Understanding Rimfire Rifle Cartridges Beyond The Basics
I spent years shooting .22 LR just because it was cheap and easy. Then I started actually looking at what other options existed and realized I was leaving performance on the table. Rimfire Central has been one of the most useful resources for anyone wanting to dig into rimfire ammunition beyond the standard target plinking rounds. Their content covers everything from cartridge dimensions to real-world accuracy testing. The .22 Long Rifle dominates the rimfire market, but it is not the only option that matters. Let me walk through what actually works and where the common misunderstandings are. Most people know the .22 LR. It fires a 40-grain bullet at somewhere between 1050 and 1200 feet per second depending on whether you are shooting standard velocity or high velocity ammunition. The effective range for most shooters sits around 50 to 75 yards. Beyond that, bullet drop becomes significant and the round starts losing energy fast. I have seen shooters claim 150-yard kills on varmints, but that requires exceptional aim and favorable conditions. It is not realistic for most people at a range.
The .22 WMR or Winchester Magnum Rimfire is a different animal entirely. It pushes the same 40-grain bullet much harder, typically around 1500 feet per second. That extra velocity translates to a flatter trajectory and more energy downrange. Where the .22 LR drops several inches at 75 yards, the .22 WMR stays relatively flat out to that distance. I switched to .22 WMR for varmint hunting because the terminal performance difference is noticeable. A well-placed shot at 100 yards actually takes the animal humanely instead of wounding it. Then there is the .22 Short and .22 Long. These are largely historical at this point. The .22 Short fires a 29-grain bullet at roughly 1050 feet per second and was the original Colt patent cartridge. The .22 Long is a minor step up. Both feed reliably in most guns chambered for them, but ammunition availability varies by region. I found .22 Short hard to source outside of collector circles and the performance gain over .22 LR is minimal enough that I stopped chasing it. Here is something most beginners miss. The ignition reliability of any rimfire cartridge depends heavily on the sharpness of the firing pin and the condition of the chamber. I once had a Marlin 60 that would miss-fire roughly 15 percent of the time with various brands of .22 LR. Stinging the firing pin with a fine stone and cleaning the chamber mouth with a chamber brush fixed the issue completely. The problem was not the ammunition. It was a worn firing pin tip creating inconsistent primer detonation. This happens more often than you would think with older rifles.
Cartridge overall length matters for feeding. The .22 LR has an OAL of about 1.010 inches while the .22 WMR stretches to 1.305 inches. These dimensions affect how reliably a gun feeds from its magazine. A rifle designed for .22 LR will not chamber .22 WMR and attempting to do so is dangerous. Some people have tried using adapters in older rifles. This is not recommended. The headspacing on rimfire cartridges is determined by the rim, and modifying a chamber to accept a different cartridge compromises safety. Bullet weight and construction also change how a round performs. Standard target ammunition uses a plain round nose bullet at 40 grains. Hollow point variants like the CCI Stinger or Federal Bulk Pack use a 32-grain bullet for higher velocity. I prefer the hollow points for small game hunting because the expansion creates better wound channels. The velocity numbers on the box are not always accurate either. I chronographed several boxes of supposedly standard velocity .22 LR and found the actual average came out to about 1120 fps instead of the advertised 1050 fps. Federal and CCI tend to run hotter than specifications. Winchester stays closer to listed numbers. Storage conditions affect rimfire reliability more than most shooters realize. I kept a box of .22 WMR in my truck glove compartment through a Wisconsin winter and then a Arizona summer. After about eight months, the primers in that box became unreliable. Roughly one in five rounds failed to ignite. Fresh ammunition from a climate-controlled environment performed flawlessly. If you are buying in bulk for competition or serious practice, rotate your stock. Do not buy more than you can use within a year or two.
Get the Full Details
Alternative rimfire cartridges exist but they serve niche purposes. The .17 HM2 combines elements of .17 HMR and .22 WMR to create a hybrid round with moderate velocity and a 30-grain bullet. It works in modified rifles but ammunition selection is limited. The .22 Cornet and .22 Superimposed are essentially custom or obsolete designs that hold little practical value today. If you encounter someone promoting these, understand they are experimental at best. The practical takeaway is this. Learn your specific rifle's preferences by testing multiple ammunition brands. Keep a log of which rounds cycle reliably and which ones shoot accurately in your barrel. A match grade .22 LR that costs four times as much as bulk target ammo might actually shoot tighter groups in your rifle. Or it might not. The only way to know is to test it yourself. Rimfire Central publishes detailed reviews and data that can help narrow down choices, but individual results will vary based on your specific firearm.
