XM177: 5.5" moderator straight wall or conical?

[Todd.K]

1) By a wide margin. Find an over the barrel version you can get pinned to a 14.5” barrel.

This number 1

[Stopsign32v]

This number 1

Again cloning it. I don't care much about flash or noise it will be a range toy. I am nervous about horrible accuracy though with a 5.5" FH

[Ned Christiansen]

With that #1 option it will look the same but give you another 150-200 FPS which some day you may be glad you had, plus your accuracy concerns are gone. There is a guy that specializes in the clone thang, bet he has the preferred combo whichever you choose, but I can't think of his company name just now. Charlie's Clones maybe?