouping circle was 0.31”/8 mm in both cases. The calculated accuracy average of the SP15 Ultramatch was therefore a pleasing 0.62”/15.75 mm. The SP15 M4FL could not match these results. With this compact straight-line bolt-action rifle, we achieved a best grouping of 0.59”/15 mm with the aforementioned hand loads. The calculated accuracy average value here was a more modest 0.949”/24.12 mm. Since gas pressure has no influence on the function of these rifles due to their design, it is of course possible to experiment with far more loads than with the AR semi-automatic rifles and to work with completely different propellants.
Our conclusion about the Schmeisser SP15 straight-pull rifle
The manual bolt action of the Schmeisser SP15 straight-pull rifles is incredibly fast compared to conventional repeaters. With a little acclimatization, these rifles can be cycled very quickly without changing the aiming position. Workmanship, equipment and reliability leave nothing to be desired and especially the SP15 Ultramatch could also impress in terms of shooting performance. Therefore the price of 1899 euro is absolutely adequate.
Text: Stefan Perey and Michael Fischer
(*) Disclaimer: Any and all loading data found here is to be taken as reference material only! This site and it's entities bear no responsibility for the use by others of the data included here!