How to Reassemble Remington R51
Remington R51 Reassembly Tips
Here are a few reassembly tips for the Remington R51:
Take your time with this gun and don’t get frustrated. This is a difficult gun to put back together.
Several of the pins on this gun have knurling. Be sure to align the knurling notches/marks before setting those pins. It will increase the life of your frame.
Most of the pins on this gun are set right to left
Before getting started on this reassembly, make sure you have the following tools:
Screwdriver Set
Punch Set with Starter Punch
Nylon/Brass Hammer
Bench Blocks/Hockey Pucks with Drilled Hole
Pick and Hook Set
Needle Nose Pliers
* Disclaimer: I don’t know the name of every part on this gun so if you need a reference please use this parts diagram: https://www.gunpartscorp.com/gun-manufacturer/remington/auto-pistols-rem/r51
Step 1: Trigger Reassembly
Start by putting the trigger bar onto the trigger shoe with the hooks facing upward toward the top of the pistol. Line up the pin holes.
Set the tiny roll pin. You might need to get it started without the trigger bar. This is a roll pin into a plastic part so use the nylon side of the hammer—it don’t need much force.
Set the trigger spring onto the trigger. The disconnected side should be set closer to the trigger bar. Rotate the trigger bar into the horizontal position.
From the back of the gun, feed it into the trigger housing. Line up the hole in the trigger and the hole in the frame.
Put the trigger pin into place—right to left—with your fingers. Once it’s into the frame up to the knurling, rotate the pin until you can find the notches in the frame that the pin came out of. This will increase the life of your frame. If the pin is continuously put in the frame in a different orientation (without lining up the notches), it will make the hole bigger.
Set the trigger pin in with a larger diameter punch. Once the pin is close to being set all the way, switch to a starter punch. Set the pin until it is flush with the frame.
Step 2: Magazine Catch Reassembly
Don’t put the magazine catch in before the mechanism. Put the magazine catch spring into the magazine catch with the short, perpendicular leg in the notch and the long, parallel leg hanging off the side—this part of the spring will sit on the ledge in the frame.
Start the pin before trying to set the mechanism into place. The tab on the magazine catch needs to be behind the swell in the frame behind the trigger. Make sure the trigger bar is up so you can get the spring leg under it and onto the ledge in the frame.
With a needle nose pliers, grab the mechanism and turn it to the side so that the long, parallel leg of the spring can go under the trigger and over the notch in the frame. When it’s in place, push the pin through with your finger.
Before setting the pin, be sure that the magazine catch mechanism is in operating position and can move back and forth. Now, push it all the way down and out of the way by prying it up with one finger and then using a punch through the bottom of the magazine well to hold it out of the way. Slide the magazine catch into place and let the mechanism go. This should allow the magazine catch to work. Now you can set the pin.
Step 3: Ejector & Disconnector
Set the ejector in. The ejector has a hole in the end of it which needs to line up with the tiny half pin in the back of the gun. Set it into the notch next to the pin and then slide the ejector onto the small half pin.
Then take the disconnector and put it in by rotating it up and into place. Put the hammer pin back into its hole up to the knurling temporarily—this will hold those parts in place for now.
Step 4: Sear and Hammer Reassembly
To put the sear and hammer block back in, slide the sear pin in slightly—just through the hole in the frame and through the disconnector.
Set the red sear spring in place on the sear pin. Then set the sear onto the pin with the boss of the sear facing the outside of the gun.
Set the hammer block spring onto the boss of the hammer block. Together, slide those onto the sear pin with the boss of the hammer block facing the outside of the gun.
Be sure the springs are oriented correctly with the long part of the springs resting on the shelf in the frame and the small hook on the other end sitting on the backside of the sear and hammer block—the two hooks should be facing each other. Be sure the sear and hammer block are also in the correct orientation—they should be on the outside/backside of the trigger bar.
Push the pin all the way through to hold it in place. Set the sear pin right to left. Now you can take the hammer pin out.
Next is the grip safety spring. The long leg will be toward the back of the gun facing down, and the short leg will be toward the front with the leg facing the outside of the gun. You will have to rotate it about 90 degrees to get it into place in the frame.
Put the hammer back in by sliding it up through the bottom of the gun. In order to get it into place, you’ll have to move the sear out of the way by pushing slightly forward on the hammer strut.
Set the hammer pin by punching it right to left.
Step 5: Grip Safety & Main Spring Reassembly
Next is the grip safety mechanism. Put the tiny spring into the hole of the grip safety mechanism.
Hold the part in place inside the frame with the tiny spring facing down and the side with the channel facing the back of the gun. Line up the holes for the pin. On the left grip, there are two holes. Put a pick through the bottom hole and push the tiny spring out of the way. This will help you get the pin through. Push the pin through right to left. Slowly move the pick out of the way as you slide the pin into place. These are friction fit pins so they don’t need to be set with a hammer. They should push into place.
Put the grip back on the right side and screw the grip down—don’t forget the rubber washers! This will hold the pin in while you reassemble the rest of the gun.
Now, on the left grip, push the top pin into place. Keep your thumb on these two pins on the left grip for the rest of the assembly. This will keep them from falling out.
Pull the trigger to let the hammer fall. The hammer should be forward to complete the final frame reassembly tasks.
Now put the grip safety backstrap back on. The grip safety spring needs to ride on the ledge of the backstrap and the hammer strut needs to go into the hole in backstrap. Slide the grip safety backstrap into place—make sure to push it straight in.
Now, put the main spring, main spring plunger, and the main spring cap back together into one unit. Push the entire unit into the main spring housing hole with the plunger first and the cap on the outside of the gun. While pushing those into place, push the main spring pin in from right to left.
Put the grip back on quickly so none of the pins fall out. Be sure to screw on the grips with the rubber washers!
Cock the hammer.
Put the slide stop return spring back into the frame. Push the protruding leg down into the hole of the frame and then rotate the spring into place with half of it inside the frame.
Step 6: Breech Block Reassembly
Slide the firing pin spring onto the firing pin. Then slide the firing pin into the breech block with the slot toward the top of the breech block.
From right to left, slide the pin which holds in the firing pin into the breech block. It should go almost all the way in without a punch. To set the pin, use an oversized punch.
Put the rubber buffer (which functions as a spring) into the extractor. Set the extractor onto the breech block. Line up the holes and set the pin from the bottom to the top.
Step 7: Slide Reassembly
Put the spring in the bushing and guide it into the slide with the bushing facing the back. Compress the spring until the bushing catches on the notch—this will hold it in place angled upward. Slide the barrel into the bushing. Pull the bushing forward and release the spring.
Line up the barrel with the hole in the front of the slide. Compress the spring and bushing to pull the barrel forward through the hole in the slide. This will allow you to fit the breech block into place. Keep your fingers on the knurling of the barrel.
Slide the breech block into place. Continue to hold the knurling of the barrel.
Guide the slide onto the frame of the gun. When it’s all the way on, release the barrel.
Finally, pull the slide backward until the notch in the frame matches the one in the slide. Hold it in place and put in the slide stop in. Release the slide and frame.
That’s a reassembled Remington R51. We hope you found this explanation useful. If you have any questions, comment below. Thank you for reading!
