Maintaining The Ruger GP100

In creating the GP100, Ruger took the very popular Security Six and added advancements from the Redhawk .44 Magnum to give this .357 Magnum line a locking crane both front and rear. This idea was later used in the small frame SP101. The design of this frame allows for a wrap around grip to be used as there is no grip frame to limit the shape. A rectangular housing which is an extension of the frame holds the hammer strut and spring.

Due to this design, the normal revolver sideplate has been eliminated, resulting in a stronger frame. Along with the beefier frame, the barrel has a heavy underlug. This revolver can withstand punishment of the heaviest loads commercially available. The GP100 is chambered for the .357 Magnum, .38 Special and .327 Federal Magnum and is available in either blued finish or stainless steel with either a full or partial underlug. There are four available barrels lengths of 3, 4.2, 5 and 6 inches.

Earlier models had rubber grips with Goncalo Alves (Tigerwood) insert panels. With the popularity of the Hogue grips, the GP100 now ships standard with them instead, however, Goncalo Alves panels are again available in special edition models. "Three Modules" Disassembly Ruger states the GP100 can be disassembled into three major modules with limited use of tools, allowing the user to easily clean gun after shooting. Always open the cylinder and check to make sure the revolver is unloaded.

Safety glasses are highly recommended as you are dealing with springs under pressure. For guns with the earlier grips, remove the grip screw and screw it into the other side so there is a handle to pull off the panel. Push the round grip panel locator in, so that the other panel will pop out. There should be a disassembly pin inside the grip and might fall out when the panel is removed. Finishing pushing the grip panel locator out and the grip can now be pulled down and off.

For guns with the Hogue grips, unscrew the grip screw and pull the grip off. Unhook the stirrup from the grip panel locator and remove the locator. Cock the hammer and insert the disassembly pin into the hole that is in the mainspring strut. If there is no disassembly pin, use a paperclip instead. Keeping a thumb on the hammer spur, pull the trigger and let the hammer fall all the way forward. The mainspring assembly can now be lifted out of the frame.

Do not let the pin out of the strut because the spring is under tremendous tension and could fly off and cause injury. Pull the trigger and remove the hammer pivot. The trigger must be pulled completely to the rear to allow the pivot to come out. The hammer will now come out the of top of the frame. Ruger recommends using the mainspring housing to release the trigger guard assembly. Personally, I prefer to use a number 10 Torx screwdriver, inserted through the hole in the frame to depress the trigger guard plunger.

The trigger guard assembly will rotate down and forward. The trigger may need to be pulled while removing the trigger guard as the pawl can hang up inside the frame. While holding the revolver in your left hand, press in on the cylinder release, swing out the cylinder assembly, then remove it out the front of the frame. Detailed Disassembly Starting with the Crane, the Brownells Magna-Tip bit for the Ruger ejector (part number 080-432-

001) will make this job easier. Start with removing the front latch pivot pin by pushing down on the front latch pivot lock with a 1/16" punch. This will allow the front latch pivot pin to be pushed out to the left. The front latch, front latch spring and plunger can now be removed from the crane. The ejector rod is loose and can be pulled out the front of the cylinder. Using a non-marring hammer, tap on the crane several times to release the crane from the cylinder.

There are two steel balls that lock the crane on to the cylinder. If this is the first time the gun has been taken apart it may take quite a few taps. Looking into the cylinder, you will the center rod that sticks up through the ejector retainer. This is where the Brownells bit will make this job easy. The hole in the bit is where the center rod goes into and the screwdriver tip can engage the slot on the ejector retainer. This ejector retainer has left hand threads, so to loosen it by turning clockwise.

Once this becomes loose, the ejector retainer, ejector spring, center pin spring, center pin rod and center pin lock will come out the front of the cylinder. The ejector can now be taken off the back of the cylinder. Sometimes the front latch pivot lock and spring can be very difficult to remove. There are some that I have not been able to get out of the crane. Do not remove the steel balls in the crane as these are Supposedly, there are three modules. staked in place and should not have to be removed.

