In 1905, John Browning developed and introduced the 25 Automatic Colt Pistol (ACP) for chambering in the Fabrique Nationale (FN) pocket pistol of the same year. From the modern perspective, this can be classed alongside the 32 WSL as amongst the most useless cartridges ever developed. However, when it was introduced it was revolutionary. Today, the best 22 Long Rifle loads fired from similar short-barreled pistols generate as much as twice the energy of factory 25 ACP loads. The reason this weird situation exists is the low pressure used in the 25 — 17,400 psi — along with extremely limited case volume. However, when looking at the matter from the historical perspective, performance of the 25 ACP far surpassed performance of the 22 LR in the era before the modern high-velocity and hyper-velocity rimfire loads were available. The 25 has another significant advantage, the case is much stronger and the design is far more amenable to functioning well through a small semi-automatic pistol. This matters. When loaded with the Hornady 35-grain expanding bullet it can be a far better choice because the gun you have and the gun that works always beats the gun you do not have or the gun that jams. My friend, Ray Ordorika, used the Beretta tip-up barrel 25 ACP as his kill-gun on his trap lines in Alaska. Factory 50-grain FMJ bullets usually just ricocheted off the skull and merely irritated the trapped critter. So, Ray loaded rounds with the same bullets and enough RedDot to get 1000-fps at the muzzle, those bullets always penetrated and provided instant kills. He figured the gun would eventually fail but he always wore heavy leather gloves and safety glasses so he did not care about that potentiality— it was simply a tool. He sold his business to a friend who was still using his Beretta and his load decades later. While I do not recommend using such a load, it does speak to what can be done in a strong pistol chambered for the 25. As with any pistol round headspacing on the case mouth, best practice is to apply a taper-crimp after seating the bullet. This helps to lock the bullet in place against chambering forces that might otherwise drive it into the case. I cannot too-strongly recommend getting a second seating-and-crimping die so you can have one adjusted to seat the bullet and the second adjusted to only taper-crimp the case mouth. Generally, attempting to do both operations in one step is a recipe for damaged and destroyed cases.