Pillar guide
The Rimfire Rifle Guide: Bolt, Semi-Auto & Lever — and What Ammo Each Wants
Almost every rimfire accuracy problem people blame on ammunition is really a mismatch between the ammunition and the action feeding it. Pick the action first, then let the action tell you what to feed it — not the other way around.
The short version
- The action decides the ammo. A bolt gun will digest anything from subsonic target loads to hypervelocity; a blowback semi-auto needs enough pressure to cycle and will choke below it.
- Semi-autos are not less accurate by design — they are less tolerant. The chamber is cut longer to feed reliably, and that free travel is where consistency goes.
- Buy the rifle for the job, then spend the ammo budget on testing. Rimfire is lot-sensitive in a way centerfire simply is not.
- 1:16 twist is the .22 LR standard and there is almost never a reason to chase anything else. The .17 rimfires are the exception, and they are a different platform conversation entirely.
Why the action comes first
Centerfire shooters get to think about ammunition as a variable they control. They can change the powder charge, the bullet, the seating depth, the primer. Rimfire shooters control exactly one thing: which box they buy. The cartridge has been fixed since 1887 in the case of the .22 Long Rifle, the priming compound is smeared inside the rim at the factory, and there is no handloading it in any practical sense.
That single constraint reorganises everything. In centerfire, you tune the load to the rifle. In rimfire, you tune the rifle purchase to the ammunition you can actually get, and then you test lots until you find one your barrel likes. Which means the action type — the thing that determines what the rifle will reliably feed, extract and eject — is not a preference. It is the first and largest filter on your ammunition options.
Get this backwards and you produce the single most common rimfire complaint on every forum: someone buys a semi-automatic, feeds it quiet subsonic ammunition because it was cheap or because they wanted it quiet, and then concludes the rifle is broken when it short-strokes every third round. The rifle is fine. The pairing was never going to work.
Bolt actions
The bolt action is the default answer for anyone whose primary interest is hitting small things at distance, and it is the default answer for a reason that has nothing to do with mystique. A manually operated bolt does not need the cartridge to do any work beyond launching the bullet. It extracts because you pull it. That means the rifle imposes no lower pressure limit at all, and the entire ammunition catalogue — from the quietest subsonic target load to the fastest hypervelocity varmint round — is available to you.
It also means the chamber can be cut tight. There is no feeding compromise to make, because you are the feeding mechanism, and a tight chamber is where rimfire accuracy comes from. A bolt gun with a match chamber and a barrel that likes a particular lot of match ammunition will do things that genuinely surprise people who have only shot centerfire.
What bolt guns are good at
- Total ammunition freedom. Subsonic, standard, high velocity, and the .17 and .22 magnum rimfires all work in a bolt platform designed for them.
- Suppressor pairing. If quiet is the goal, subsonic ammunition and a manual action are the combination that actually delivers it. A semi-auto adds mechanical noise the can cannot silence.
- Precision disciplines. Every serious rimfire precision series is dominated by bolt guns, and the equipment lists reflect it.
- Longevity. Fewer parts under stress, simpler to clean, and the platform tolerates neglect better than a blowback action clogged with lead and unburnt powder.
Where bolt guns cost you
Rate of fire, obviously, and that matters more than enthusiasts admit. If the purpose is teaching a new shooter, plinking with friends, or running a rimfire steel-plate discipline against a clock, working a bolt between every shot changes the character of the day. There is also a real ergonomic issue in the budget tier: cheap rimfire bolt actions frequently ship with gritty triggers and stocks that fit nobody, and the fix costs more than the accuracy gain from a better barrel would have.
The other cost is subtler. A bolt gun that will shoot well with the right lot of ammunition will shoot indifferently with the wrong one, and the gap is wide enough to be demoralising. Buying a precision-capable rimfire and feeding it bulk-pack high-velocity ammunition is a common and expensive mistake — you have paid for capability you are actively preventing the rifle from expressing.
Semi-autos and the cycling floor
Virtually every rimfire semi-automatic in circulation uses simple blowback operation. There is no gas system, no locking lug rotating out of battery. The bolt is held shut by nothing but its own mass and spring pressure, and the cartridge's own chamber pressure pushes it rearward. It is elegant, cheap to manufacture, and reliable within a defined window.
That window is the whole story. The bolt mass and recoil spring are chosen at the factory around a pressure assumption — in practice, around standard high-velocity .22 LR. Feed the rifle something meaningfully weaker and the bolt does not travel far enough back to pick up the next round. You get failures to eject, failures to feed, stovepipes, and a shooter who thinks the gun is defective.
