Inner Barrel Prometheus EG 6.03 SOPMOD/M4A1/SR16/SG551 363 mm

For those who want to replace the original inner barrel of the SOPMOD, M4A1, SR16 or SG551, the Prometheus EG inner barrel is a solid choice. Accuracy improves noticeably — partly due to the improved air seal, and partly because the hop-up can do its job better with a quality inner barrel. Be sure to use high-quality BBs to get the most out of the barrel.

Stainless steel is the material Prometheus chooses, and it has a number of practical advantages. The barrel is difficult to deform and holds up well with rougher use. Moreover, stainless steel has a lower coefficient of thermal expansion than brass or aluminum — the materials most inner barrels are made from. When the barrel heats up because many BBs are fired, the impact on accuracy is therefore limited.

The dimensions are tight: an inner diameter of 6.03 mm with a tolerance of only +/- 0.01 mm, and an outer diameter of 8.5 mm. The finish is accordingly. At the end of the barrel, the inner diameter tapers slightly, so that the pressure decreases gradually rather than abruptly — which prevents instability at the muzzle. A common upgrade for sport shooters who want more consistency from their replica.