I’m excited about this gun: a slim, light single-stack 9mm that fits small hands really well, is very controllable, and is affordable. If it proves to be reliable as well, they’ll sell all they can possibly make for the foreseeable future.
One of the interesting things about the R-51 is that it’s not a striker-fired pistol, though it certainly resembles one. It has an internal (concealed) hammer, in the same manner of the original Model 51 (from which it takes its inspiration) and the more famous Colt Model 1903/1908.
The question many are asking is “why?”
Any handgun design is a tradeoff, and there are advantages and disadvantages to any particular aspect of the design. The major advantage of striker fired pistols has always been the low bore axis; it’s easier to design a gun that sits lower in the hand if you don’t need the vertical space for a hammer to operate. A lower bore axis means that muzzle flip is more easily controlled, which translates to being able to shoot to any given level of precision with any given level of cartridge power faster and easier.
By judiciously juggling the position of the hammer pivot and the design of the hammer itself, Remington has shown that such a design need not tremendously increase the axis height. (On the other hand SIG-Sauer, with their new P320 pistol, has shown that a striker fired gun doesn’t always have a low bore axis!)
Is there any advantage to a hammer fired pistol? It used to be thought that a hammer was more reliable, in that it could impact primers harder than a striker for any given length of firing pin travel, but the Glock (and later designs) proved that to be false.
One big advantage of the hammer is that it’s cocked by the action of the recoiling slide. This doesn’t seem like much, but it makes a big difference in the usability of the gun overall. In a striker fired design the striker is either partially or fully cocked as the slide comes back into battery. (Rifle shooters will recognize this as “cock on closing”, as opposed to a hammer-fired pistol which is “cock on opening”.)
What that means is that the striker fired gun is cocked only by the power of the recoil spring, which is working against the hammer spring. Put your hands together and push; your right hand is the striker spring, which has to be tensioned to fire, while your left hand is the recoil spring, which is tensioning that striker.
The recoil spring has to be heavy enough to not just return the slide to battery and lock the breech, but also has to overcome the counter-tension of the striker spring. The more fully the striker spring is tensioned, the heavier the recoil spring has to be. If the recoil spring gets worn, it’s possible for the gun to not return fully to battery (or, in the case of the Glock, to be pulled out of battery as the trigger tensions the striker.)
The hammer fired design doesn’t face this particular issue, because the hammer is cocked against the tension of its mainspring by the force of the slide being driven back by the cartridge. The sole job of the recoil spring is to return the slide to battery, and since it has nothing else to do can theoretically be lighter in weight, which translates to a slide that’s easier to ‘rack’. Videos I’ve seen of the R-51 in review usually mention that the slide is particularly easy to manipulate, which is exactly what the design implies. (Yes, racking the slide does require the shooter to overcome the hammer spring to get it to the cocked position, but it’s not a difficult job to contour the cam surfaces on the slide and the hammer to significantly reduce the force required.)
Striker fired guns aren’t inherently better or worse than hammer fired designs. Either can be made to be reliable, but beyond that are tradeoffs toward the designer’s goal.
-=[ Grant ]=-