This is the most-asked rimfire question there is, so here is the direct answer: most blowback semi-autos will not reliably cycle subsonic or true standard-velocity ammunition out of the box. Some will, some will with a lighter recoil spring or a lightened bolt, and some never will. If your goal is a quiet suppressed rimfire, a bolt action removes the problem entirely rather than engineering around it. If you want a semi-auto to run subsonic, treat it as a project with a real chance of failure, not a purchase.
The accuracy question, answered honestly
Semi-autos are not inherently inaccurate. What they are is built to feed, and feeding requires tolerances that work against consistency. The chamber throat is longer so a round stripped from a magazine at speed will chamber even if it is presented imperfectly. The bullet therefore travels further before the rifling grips it, and that unsupported travel is where variation is introduced. The action is also still in motion while the bullet is in the barrel, which is a source of vibration a locked bolt does not have.
The result is that a good semi-auto shoots respectably and a great one shoots well, but the ceiling is lower and the ammunition sensitivity is different in kind. Bolt guns are picky about which good ammunition they prefer. Semi-autos are picky about whether the ammunition works at all.
Where semi-autos win outright
- Volume shooting. Plinking, informal practice, and any session where the point is trigger time rather than group size.
- Timed disciplines. Steel-plate rimfire games are built around semi-autos and the sport is far less rewarding without one.
- New shooters. Removing the manual action removes a step, and the step is where beginners disturb the rifle.
- Aftermarket depth. The dominant American rimfire semi-auto platform has a parts ecosystem rivalling the AR-15 — triggers, barrels, stocks, receivers, everything.
The maintenance burden is real, though, and under-discussed. Blowback actions vent a lot of unburnt powder and lead residue directly back into the receiver. A semi-auto that has fired a few thousand rounds without cleaning will start producing failures that get misattributed to the ammunition. Rimfire ammunition is dirty by design; the lubricated lead bullet leaves wax and lead in the bore and the priming compound leaves residue everywhere.
Lever and pump actions
Lever-action and pump-action rimfires occupy a category that is part practical and part deeply enjoyable, and it would be dishonest to pretend the second part is not most of the appeal.
Mechanically, both share the bolt gun's great advantage: they are manually operated, so there is no cycling floor. A lever .22 will shoot subsonic ammunition all day. Many will also feed .22 Short, Long and Long Rifle interchangeably from a tubular magazine, which is a genuinely useful trait that no detachable-box rifle offers and which makes the quietest possible practice loads viable.
The tubular magazine is also the main constraint. Loading is slower and fiddlier than a box magazine, capacity is high but the tube must be topped up round by round, and the design does not lend itself to the kind of quick reload a timed discipline demands. Accuracy is generally sporting-grade rather than precision-grade, partly because of the chambers and partly because the barrel is not free-floated in most designs — the magazine tube is hanging off it.
Pump-action rimfires are rarer, cycle faster than a lever for most shooters once practised, and were historically the gallery-shooting platform of choice. They share the lever's tube-magazine flexibility and its accuracy ceiling. If you want one, you almost certainly already know you want one, and that is a perfectly good reason.
Single-shots and youth rifles
The single-shot bolt or falling-block rimfire is the most underrated rifle in the category. For teaching, it is not merely adequate, it is better: a rifle that physically cannot fire a second round without a deliberate loading action removes an entire class of new-shooter accident and forces the deliberateness that good marksmanship is built on.
Youth-sized rifles deserve a specific mention because the sizing is not marketing. A rifle too long in the length of pull forces a new shooter into a head position they cannot repeat, and inconsistent cheek weld produces inconsistent hits, which produces frustration and a shooter who decides they are bad at this. Many current youth models ship with spacer systems so the stock grows with the shooter, which is the feature to look for rather than simply buying short.
Chambers, throats and why your rifle is picky
Two rimfire rifles with the same barrel length and the same twist rate can shoot the same box of ammunition to noticeably different standards, and the usual reason is the chamber — specifically the throat, the short unrifled section the bullet crosses between leaving the case and engaging the rifling.
A sporting chamber is cut generously so that any ammunition from any manufacturer, including out-of-spec bulk-pack, will chamber without drama. It is the correct choice for a rifle that will eat whatever is on sale. The cost is that the bullet gets a running start before the rifling straightens it out, and it may not enter the bore perfectly aligned.