Next, the Trigger Assembly. Pull back on the trigger and remove the transfer bar. With the trigger still pulled, remove the pawl, and catch the spring and plunger that is under the pawl. Push the cylinder latch off to the right. Using a 1/16" punch, push out the trigger pivot. Pull on the trigger and lift it out of the top of the trigger guard, then remove the trigger plunger out of trigger. The cylinder latch plunger and spring can now be removed. Drift the trigger guard latch pin out. If the

gun has not been taken apart, the trigger guard latch will be in tight. You can use a pair of pliers to gently rotate it out of the rear of the trigger guard. The spring will fall out if the trigger guard is tipped down. The trigger link plunger might also be stuck. Push on it with a pipe cleaner or something similar so it can be grabbed with pliers and pulled out.

I do not recommend any further disassembly because the crane pivot lock plunger and trigger link pins are swaged at the factory and are difficult to remove. Now, the Frame. Above the bore, in the front of the barrel, is a hole that has a pin which keeps the front sight on. Pushing the pin in will release the front sight, so that it can be rotated off by lifting up on the rear of it. The front sight plunger and spring can be removed by using a pick to push them out the front.

The rear sight is held in place by across pin and elevation screw. Remove the screw first and the two springs under the rear sight can be taken out. Then the cross pin is driven out to the right. The crane latch is held in place by a screw with a slot 0.100" wide and 0.020" thick. Unscrew the crane latch pivot and push in on the crane latch from inside of the bolt face. Rotate the crane latch out to the left side of the frame.

If you look closely, there is across pin that holds the recoil plate in place on the frame. This pin is in very tight and does not like to be move. Unless there are problems with the firing pin, do not remove this. If the pin is removed, the gun will have to be reblued or at least touched up in this area. Finally, the Hammer and Mainspring Assembly. Push the hammer dog pivot pin out using a 1/16" punch. The hammer dog, hammer dog spring and plunger will be released to come out of the front of the hammer.

If the mainspring needs to be removed, put the hammer strut tightly into a vise and using two punches push down on the mainspring seat and remove the disassembly pin. This spring has a lot of pressure, so be sure to control the mainspring seat as it comes off the strut. Safety glasses area must with this spring. Reassembly for the hammer and mainspring is in reverse. The hammer dog long end is to the bottom. Reassembly Again, we’ll start with the Crane.

With the ejector pointing up on the bench, insert the center pin lock, control rod and center pin spring on to the ejector. Lower the cylinder down onto the ejector. Now take the ejector retainer and put a drop of blue thread lock on the threads. Drop the ejector spring into place and screw the ejector retainer back on, making sure to turn it counter clockwise. Put the crane back on the cylinder and insert the ejector rod to lock the balls into the cylinder.

The front latch spring and plunger are then put into position on the crane. Insert the front latch in the slot of the ejector rod and slide into the cylinder with the long slot to the bottom. Using the front latch pivot, capture the front latch. Push down on the pivot lock and finish inserting the pivot. Test the function of the ejector to make everything has been reassembled correctly. Now, Trigger Assembly. Of the two plungers, the longer plunger is for the cylinder latch.

Reassemble the trigger guard latch components into the trigger guard. Put the cylinder latch plunger and spring into the trigger guard. Insert the trigger, making sure the trigger link is seated on the trigger link plunger. Using a punch to line up the trigger to the hole for the trigger pivot pin, insert the pin from the left side. Put the pin in far enough to hold the trigger in place and place the trigger plunger into the trigger with the square cut up and to the front.

Finish inserting the pin to lock these pieces into place. Reinstall the cylinder latch by rotating it to recapture it on the plunger. While pulling the trigger, insert the transfer bar between the trigger and cylinder latch. This will hold the trigger back for the next step. Replace the pawl plunger and spring and, with a screwdriver tip, hold the plunger down. Insert the pawl into its hole and while rotating counter clockwise. Pull on the trigger to release the transfer bar and reinstall in its proper location.

