I am not an attorney nor an engineer, but a quick read of the United States Munitions list would give me great concern before I started shipping parts overseas. See definition F. below.
Category Iâ€"Firearms, Close Assault Weapons and Combat Shotguns
*(a) Nonautomatic and semi-automatic firearms to caliber .50 inclusive (12.7 mm).
*(b) Fully automatic firearms to .50 caliber inclusive (12.7 mm).
*(c) Firearms or other weapons (e.g. insurgency-counterinsurgency, close assault weapons systems) having a special military application regardless of caliber.
*(d) Combat shotguns. This includes any shotgun with a barrel length less than 18 inches.
*(e) Silencers, mufflers, sound and flash suppressors for the articles in (a) through (d) of this category and their specifically designed, modified or adapted components and parts.
(f) Riflescopes manufactured to military specifications (See category XII(c) for controls on night sighting devices.)
*(g) Barrels, cylinders, receivers (frames) or complete breech mechanisms for the articles in paragraphs (a) through (d) of this category.
(h) Components, parts, accessories and attachments for the articles in paragraphs (a) through (g) of this category.
(i) Technical data (as defined in §120.10 of this subchapter) and defense services (as defined in §120.9 of this subchapter) directly related to the defense articles enumerated in paragraphs (a) through (h) of this category. Technical data directly related to the manufacture or production of any defense articles enumerated elsewhere in this category that are designated as Significant Military Equipment (SME) shall itself be designated SME.