M3 Magazine Spring

M3 Grease Gun Mag Spring

This United Defense spring is a replacement for the magazine of the M3 submachine gun, the .45 ACP weapon better known as the Grease Gun. A magazine spring pushes the follower and the stacked cartridges up toward the feed lips, so a tired or kinked spring is one of the most common causes of failures to feed. Collectors, shooters and restorers who keep an M3 running use a fresh spring to bring an old magazine back into working order.

Features

• Made For The M3 Magazine — Sized as a replacement part for the M3 Grease Gun box magazine rather than a generic spring cut to length.
• Helical Coil Design — A long, evenly wound wire coil compresses as rounds are loaded and stores the energy that lifts each cartridge into position.
• Restores Feed Tension — Swapping out a weak original spring helps return consistent upward pressure on the follower through the whole magazine.
• Black Finish — The wire carries a black finish, matching the dark look of the magazine body it sits inside.
• Formed End Coils — Shaped coils at each end seat the spring against the follower at the top and the floorplate at the bottom.
• Single Replacement Spring — Each order is for one magazine spring, so you can rebuild exactly as many magazines as you need.
• United Defense Brand — Supplied under the United Defense name as a dedicated part for this platform.

Fit and Installation

The spring fits inside the M3 magazine body between the follower and the floorplate. To install it, remove the floorplate, draw out the old spring, then insert the new one with the follower seated on top before closing the magazine back up. If an M3 magazine feeds sluggishly or the follower sits low when empty, the spring is the first part to check.