Remington Model 4, 742, 7400 disassembly notes

Big game hunters in the United States traditionally had two options in semi-automatic rifles, the Browning BAR and Remington 7400. While I’m not particularly fond of either, they both offer shooters quick follow up shots and reduced recoil over traditional bolt action designs. In this post we’ll take a quick look at the 7400 and how it is disassembled for maintenance.

We have a lot of older Remington semiautomatic rifles walk into the shop in need of repair. Unlike modern semi-automatic rifle designs, the Model 4, 742, and 7400 rifles are extremely difficult to take apart. Basic maintenance, including detailed cleaning or recoil spring replacement, requires disassembly.

For reference purposes, a schematic of the 7400 can be found here.

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In this post, let’s take a look at some tips on how I disassemble these rifles. After the rifle is safe and empty, I remove the screw located on the front of the forearm.

With the screw removed, the front end can slide off.

Removal of the fore end exposes the gas block. The gas block retains the action parts with a roll pin which needs to be drifted out with a roll pin punch.

Once the roll pin is removed, the recoil system and spring can be removed.

Since the gas port is hard to access, most rifles we take apart need this area cleaned.

Next the barrel nut needs to be removed. This is located in front of the receiver and is simply unscrewed with an open end wrench.

To remove the bolt assembly, the charging handle needs to be removed. This can be fairly difficult. A pin retains the handle. You can see it in the center of the picture above. This pin passes through the bolt carrier at an angle.

From the top of the rifle you can see the other side of the charging handle’s retaining pin.

To remove the pin I drift it from the top down with a pin punch.

Once the pin is drifted free, the charging handle can be removed and the rifle can be taken apart further. To disassemble the bolt and carrier, the firing pin’s retaining pin needs to be drifted out. I only complete this task if necessary.

Often on these rifles the plastic ejection port cover needs to be replaced. In this image you can see the old one (above, right), next to the new part (above, left). Since the part is fairly inexpensive, I’ll routinely change it out once the gun is apart.

Prior to reassembly, I make sure to clean it well. If you don’t work on these rifles regularly, it might be a better idea to have you local gunsmith handle repairs. When he tells you that they are difficult to work on, believe him, they are!