MG 45

The MG 45 (also known as the MG42V) was a machine gun based on the MG 42, which was developed but not fielded in significant numbers by the German Army in World War II.

Overview

The MG 45 differed from the MG 42 in that it did not completely lock its breech before firing, increasing its rate of fire and simplifying its construction. In 1944, the material shortages of the Third Reich led to the development of a newer version of the MG 42, the MG 45 (or MG 42V). This had a different operation mechanism that used delayed blowback as opposed to roller locking.

Roller-delayed blowback-operated breech for automatic weapons

The MG 45/42V was a Roller-delayed blowback-operated firearm with a semi-rigid locking mechanism designed to retard the rearward movement of the bolt. This delay was achieved by artificially increasing the inertia of the bolt by using an angular, interposed transmission system, installed symmetrically to the bore axis, with two cylindrical rollers acting as transmission elements against a movable locking piece which drives the heavy bolt carrier. The two-piece bolt assembly consists of a bolt head, which contains the aforementioned rollers, and a supporting locking piece and bolt carrier. During the "unlocking" sequence, the bolt head receives the recoil impulse from the ignited cartridge and exerts rearward pressure against the rollers, seated in recesses in the barrel extension. The rollers are driven inward against angled ramps of the barrel extension and interact with the wedge-shaped locking piece, projecting it backwards. Thus a transmission ratio is maintained (as long as the rollers move on the inclined surfaces of the barrel extension and locking piece) of the bolt carrier and locking piece relative to the bolt head; the bolt carrier travels backwards considerably faster than the bolt head, ensuring a safe drop of pressure within the barrel prior to extraction. Extraction is carried-out under relatively high pressure. It is unknown whether the MG 45/42V had longitudinal gas relief flutes in the chamber designed to help free the bloated cartridge casing from the chamber walls during extraction. Fluting the end of the chamber provides pressure equalization between the front outer surface of the cartridge case and its interior and thus ensures extraction without tearing the tapering part of the case of bottle necked cartridges. Werner Gruner stated that gas relief flutes were present, his colleague Hans-Joachim Kaltmann denied this.

The MG 45/42V is considered a different type of firearm than the MG 42, as the operating mechanisms of these two machine guns are different. Compared to the MG 42 the MG 45 used steel of lesser quality, the weight was reduced to 9 kg (19.8 lb), while retaining the horizontal cocking handle. The MG 45 bolt weighed 845 g (29.81 oz). First tests were undertaken in June 1944, but development dragged on and eventually only ten were built. During tests a MG 45/42V fired 120,000 rounds in succession at a cyclic rate of fire around 1,350 rounds per minute.

The MG 45/MG 42V had some influence in the post-war development of the roller-delayed blowback system, as employed the SIG 510 assault rifle, SIG MG 710-3, Heckler & Koch HK 21 general purpose machine guns and other in modern CETME and Heckler & Koch small arms.

See also

• Barnitzke machine gun
• MG 60—post World War II derivative

References