Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Durkin Tactical Franklin Armory
User Panel

Do I want SS-109 or M855 then?


Between the two? Probably M855. As noted you never know for sure what your going to get with loads that are only marked SS-109. M855 shouldn't cause you any problems and is generally well liked by AR15 shooters. Don't worry if ammo is labeled as SS-109/M855. That should be M855 spec.

Note: M855 is effectively a implementation of the SS-109 interoperability standard (so all NATO members can shoot each other's ammo). The US, however, requires stricter standards in M855 and as a result, M855 manufacturers generally load their rounds to hit at least 3000 fps at 78 feet from the muzzle. The SS-109 specification had a lower 2985 fps requirement and British SS-109 rounds are slower still (2700-2800) to deal with the SA80 rifles.

Opinion: Some British SS-109 reportedly is underloaded (in order to permit proper operation in the L-85 Bullpup also called the SA-80 rifle) and therefore causes some short cycling in Bushmasters and Colts and isn't likely a good choice for emergency or critical use ammo.

Close Join Our Mail List to Stay Up To Date! Win a FREE Membership!

Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!

You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.

By signing up you agree to our User Agreement. *Must have a registered ARFCOM account to win.
Top Top