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Pellet Guide · Air Arms S510

Best Pellets for the Air Arms S510: A Tested Approach

The best pellet for the Air Arms S510 is the one your S510 shoots tightest — and with a match-grade barrel, the difference between candidates is measurable. This guide covers where owners commonly start in .177 and .22, and how to run the test that settles it properly.

Why the S510 rewards a proper pellet test

The S510 is a pre-charged pneumatic sporter built around a shrouded Lothar Walther barrel, offered in .177, .22 and .25, in both regulated and unregulated forms. Air Arms lists a 395 mm barrel, and regulated versions fill to 250 bar against 190 bar for unregulated ones. All of that matters for one reason: a barrel this consistent will show you real differences between pellets rather than burying them in noise.

Three things about the S510 shape a sensible test:

• Match-grade barrel. A good barrel is more pellet-sensitive, not less. Head-size differences of 0.01 mm that vanish in a budget barrel can show up clearly here.
• Regulated or not. On an unregulated rifle, velocity drifts across the fill. Test inside the flat part of the curve or you're measuring air pressure, not pellets.
• Sub-12 or FAC. A UK sub-12 ft·lb S510 and an FAC-rated one will not agree on pellet weight. Heavy pellets that stabilise beautifully at higher power can drop out of their comfortable window at 11.5 ft·lb.

Where S510 owners commonly start

These are the pellets that come up repeatedly in UK airgun forum threads and published reviews for the S510 and its Air Arms stablemates. Treat this as a shortlist to test, not a result — we have not run controlled tests on your rifle, and neither has anyone else.

.177

Pellet	Typical weight	Why it's on the list
Air Arms Diabolo Field	8.44 gr	The house pellet; made by JSB and the most commonly reported starting point for Air Arms rifles.
JSB Exact	8.44 gr	Long-standing field target reputation; near-twin to the Air Arms equivalent.
JSB Exact Heavy / AA Field Heavy	10.34 gr	Frequently reported as the better performer at longer range and in wind — worth testing even sub-12.

.22

Pellet	Typical weight	Why it's on the list
Air Arms Diabolo Field	16 gr	The default recommendation for .22 Air Arms rifles; medium-heavy suits the platform.
JSB Exact Jumbo	15.89 gr	The direct JSB counterpart; commonly tested alongside the Air Arms tin.
JSB Exact Jumbo Heavy	18.13 gr	Owners regularly report heavies grouping best at 50 yards, particularly on FAC rifles.
Other reported options	varies	QYS Streamline Heavy, Norma Golden Trophy and JSB Hades (hunting) all appear in owner threads.

Whichever you pick, buy them in two head sizes where the retailer offers a choice — commonly 4.51 and 4.52 mm in .177, and 5.51/5.52 mm in .22. Re-testing one pellet across two head sizes is routinely the cheapest accuracy gain available, and it's the variable most owners never touch.

How to run the test

The method is the same one in our pellet testing guide — the short version, adapted to the S510:

1. Three to five candidates from the shortlist above, ideally spanning two weights and two head sizes.
2. Off a rest, bipod or bags. You're testing the pellet, not your hold.
3. One distance, the one you actually shoot — 25 or 50 yards for most field use.
4. Inside the good part of the fill. On an unregulated S510, skip the first and last handful of shots. On a regulated one, stay above the reg's working pressure.
5. Two or three 5-shot groups per pellet, all in one session, in similar wind. A single group lies.
6. Measure every group and compare averages. Not "that looks tighter" — the actual millimetres.

Wind is the variable most likely to corrupt the result, and lighter .177 pellets are the most exposed to it. If it's gusty, either wait or read reading the wind for air rifle first and test on the lulls. Use the group size chart to check what your numbers mean at your distance.

What to log (and why the lot number matters)

A pellet test is only worth as much as the record you keep of it. For every group, log:

• Pellet, weight and head size — "JSB Exact" alone won't be enough in six months.
• Lot / batch number from the base of the tin. Batches shift. If you find a great tin, buy more of that lot; if your groups suddenly open up, a batch change is the first suspect.
• Distance and group size in millimetres, centre to centre.
• Conditions — wind, temperature, and for the S510 specifically, where you were in the fill.
• Velocity if you have a chronograph. Extreme spread and standard deviation tell you whether the rifle or the pellet is the limiting factor — see chronograph numbers explained.

Frequently asked

What is the best pellet for an Air Arms S510?

There's no single answer that holds for every rifle. Owners most commonly report good results with Air Arms Diabolo Field and JSB Exact domed pellets in the heavier weights for the calibre — but individual barrels differ, which is the whole reason to test. Shoot three or four candidates over measured groups in one session and let the numbers decide.

Should I shoot .177 or .22 in an S510?

The S510 is offered in .177, .22 and .25. In a sub-12 ft·lb rifle, .177 gives a flatter trajectory and more forgiving range estimation; .22 delivers more retained energy per shot and remains popular for hunting. Neither is inherently more accurate — pellet-to-barrel matching matters more than the calibre you pick.

Do Air Arms and JSB pellets actually differ?

Air Arms Diabolo Field pellets are made by JSB in the Czech Republic, and shooters widely regard them as very close to the equivalent JSB Exact products. Reported differences are subtle and vary by production run. Include both in a test rather than assuming.

Does head size matter on the S510?

Yes — arguably more than on a cheaper rifle, because a match-grade barrel will show the difference. Premium pellets are sold in head sizes such as 4.50, 4.51 and 4.52 mm, and a 0.01 mm change can visibly tighten or open a group. Testing one pellet in two head sizes is the cheapest accuracy experiment you can run.