Un-sponsored Review of Air Arms S510 Xtra Superlight FAC .22 PCP Air Rifle

Velocities at different power levels w/ JSB 18.1
Power 1, 523 fps = 11 FPE
Power 1.5, 580 fps = 13.5 FPE
Power 2, 705 fps = 20 FPE
Power 2.5, 762 fps = 23 FPE
Power 3, 814 fps = 27 FPE
Power 4, 880 fps = 31 FPE
Power 5, 897 fps = 32 FPE

Scope: Athlon Argos, first focal plane reticle. (so it zooms with the magnification and the hash marks are always the same amount of drop) Excellent scope, but big and heavy. About $400 at this time.

Medium cheapo UTG rings are a perfect height with a 50mm objective scope.

More data. Shot string summary, filled to 195 bar (2900 psi), JSB 18.1, Power 4/5
Shot # / BAR / FPS
10 / 180 / 864
20 / 165 / 888
30 / 155 / 877
40 / 140 / 860
50 / 120 / 813

Stats for first four mags (40 shots) only:
Avg. velocity: 870 fps
ES: 57
SD: 14
Avg. Energy: 30.2 FPE

Stats for 5 mags. (50 shots)
Avg. Velocity: 863 fps
ES: 76 fps
SD: 21
Avg. energy: 29.8 FPE

Similar models from Air Arms:

S400: single shot, bolt action
S410: repeater, bolt action
S500: single shot, side lever
S510: repeater, side lever
S410 TDR: Take-down version of the S410. US model includes a fake moderator

JSB 18.1 is the most accurate pellet, about tied with the JSB 15.89. It also shoots Polymag Shorts pretty well at Power 2/5. I only tested them out to 20 yards. Group sizes are notably larger than the JSB domes, but still good enough for lung shots on squirrels at that distance. Air Arms Heavies and 16 gr. aren't quite as good as their equivalent JSBs. Baracuda Match are good, but are notably tougher to chamber. Baracuda Hunter are not very accurate, to my dismay.

Pumping up the gun with my Hill Mk. III pump is not a big deal. I do it in two sessions, and I'm not in great shape. Bigger air tube or tank = harder to pump. Higher fill pressure (230 bar is not uncommon now) = harder to pump. Regulated = harder to pump. (since it uses more of the air in the tank)

It is now wearing a Hawke Vantage 4-12x50 IR scope, to lighten it up a bit.

Feel free to ask questions.