Gas
because they where good.
Firebases acted as Forts during the Vietnam War. Firebases normally had a battery (6 guns back then) of 105mm, 155mm Self Propelled Guns (SPG), or split trailed 155mm field guns. Some firebases had M42 Dusters and 175mm SPG.
There were 3 Duster battalions in South Vietnam: 1/44th in I Corps, 5/2nd in II Corps, and 4/60th in III Corps. Dong Ha was in I Corps.
138 miles taking this route:Take A453, from Nottingham, to A42 (to M42) to BIRMINGHAM.Take A42 & M42 to M5 (S) to The SOUTH WEST.Take M5 down to Bristol.
130 miles taking this route:Take A512 ASHBY, from Loughborough, to A42 (to M42); once you are at A42, follow signs to A42 (to M42) to The SOUTH WEST to BIRMINGHAM.Take A42 & M42 to M5(S) to The SOUTH WEST.Take M5 down to BRISTOL.
33 miles following this route:Follow signs out of the airport, then follow signs to A42 & M42.Follow A42 & M42 to Birmingham.
You can get the 666a to the M42 nebula, but you'll have to walk from there.
105 miles taking this route:Take M1 (S) LONDON, from Wakefield, to A42 (to M42) to The SOUTH WEST to BIRMINGHAM at JUNCTION 23A.Take A42 & M42 to Birmingham.
By Car, up the M42/A42.
M42, m5 about an hour - twenty
120 miles taking this route:Take M5 to The NORTH (towards BIRMINGHAM), from Worcester, to M42 LONDON (via M40) at J4A.Take M42 to M40 LONDON at J3A.Take M40 into London.
M42, the great Orion Nebula, is a region of very young stars within a giant molecular cloud whose total mass is estimated to be approximately 500,000 times that of the Sun About 1600 light-years from Earth, M42 lies on the edge of its parent giant molecular cloud, which in turn is but one of a vast systems of such clouds found in this part of the Galaxy.