KS Arms & MPA 25 Creedmoor.

[u/MoosedMilk]

Absolute Rock Solid PRS rig ready for the next match!

[u/alexorange178]

I also have SA3R action but I wish I knew it was almost impossible for the user to change firing pin and spring without sending it back to KS before buying it.

[u/MoosedMilk → u/alexorange178]

I wouldnt really call undoing one allen screw "almost impossible" but YMMV. Definitely not as easy as a Factory R700 or a Model 70.

[u/alexorange178 → u/MoosedMilk]

Here are the instructions from KS, You will need a small heating torch, a brand new 1/16" allen key, a bench vice, and a 3/8" wrench, one of our bolt tools helps to have as well
-Record the protrusion to 3 decimal places(ex; .056") if possible. Firing assemblies are individually set anywhere between .05-.06" for best/free functioning.
-Remove firing pin assembly from the bolt body, then carefully clamp it in a vice, best to hold on the cylindric portion of shroud, so that you have access to the 3/8" wrench flats at the front of the firing pin and so that you are free to heat the back of the assembly where the cocking piece is so the heat does not run away" into the vice too much.
-Apply a conservative amount of heat directly onto the cocking piece then try with the allen key to open set-screw, if it does not move do not try to force it but rather apply more heat and try again. Please try to avoid heating the main spring as you do not want to remove the temper.-If you are replacing the spring do not be afraid to use a bigger torch and get things hot then discard, it speeds up the process--
-Once the allen key moves quickly remove the screw completely and immediately turn the firing pin itself out with the 3/8" wrench, a glove may be a good idea as things are hot and you must catch the pin so it does not launch when the pin is at the end of the thread (note, there is not that much force left at this point, it is just not a good idea to drop the firing pin)
-Thoroughly clean(wire brush) threads on both firing pin and set-screw of all old Loctite, clean/de-grease all parts with brakleen
-Let all pieces cool off then clean them up, assemble without the spring to ensure freedom of movement, record the protrusion at which everything moves nicely and free including "drop testing" this includes with set screw tight/snugged up
-Then re-assemble WITHOUT Loctite and set to your exact recorded protrusion this time with main spring in assembly
-2 drops of red or orange Loctite down into 5/40 set-screw hole, dab of same on set-screw and install to snug/tight.
-Test movement of pin, air blast inside shroud and let sit for an hour or two before assembling into bolt and testing to allow Loctite to set-up. After that time you may need to use the bolt tool or otherwise to "break free" the cocking piece from shroud as typically some Loctite escapes to this interface
-Drop of oil to soak between cocking piece and shroud, we recommend using moly grease on cocking ramp

[u/MoosedMilk → u/alexorange178]

Yup.

Unscrew a allen key, unscrew the threaded firing pin. Change spring. Screw in firing pin to desired firing pin fall. Check function. Loctite. And away.