A match chamber is cut to minimum dimensions. The bullet is supported and aligned essentially from the moment it moves. This is where rimfire precision lives, and it is also why a match-chambered rifle can be genuinely fussy about ammunition that is slightly oversized — some bulk ammunition will chamber stiffly or not at all.
The Bentz chamber was developed as the semi-automatic compromise. It is tighter than sporting but has enough relief to allow a round stripped from a magazine under spring pressure to seat reliably. Most quality match-grade semi-automatic barrels use it, and it is the reason a good aftermarket barrel transforms a semi-auto more than almost any other single part.
The practical consequence for a buyer: if you intend to shoot bulk ammunition, a tight chamber is a liability rather than an asset. If you intend to shoot match ammunition and chase groups, a sporting chamber will cap your results no matter what you feed it. Decide which shooter you are before you spend money.
Twist rate and barrel length
Rimfire twist rate is one of the few areas where the industry has genuinely settled and the internet has not noticed. One turn in sixteen inches is the .22 Long Rifle standard, it has been for a very long time, and it is correct for the bullet weights the cartridge actually uses. Faster twists exist and are occasionally marketed for heavy subsonic bullets, but the practical gains are small and inconsistent, and no serious rimfire discipline has moved away from the standard.
Barrel length is more interesting and more counterintuitive. Because .22 LR uses a fast-burning powder charge in a tiny case, the powder is essentially finished doing useful work well before the muzzle of a typical rifle barrel. Past a certain point, additional barrel length adds friction without adding velocity, and velocity can actually decrease in very long barrels. This is the opposite of the centerfire intuition, where longer generally means faster.
What that means in practice is that short rimfire barrels are not the compromise people assume. A carbine-length rimfire barrel gives up far less velocity than a centerfire shooter would expect, handles better, and is markedly more pleasant with a suppressor hanging off the end. The one thing a longer barrel reliably buys is a longer sight radius for iron sights, which matters enormously for smallbore target disciplines and not at all for a scoped rifle.
.22 LR vs .22 WMR vs .17 HMR
These three are not interchangeable, and the differences are more about platform than about ballistics.
.22 LR is the entire reason the category exists. It is by a wide margin the cheapest centerfire-or-rimfire cartridge to shoot, the ammunition selection is enormous, every action type is available, and the recoil and noise are low enough that it is the correct first rifle for essentially everyone. It is also the only one of the three with a serious subsonic and suppressed ecosystem, because it is the only one whose standard loadings sit near or below the sound barrier to begin with.
.22 WMR — .22 Magnum — is a longer, higher-pressure case that requires its own dedicated firearm; it cannot be fired in a .22 LR chamber and attempting it is dangerous. It extends useful range meaningfully over .22 LR and hits harder at distance, at a per-round cost that is several times higher. Semi-automatic .22 WMR rifles exist but the higher pressure makes simple blowback marginal, and the platform has historically had more reliability trouble than .22 LR semi-autos.
.17 HMR is a .22 WMR case necked down to take a .17 calibre bullet, and it flies flat enough to change how you aim. Where .22 LR demands genuine holdover past a hundred yards, .17 HMR shoots a much flatter trajectory over practical varmint distances. The trade-offs are a per-round cost comparable to or above .22 WMR, a much lighter bullet that wind can push around more than the flat trajectory would suggest, and a twist rate around one in nine to stabilise the smaller bullet. It is a bolt-action cartridge in practice; semi-autos exist but the platform has never been trouble-free.
The matching table
This is the summary to work from. It is deliberately about compatibility and intent rather than about brand names, because the right brand is whichever lot your specific barrel happens to like, and no table can tell you that.
| Action | Ammo it wants | Ammo to avoid | Best suited to |
|---|---|---|---|
| Bolt | Anything. Match and standard velocity for groups; subsonic for suppressed | Nothing mechanically — but bulk high-velocity wastes a match chamber | Precision, hunting, suppressed work, teaching |
| Semi-auto (blowback) | High velocity, or standard velocity if the rifle is proven to cycle it | Subsonic and most true standard-velocity target loads | Plinking, volume practice, timed steel disciplines |
| Lever | High velocity and standard; tube magazines often take Short and Long too | Nothing mechanically; pointed bullets in a tube magazine | Field carry, informal shooting, small game |
| Pump | As lever — wide tolerance, tube magazine flexibility | Pointed bullets in a tube magazine | Fast manual repeat fire, gallery-style shooting |
| Single-shot | Anything, including the quietest loads made | Nothing | Teaching, disciplined practice, minimal-noise pest control |
In a tubular magazine, cartridges sit nose to primer. A pointed bullet resting against the rim of the round in front of it is a hazard under recoil. This is why tube-fed rimfires are loaded with round-nose or flat-point ammunition, and it is a real safety rule rather than a traditionalist preference. Check the manufacturer's manual for your specific rifle before loading anything unusual.
