Features and Characteristics
Inside Surface Treatment
Chromium, qq-c-320, class 2a
Overall Length
1143.0 millimeters
End Application
RECO-IL-AMP-LIFI
Size Designation
.50 caliber
Special Features
Phosphate is not sand blasted or applied to internal surfacesl supplemental oil treatment is applied after painting; paint is heat resistant per mil-std-193, color no. 15200 of fed-std-595, applied to specific external surfaces only; chromium plating is applied only to internal surfaces; no mechanical method for removal of chromium platepermitted; plating will produce a continuaaly diminishing dia. Towards the muzzle, except that from the origin of rifling to within 102 mm. Of the muzzlend; a variation of 0.025 from a continually diminishing dia. Is permissible and 0.013 variation is permissible over the remaining lg. Provided that resultant surfaces remain within densional limits for bore and groove dia.; heat treatment is to heat barrel and piston at 1550-1575 deg. F., oil quench, temper 1 hr. Min. To rockwell hardness rc 28-36; gas ports-holes are located within barrel rifling grooves
Material
Steel, aisi 4150 and steel, aisi 4140
Material
Steel comp 4150 and steel comp 4140
Material Specification
Aisi 4150 assn standard 1st material response and aisi 4140 assn standard 2nd material response
Surface Treatment
Phosphate manganese and paint
Surface Treatment
Phosphate, mil-p-16232, type m, class 1 and painted
Type/model Designation
M3
FSC
1005 Through 30mm Guns
NSN: 1005-01-328-5882
