Went to the range today with tcr (thanks) and shot 5 different surplus ammos including one tar sealed. Out of 80ish rounds out of 2 mags we had not problems what so ever. The aw84xx was great and was very accurate. The bolt gap has held from the initial .03 drop round count is still low (140) but so far so good. The barrel has 11 flutes. It is an F model with an 18in barrel. So far could not be happier....may go to the range tomorrow as I had a blast!