23-Jul-2026
Every manufacturer has one product that built the reputation the rest of the catalogue trades on. For Air Arms, that rifle is the S400. Launched at the turn of the millennium and refined steadily ever since, this single-shot PCP established the Hailsham company as a serious force in sporting airguns and remains, pound for pound, one of the smartest buys in the UK air rifle market. This review explains why a rifle with no magazine, no regulator as standard and no adjustable anything still earns a place in so many cabinets.
The appeal of simplicity
The S400 is a bolt-action, single-shot pre-charged pneumatic, available as a full-length rifle or a handy carbine, in .177 and .22. You load one pellet directly into the barrel's loading channel, close the bolt, and shoot. That is the whole system, and it is precisely the point.
A single-shot rifle has no magazine to index, no probe alignment to worry about, and no mechanism between your fingers and the pellet seating consistently in the breech. Field target and HFT shooters have always known that direct loading is the most consistent way to feed a pellet, which is why the S400's action went on to form the basis of Air Arms' competition rifles. Hunters get a different benefit: the deliberate pace of loading each shot builds the habit of making the first one count.
Build and handling
The S400 wears a well-shaped beech or walnut sporter stock with a raised cheekpiece and cut chequering, and the woodwork is finished to a standard that embarrasses some rifles costing considerably more. At around 3.2 kg bare it is noticeably lighter than its multi-shot siblings, and the carbine version is lighter and handier still, arguably the best-balanced rifle Air Arms makes and a favourite among hedgerow and farmyard shooters who carry a rifle more than they fire it.
The action is the familiar Air Arms recipe: a smooth, positive bolt, a Lothar Walther barrel, and the same excellent two-stage adjustable trigger fitted across the sporter range. Nothing about the rifle feels built to a price.
Accuracy and consistency
This is where the S400 punches hardest. With the pellet seated directly into the rifling by your thumb, and Air Arms' proven valving behind it, the S400 delivers accuracy that matches rifles at twice its price. Sub-half-inch groups at 30 yards are the expectation, not the exception, with Air Arms Diabolo Field or similar quality pellets. The firing cycle is dead, no twang, no movement, just the pellet leaving.
Shot count from the 190 to 250 bar fill (check your model's specification) runs to roughly 60 to 90 consistent shots depending on calibre and cylinder, which is less than the larger-cylinder multi-shots but ample for a hunting session or an HFT course. Aftermarket regulators are a popular and worthwhile upgrade for owners chasing chronograph-flat consistency, though the unregulated valve is already impressively stable across its sweet spot.
The S400 in the range
Think of the S-series as a ladder. The S400 is single-shot simplicity. The S410 adds the ten-shot magazine and bolt action. The S500 and S510 add the sidelever and, higher up, regulation and longer cylinders. Each step adds convenience and cost; none of them adds accuracy. That is the S400's quiet argument: the cheapest rifle in the family shoots just as straight as the flagship.
New examples typically sell for around £600 to £700 depending on furniture, with the used market offering earlier examples for considerably less. Because the design has changed so little, a well-kept fifteen-year-old S400 shoots like a current one, and parts and service from Air Arms' East Sussex factory remain available for all of them, a genuine advantage of buying British.
Who is it for?
The S400 suits three buyers particularly well. The first-time PCP owner gets a rifle with nothing to go wrong and everything to learn on. The hunter who values light weight and deliberate shooting gets arguably the purest field rifle in the range. And the shooter on a budget gets Air Arms accuracy without paying for a magazine they may not need. If you want fast follow-up shots for busy pest control, buy the S410 or S510 instead; that is the honest limit of the single-shot format.
Verdict
The S400 is proof that a great barrel, a great trigger and a consistent power plant matter more than features. It is the rifle that made Air Arms' name, and a quarter of a century later it is still one of the first rifles any experienced UK airgunner recommends. Simple, light, superbly accurate and built to outlast its owner, the classic remains a class act.
Browse Air Arms rifles for sale on Rightgun, including S400s from dealers and private sellers across the UK.
Read next:
Air Arms Ultimate Sporter review: The S510 turned up to eleven
Air Arms X200 Vanguard: The first buddy bottle Air Arms and a new direction for Hailsham
The Air Arms story: How a small Sussex factory became Britain's premier airgun maker
Air Arms S510 vs Weihrauch HW100: Britain and Germany's finest go head to head
