KelTec PR57 - Barrel, Velocity, True Rifled Barrel Length, vs 22LR

AmbGun PR57 Page
https://www.ambgun.com/ambidextral-pistol/keltec-pr57

According to KelTec, the PR57 has a 4” barrel. Well it's a fucked up measuring system (not KelTec’s fault) that includes the chamber in the measurement…subtracting for the 5.7 cartridge, the PR57 has a true Rifled barrel length of 2.9”.

That's pretty short for the 5.7 cartridge. In contrast the P17’s 3.8” barrel, when adjusted for 22LR cartridge length is about 3.1” And my Ruger MK III has a true Rifled barrel 4.7’ long. The Walther P22Q, 2.8”. The Ruger LCP II lite rack, 2.1”. And since revolver barrel lengths are measured “properly”, the NAA Mini Revolver is true to factory specs at 1.125.

I thought, aha, maybe a longer barrel 22LR Pistol makes up for the 5.7’s powder advantage. So I headed to the range determined to prove that there was no benefit to running 5.7 out of such a short barrel when compared to 22LR. Thinking Lots of powder spent creating that muzzle flash.

Using a Garmin Xero Chrono I found…

The velocity of 40gr Mini-Mag out the P17’s barrel is 1017 fps, the Ruger kind of shocked me with a lower velocity of 995 fps, the Walther P22Q came in at 923, the Ruger LCP2 was 822 but if I ran 29 gr Punch it was 1094 fps. The tiny NAA Mini Revolver delivered 724 fps.

whereas the KelTec PR57 exits the muzzle at 1625 fps. Not exactly armor defeating but it is light cover piercing velocity. While I do not have a 22 magnum for comparison, I understand that I can expect 1300-1500 fps from that cartridge out of pistol length barrels.

In years past when 5.7 ammo was generally over $1 round, I might conclude the difference vs 22LR was not worth the price, but now that 5.7 can regularly be purchased for just 2-3 times the cost of 22LR or about the same as 9mm, things are more competitive.

5.7 was not tabulated in Greg Ellifritz’s research and was not available back when the “Handbook on Human Vulnerability” live animal tests were done. However, based upon the other pistol calibers tested, I doubt the 5.7 delivers significant real world human lethality differences over 22LR….or that it suffers in comparison to other calibers like 9mm and 45 ACP. Probably more of the “no discernible difference” as reported in “Handbook”.

5.7 benefits? Capacity. Velocity for flat shooting. Mild recoil. Reloadable and a bit more reliable than Rimfire. But you're not going to get those 5.7 touted 2,000+ fps “armor piercing” velocities out of a pistol…the PR57 or any other.

Nonetheless For mountain biking and hiking in grizzly country, I'll take the extra bit of penetration and highest rounds per size and weight of the PR57 over any 22…or even a 10mm. Still, I'd really like to see a long slide version with a real 4”, 5” or even 6” barrel.