Question 1

How do I read this chart?

Accepted Answer

Find your chronograph FPS reading in the left column, then look across to your BB weight. The number is your muzzle energy in joules. Green = under 1.14J (CQB safe at most fields), yellow = 1.14–1.49J (outdoor AEG range), red = above 1.49J (DMR/sniper territory, check your field's rules).

Question 2

Why does the same FPS give different joules for different BBs?

Accepted Answer

Kinetic energy depends on mass: KE = ½ × m × v². A heavier BB at the same speed carries proportionally more energy. That's why fields set limits in joules, or in FPS on a specified 0.20g BB.

Question 3

What FPS should my gun chrono at?

Accepted Answer

It depends on your field's joule limit and the BB you chrono with. For a 1.14J indoor limit: 350 FPS on 0.20g. For 1.49J outdoor: 400 FPS on 0.20g. Use the calculator on our homepage for any combination.

Velocity	0.20g	0.25g	0.28g	0.30g	0.32g	0.36g	0.40g	0.43g	0.48g
150 FPS	0.21	0.26	0.29	0.31	0.33	0.38	0.42	0.45	0.50
175 FPS	0.28	0.36	0.40	0.43	0.46	0.51	0.57	0.61	0.68
200 FPS	0.37	0.46	0.52	0.56	0.59	0.67	0.74	0.80	0.89
225 FPS	0.47	0.59	0.66	0.71	0.75	0.85	0.94	1.01	1.13
250 FPS	0.58	0.73	0.81	0.87	0.93	1.05	1.16	1.25	1.39
275 FPS	0.70	0.88	0.98	1.05	1.12	1.26	1.41	1.51	1.69
300 FPS	0.84	1.05	1.17	1.25	1.34	1.51	1.67	1.80	2.01
325 FPS	0.98	1.23	1.37	1.47	1.57	1.77	1.96	2.11	2.36
350 FPS	1.14	1.42	1.59	1.71	1.82	2.05	2.28	2.45	2.73
375 FPS	1.31	1.63	1.83	1.96	2.09	2.35	2.61	2.81	3.14
400 FPS	1.49	1.86	2.08	2.23	2.38	2.68	2.97	3.20	3.57
425 FPS	1.68	2.10	2.35	2.52	2.68	3.02	3.36	3.61	4.03
450 FPS	1.88	2.35	2.63	2.82	3.01	3.39	3.76	4.04	4.52
475 FPS	2.10	2.62	2.93	3.14	3.35	3.77	4.19	4.51	5.03
500 FPS	2.32	2.90	3.25	3.48	3.72	4.18	4.65	4.99	5.57
525 FPS	2.56	3.20	3.58	3.84	4.10	4.61	5.12	5.51	6.15
550 FPS	2.81	3.51	3.93	4.22	4.50	5.06	5.62	6.04	6.74
575 FPS	3.07	3.84	4.30	4.61	4.91	5.53	6.14	6.60	7.37
600 FPS	3.34	4.18	4.68	5.02	5.35	6.02	6.69	7.19	8.03

Airsoft FPS to Joules Chart — All BB Weights

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