Ammo That Cycles: Feeding a P17, Mark IV and Other .22 Pistols

A pistol that jams on one brand and runs on another is rarely broken. It is usually answering a question about slide weight, barrel length and bullet energy.

The pistol decides, not the brand

Search for "best ammo for a .22 pistol" and you will find a dozen confident answers that all point at different boxes. They conflict because the question is underspecified. A rimfire pistol is not one thing. It might be a heavy bull-barrel target gun with a hefty bolt, or a light polymer plinker with a barrel barely long enough to count. Both are .22 LR, and they want different cartridges.

What matters is how much energy the slide needs to cycle, and how much the cartridge supplies.

A blowback pistol has no locking mechanism. The case pushes back on the bolt as the bullet leaves, and the bolt's weight and spring determine how much push is needed to open the action. Heavy bolt and stiff spring: more energy required, but also more control over how the action behaves. Light bolt: less energy required, but a narrower window before something goes wrong.

Short barrels add a second problem. A bullet in a short barrel has less distance to accelerate, so the same cartridge generates less muzzle energy in a pistol than in a rifle. High-velocity loads exist to make up that deficit.

Four kinds of rimfire pistol

This table describes tendencies, not guarantees. Each gun's manual and a few magazines will confirm.

The light polymer case

The Kel-Tec P17 is the textbook example: a lightweight polymer pistol with a 16+1 magazine and a short threaded barrel. This is the kind of gun that benefits most from a load built to maximize energy.

Two plated high-velocity candidates are worth testing first. The Aguila Super Extra 40gr HV SP is a solid-point, round-nosed bullet, which tends to feed smoothly, and it comes in a large pack that suits a long break-in. The Aguila Super Extra 38gr HP swaps in a hollow point for a bit more small-game suitability, and it is the one to try second if the solid point runs clean. Our Aguila lineup comparison breaks down how the family differs.

If the pistol stumbles on high-velocity plated ammunition from two or three brands, the likelier cause is the gun, a magazine, or a dirty chamber, not the ammunition class. Work through the semi-auto jam checklist, which puts ammunition first and the extractor last for a reason.

The heavy target pistol case

The Ruger Mark IV Target is built around a steel-heavy bolt and a long barrel, and its users historically include bullseye shooters who prefer standard-velocity target loads for consistency. That is why this class is more tolerant: more mass, more spring, a longer barrel to extract energy from the same cartridge.

Tolerant does not mean immune. The Mark IV is still a blowback gun, still depends on a clean chamber and good magazines, and still has loads it dislikes. But the range of acceptable ammunition is wider, so you have a choice you do not have with a light polymer pistol: use cheap high-velocity plated for plinking and a standard-velocity target load for paper. Our Mark IV bullseye guide covers the target side. For a wider look at pistol roles, see best .22 pistols by role.

For comparison with its main rival in this class, see DefensiveHandgun's Mark IV vs Buck Mark piece.

Large-capacity and suppressed pistols

A quad-stack magazine like the CP33's holds 33 rounds, and every extra round in the stack is another chance for rims to overlap or a nose to catch. Magazine loading technique matters at least as much as ammunition choice there, and the CP33 guide explains it. Pair careful loading with a plated high-velocity load rather than a hollow point if you are chasing stoppages.

Suppressed pistols change the equation, because the can adds a bit of mass and back pressure that affects cycling, and subsonic ammunition adds an energy shortfall. If you plan to run suppressed, test your intended subsonic load in the pistol before relying on it. See the subsonic comparison and our piece on suppressor fouling.

A pistol ammo test that takes one trip

You do not need a chronograph. You need discipline.

1. Clean first. Start with a clean chamber, bolt face and extractor so you are testing ammunition, not fouling.
2. Pick two or three candidates. One solid-point plated high-velocity, one hollow point, one standard-velocity or subsonic if you intend to use it.
3. Number your magazines. If a stoppage follows a magazine across loads, it is the magazine.
4. Shoot at least two full magazines of each. Record any stovepipe, failure to feed, failure to eject, or failure to fire.
5. Keep the box and lot number of any load that runs well, so you can buy it again.
6. Stop if the pattern is the gun. If every load fails the same way, the load is not the problem.

Be patient with a new pistol. Many .22 pistols need a break-in period before they cycle consistently, and the manufacturer's instructions are the authority on that.

Mistakes that look like ammunition problems

A few habits send people shopping for a new load when the real culprit is elsewhere.

• Judging a pistol on its first magazine. Many new rimfire pistols settle in with use. Give the break-in the manual describes a fair run before drawing conclusions.
• Mixing loads in one magazine. If you are testing, keep a single load per magazine so a stoppage tells you something.
• Ignoring the magazine spring. Short magazines with strong springs can be stiff to load; seating the last few rounds fully matters.
• Oiling heavily before a test. Excess lubricant attracts the wax and powder residue that rimfire ammunition leaves behind. A light film is plenty.
• Skipping the cleaning. A chamber caked with residue can mimic an ammunition problem.

Choosing, in one paragraph each

If you own a light polymer pistol: start with plated high-velocity solid points, move to hollow points when it runs, and avoid standard-velocity target ammunition for general use.

If you own a heavy target pistol: use whatever your use case calls for: high-velocity plated for fun, standard-velocity target loads for accuracy.

If you own a revolver: your constraint is the manual, not the energy. Use what it permits.

Editorial note: This is an independent editorial overview built from manufacturer specifications and publicly available information. We have not performed hands-on testing of the products discussed, and nothing here is a performance guarantee. Verify specifications, compatibility and legality for your own situation.

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