.22 LR

About .22 LR

.22 Long Rifle is the cheapest way to shoot regularly, and regular shooting is what actually builds skill. A day of rimfire practice costs less than a box of centrefire defensive ammunition, which is why serious pistol and rifle shooters keep a .22 in the safe alongside whatever they actually carry or hunt with.

It is also the caliber most sensitive to what you feed it. Semi-automatic rimfires are notorious for running perfectly on one brand and choking on another, with no way to predict which except by testing. Rimfire priming is applied to the case rim rather than a separate primer, so the occasional dud is normal. Subsonic loads stay under about 1,100 fps and are what you want behind a rimfire suppressor.