I'm back again.
a few pictures of the MK IV internals
bolt breaks down as MK III
guide rod assembly and firing pin are different...my bolt uses the same rebound guide and spring as MK III...mine does not have the rebound parts as shown in MK IV manual. Note: rebound guide re-installs with hump up
using a pin to push and hold plunger, then turn over and tap on bench..the extractor will drop out
extractor and associated parts
shows short leg position of mag disconnector spring
shows the long leg position of the mag disconnector spring
To remove hammer and associated parts remove right side safety lever with 1/16" hex wrench then push the shaft of the left side safety out retaining safety detent and spring.
assembly removed
pinch long and short legs of mag disconnector spring to open spring loop so hammer bushing can slide out easily
parts broken down
position of short leg of sear spring
position of long leg of sear spring
to remove sear & spring push sear pin out...parts shown with a slave pin installed for reassembly...to reassemble I used needle nose pliers to drop assembly with slave pin down
into frame guiding the long leg of spring into place and aligning slave pin with holes in receiver...then push sear pin in pushing slave pin out
to remove trigger press trigger pin retainer at arrow and push pin out left to right
bolt stop parts removal...self explanatory by looking at assembly
reassemble bolt stop parts and trigger in reverse using a punch to line up parts and push trigger pin in right to left
to remove barrel latch and mainspring housing push out pin at rear of frame...parts shown
to remove mainspring it appears spring barrel can be removed with a hex key (I didn't disassemble it)
to reassemble hammer, bushing and mag disconnector I used a 2 step slave pin process...
position safety into frame...push sear forward to engage hook on safety and insert a punch to hold parts in place
then place the trigger bar over the hammer bushing and drop assembly into frame guiding the long arm of the mag disconnector spring into place on the frame cutout as shown
previously...align with holes in frame and push another punch in from right side pushing the left side punch out.
now push the left side safety lever in pushing the right side punch out leaving space to install the detent and spring
now push left safety lever all the way in and attach right side lever.
if you want to get rid of the mag disconnect feature eliminate these parts upon reassembly...making the cut shown if you want to use as a spacer
then either snip the part indicated on disconnector to use as a spacer or use washer(s) with the same dimensions as indicated part as I did
assembled without mag disconnector parts
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