Release the trigger to keep the pawl and transfer bar in place. Reassembling The "Modules" Make sure the inside of the frame and modules are cleaned, especially the tongue on the front of the trigger guard and where it mates up to inside the frame. Install the cylinder assembly back into the frame and close the cylinder. Hook the trigger guard into the frame, align the pawl and transfer bar into the proper positions and swing into place.

Using a screwdriver tip, push down on the trigger guard plunger and lock the trigger guard back into the frame. If any solid resistance is felt or it will not lock into place, recheck the positions of the transfer bar and pawl. Pull the trigger and while holding it back, reinstall the hammer. While the hammer is forward, insert the hammer pivot and then release the trigger. Insert the mainspring assembly into the frame. Position the ends of the notch to match projections of the grip frame.

The large notch goes forward, in order to allow clearance for the grip screw. While holding the mainspring assembly in position, slowly cock the hammer. You may have to jiggle the mainspring assembly to get it to rest in the recess of the hammer. Once the hammer is fully cocked, the disassembly pin should fall out or be easily removed. Pull the trigger while easing the hammer down. Install the grips in reverse order of removal. Final Safety Checks Cock the hammer and then try to release the cylinder.

It should not open. While holding the hammer, pull the trigger and release, then slowly let down the hammer. Watch the transfer bar. It should drop down and clear the firing pin. Recock the hammer. While holding the hammer again, pull the trigger and hold. Slowly drop the hammer. This time the transfer bar should not move. Open the cylinder and try to cock the hammer. The hammer should only move a half inch and stop. While resting a thumb on the cylinder, cock the hammer.

The cylinder should lock into place before the hammer locks into the cocked position. Once cocked, pull back on the hammer. There should be some play. Drop the hammer once again. With a thumb on the cylinder, slowly pull the trigger in double action. The cylinder should lock into place before the hammer falls. Failure of any of these checks will require repairs to be done before shooting the gun. AG

1 Cylinder 2 Frame 3 Trigger Guard 4 Mainspring 5 Mainspring Seat 6 Barrel 7 Pawl 8 Crane Latch 9 Grip Panels 10 Panel Inserts 11 Grip Ferrule, Right 12 Grip Ferrule, Left 13 Grip Panel Screw 14 Cylinder Latch Pivot 15 Hammer Strut 16 Hammer Pivot Assembly 17 Transfer Bar 18 Ejector 19 Hammer Dog 20 Recoil Plate 21 Firing Pin 22 Hammer Dog/Trigger Guard Latch Pivot 23 Ejector Rod 24 Ejector Retainer 25 Ejector Spring 26 Crane Latch Pivot 27 Trigger Pivot Pin 28 Cylinder Retaining Balls 29 Front Latch 30 Trigger Plunger 31 Grip Panel Locator 32 Center Pin Spring 33 Ejector Alignment Pins 34 Front Sight 35 Trigger Link Plunger 36 Trigger Guard Latch Spring 37 Trigger 38 Hammer 39 Cylinder Latch 40 Trigger Guard Latch 41 Crane and Crane Pivot Assembly 42 Firing Pin Rebound Spring 43 Recoil Plate Cross Pin 44 Cylinder Latch Spring 45 Pawl Plunger Spring 46 Cylinder Latch Plunger 47 Crane Latch Spring Plunger 48 Pawl Plunger 49 Hammer Dog Spring 50 Hammer Dog Spring Plunger 51 Crane Latch Spring 52 Crane Pin Lock 53 Center Pin Rod 54 Rear Sight Cross Pin Ruger GP100 (Speci ications subject to change without notice) 55 Front Latch Pivot Pin 56 Rear Sight Base 57 Rear Sight Elevation Screw 58 Rear Sight Elevation Springs 59 Rear Sight Windage Spring 60 Rear Sight Windage Adjustment 61 Front Latch Pin 62 Disassembly Pin 63 Trigger Link Pin 64 Crane Pivot Lock Plunger 65 Front Latch Spring Plunger 66 Trigger Link 67 Rear Sight Blade 68 Front Latch Pivot Lock 69 Crane Pivot Lock Spring 70 Front Latch Pivot Lock Spring 71 Front Sight Plunger 72 Front Sight Plunger Spring