Buying: new, used and what to check
Rimfire rifles hold up extremely well. The pressures are low, the steel is not being stressed, and a rifle from decades ago that has been kept dry is frequently a better buy than a new budget model. The used market is where the value is, provided you know what to look at.
Check the crown first
The muzzle crown is the last thing touching the bullet and any nick, burr or uneven wear there will open groups more than almost any other single defect. Look at it directly in good light. Rimfire crowns get damaged by cleaning rods pushed carelessly from the muzzle, which is common on older rifles cleaned before rod guides were standard practice.
Then the bore
Rimfire bores can look filthy and shoot beautifully — a layer of lead and wax is normal and some rifles genuinely prefer a slightly fouled bore. What you are actually looking for is pitting from corrosive ammunition or long-term moisture, and bulges. Dirt cleans; pitting does not.
Then the trigger and the fit
A gritty, heavy trigger is the single biggest limiter on a new shooter's accuracy and on the enjoyment of an experienced one. Many current rimfire rifles ship with adjustable triggers that are genuinely good, and many older ones can be improved cheaply. Factor the cost in if the trigger is bad, and be honest about whether the stock fits the person who will actually shoot it.
Then the magazines
Magazines are the most common failure point on any rimfire semi-auto and the hardest part to source for discontinued models. Before buying a used rifle, check that magazines are still made. A rifle with unobtainable magazines is a wall hanger no matter how nicely it shoots. Buy spares when you buy the rifle, not later.
Budget the ammunition testing
The last piece of advice is the one most often skipped. Rimfire barrels have preferences that are specific to the barrel and often specific to the production lot, not merely the brand. Buying one box each of several different loads and shooting them in a controlled way over a single session will tell you more about your rifle than any review will, and when you find the one it likes, buy that lot in depth while it is still available. That last part is the whole reason experienced rimfire shooters buy ammunition by the case rather than the box.
Frequently asked questions
Can I shoot .22 LR in a .22 Magnum rifle?
No. The .22 WMR case is longer and larger in diameter and operates at much higher pressure. A .22 LR round fired in a .22 WMR chamber is unsupported and can rupture. The two cartridges require separate firearms, and the only exception is a rifle sold with a dedicated interchangeable cylinder or bolt assembly specifically designed by the manufacturer for both. Check your manual, not the internet.
Why won't my semi-auto cycle subsonic ammunition?
Because blowback actions are unlocked by the cartridge's own pressure, and the bolt mass and recoil spring were chosen around high-velocity .22 LR. Subsonic loads generate less impulse, the bolt travels a shorter distance, and it may not travel far enough to eject the spent case and pick up the next round. Some rifles can be made to run subsonic with a lighter recoil spring or a lightened bolt, but it is a modification project with no guaranteed outcome. A manually operated action sidesteps the problem entirely.
Is a bolt action really more accurate than a semi-auto?
On average yes, but the mechanism matters more than the headline. A bolt action allows a tighter chamber because it does not need to feed under spring pressure, and a tighter chamber aligns the bullet with the bore sooner. The action is also locked and static while the bullet is in the barrel. A high-quality semi-auto with a match-grade Bentz-chambered barrel closes much of that gap, but it costs considerably more than the rifle it started as.
What barrel length should I get?
Shorter than instinct suggests. The .22 LR powder charge finishes its useful work well before the muzzle of a typical rifle barrel, so extra length adds weight and friction rather than velocity. A carbine-length barrel handles better and suits a suppressor far more comfortably. The one real argument for a long barrel is sight radius if you are shooting iron sights competitively.
Does twist rate matter in .22 LR?
Very little in practice. One turn in sixteen inches is the long-standing standard and it stabilises the bullet weights the cartridge actually uses. Faster twists are occasionally marketed for heavy subsonic projectiles, but no major discipline has moved away from the standard and the reported gains are inconsistent. Spend the attention on chamber quality and ammunition selection instead.
How much should I spend on my first rimfire rifle?
Less than you think, and reserve a meaningful share of the budget for ammunition testing and a decent optic. A mid-tier bolt gun with a good trigger, paired with several boxes of different ammunition so you can find what the barrel likes, will outshoot an expensive rifle fed whatever was on the shelf. If the rifle is for a young or new shooter, prioritise stock fit over everything else on the spec sheet.