Anyone have any advice on disassembly of a Ruger M77 mkII firing pin assembly? I plan to install a heavier striker spring, but I've never disassembled a ruger m77 firing pin assembly. Any quick suggestions? Thanks, ZT
Owner's manual. They'll send you one if you don't have.
(Rifle Must Be Unloaded Prior To Disassembly)
1. Keep the rifle pointed in a safe direction! Put the safety in the “Load-Unload”
2. CHECK TO BE CERTAIN THAT THE CHAMBER AND MAGAZINE ARE EMPTY.
3. To remove the bolt: Open bolt and pull to the rear while at the same time
pivoting open the bolt stop which is located on the left side of the receiver on
the right-handed version and the right side of the receiver on the left-handed
version. This is as far as you need to dismantle the rifle for a routine cleaning.
It is rarely necessary to proceed further.
4. To remove firing pin assembly from bolt: With bolt out of the rifle and firing
pin cocked, insert a pin or nail into the “disassembly hole” in the cocking
NOTE: The pin or nail should be as close as possible in size to the hole
diameter, and at least 2 inches long so that it can be used to ‘lever’ the firing
pin to the rear when reassembling the firing pin assembly into the bolt.
Unscrew firing pin assembly and remove from bolt. (Caution: Do not remove
the restraining pin until firing pin assembly is reassembled into bolt).
CAUTION: The firing pin assembly is intended to be a permanent
assembly and should not be disassembled. The parts are under great
spring pressure and if disassembled could fly apart with sufficient force to
cause serious injury. Also, special tools are required to correctly
reassemble this part.
5. To remove stock: Open floorplate and while holding it up out of the way,
loosen and remove the screw that holds the floorplate hinge assembly. Next,
loosen and remove the screw that is just forward of the trigger guard. Remove
trigger guard. Remove magazine box. (If magazine box does not come out
readily, do not force it. It can be lifted out with the barrel-receiver assembly,
but it must be done with great care.) Lift barrel from the stock very carefully.
Lift the receiver at the same time as the barrel is lifted so that the barrelreceiver
comes out of the stock level and not at an angle.
6. To remove the trigger: (Safety Selector should be in the “Fire” position.)
While holding the trigger in place, press out the trigger pivot pin.
(Caution: Trigger is spring loaded.)
7. To remove the sear:
a. Press out the sear pivot pin.
b. Turn receiver upside down and slide sear forward. Sear will drop out of the
top slot in the receiver.
8. To remove safety assembly:
a. Rotate the safety selector so that the upper section is positioned fully over
the center of the receiver tang.
b. While holding the safety selector in place with thumb and forefinger, slide
the retainer up out of receiver. (Caution: Safety Selector is under spring
tension from a spring and plunger acting against the lower section of the
safety selector. The spring and plunger will jump out if not contained.)
c. Lift out the safety selector.
d. Remove the safety selector detent and safety selector detent spring.
(Again, Be Sure Rifle Is Unloaded)
1. To replace the safety assembly:
a. Place the safety selector detent and safety selector detent spring into the
hole in the receiver.
b. Set the safety selector in place with its upper section positioned over the
center of the receiver tang.
c. While holding the safety selector in place with thumb and forefinger while
applying downward pressure, slide the safety selector retainer into dovetail
from the top. Align the notch in the safety selector retainer with the sear pivot
2. To replace the sear:
a. Place the rear end (the end with the hole in it) of the sear into the slot from
the top of the receiver. Swing the rear end of the sear up and slide the sear
into position until the hole in the sear is aligned with the mating holes in the
b. Insert the sear pivot pin.
3. To replace the trigger:
a. Place the trigger/sear spring over the dimple in the trigger.
b. Assemble the trigger while aligning the spring with the dimple on the sear.
c. While holding the trigger in position, replace the trigger pivot pin.
4. To replace the stock:
a. Install magazine box on receiver.
b. Place barrel-action assembly – with magazine box in place – into stock.
c. Replace trigger guard and loosely install screws.
d. Install floorplate hinge assembly and firmly tighten screw. (This screw is
angled and draws the barrel-action assembly into the bedding surface of the
e. Tighten the two trigger guard screws as follows: Do not tighten one screw
all the way and then tighten the other. Instead, alternately tighten each one –
a partial turn at a time – so that the screws will be tightened equally until both
are snugly tightened.
5. To reassemble firing pin assembly into bolt:
Screw the assembly fully into the bolt. The assembly is properly positioned in
the bolt when the flat on the bottom right side of the bolt sleeve (front of bolt
facing you) is aligned with the flat on the bottom end of the bolt handle. Note:
There is a shallow notch on the rear end of the bolt body – at the end of the
cam cut – into which the nose of the cocking piece ‘fits.’ When the firing pin
assembly is being turned into the bolt body, it may be necessary to use the
restraining pin as a lever to slightly retract the cocking piece nose so it can be
moved into the notch. When the firing pin assembly is correctly positioned in
the bolt body, the restraining pin can be removed, but not before!
6. To replace bolt:
a. With bolt handle in an upward position and bolt head away from you, align
the extractor with the right hand locking lug in the right-handed version or
the left locking lug in the left-handed version. Align the locking lugs with the
channels in each side of the rear of the receiver and partially insert the bolt.
b. Push the bolt fully forward.
REGARDING ACCURACY: The accuracy of any rifle can vary depending upon the
make and type of cartridges used in it. Such being the case, if your RUGER®
M77® MARK II rifle does not perform to expectations, it is advisable to try
several brands and types of cartridges to determine which one delivers the best
accuracy, before proceeding further. If your rifle is not as “accurate” as you
believe it should be, before concluding that some serious fault exists, run the
1. Be certain the two trigger guard screws and the floorplate hinge screw are
snugly tightened as described in Step 4, p. 20, of the “Reassembly” section of
2. Be certain the bore is clean and free from accumulated metal fouling
(deposited by metal jacketed and lead bullets). See the “Care and Cleaning”
section of this manual.
3. Check the sights for tightness, setting and alignment.
If everything is tight, the bore is clean, the sights are properly aligned and secure
but the accuracy problem persists, DO NOT alter the stock bedding in any way.
Do not scrape away wood and do not bed with “glass,” plastic, epoxy, etc. Once a
rifle stock has been altered, it cannot be reworked by our Product Service
If you still have an accuracy problem, write a brief letter to our Product Service
Department in Newport, New Hampshire 03773 and describe the nature of the
problem based on the use of factory-loaded cartridges – not reloads. You will
receive a prompt response from us and if indicated, detailed instructions with
regard to the return of the rifle.
You can download the manual in PDF format from Ruger HERE
Thanks for posting the manual, but I got that far. I'm trying to take apart the firing pin assembly to replace stiker spring. Ruger's manual states that is not to be deassembled, but I'm trying to install a Wolff spring. I think I need to knoch out the pin that attaches firing pin to the striker block. I was hoping someone could share some secrets.
ANyone know how to take apart the firing pin assembly. Do you know out the pin found underneath block??