The BR
The primary weapon of most characters in both The Blood Gulch Chronicles and Recollections.
Including: Simmons, Grif, Tucker, Washington, C.T., all Command units, all Freelancers except Meta and Wyoming, Sarge when losing his Shotgun, C.T.'s units etc.
The marksman rifle is the substitute for the BR in Halo Reach.
Simmons and Grif holding marksman rifles instead of battle rifles for Halo Reach.