Removing Ruger P85 MkII Rear Sight
Back lock screw out (1/16 Allen wrench), then drift it out right to
left.
There is a small coil spring in there (firing pin block spring), but
thankfully not under too much tension. It is held in with the rear
sight.
Original P85 Firing Pin Block
P85 Mk II Firing Pin Block
Notice that this version shows the original P85 with a simple
dovetail, while the P85 Mk II has a milled pocket to the center
front dovetail edge for Rear Sight Lock - P85 MKII V07900. It
doesn't seem right...
What the V07900 appears to be is a "gib lock" to hold the rear sight
in place, akin to the Williams Fool Proof Gib Lock. This could be
another good idea fairy thing that disappeared? Does not exist on a
303-1nnn P85 Mk II. YMMD.
Millett Base is Very Tight
From the Millett instructions:
"After clearing the lock screws, if excessive force is required to
tap in the sight, remove some of the metal from the base of the
sight by sliding the sight across a piece of emery paper." They
aren't lying. It can be so tight that even a 3lb hammer won't drive
it home...
OK, the material removal showed the base is high around the edges,
dished in towards the center...
Fit of Millet Series 100 Sight in Dovetail
The base of the Millett Series 100 rear sight does not completely
cover the cut-out for the firing pin block. There is about 1/32nd
gap between the base of the Millett sight and the edge of the pocket
for the firing pin blocker.
Drilling the front sight pins
(waiting on firing pin block spring)
Drive out the pins for the front sight with a 1/16th pin punch. Put
the Millett front sight in the slot, and use a small C-clamp or
place the frame on it's side in a vice in order to hold the sight
blade in place while drilling. You may want to start drilling on one
side, then flip the frame over, and complete drilling from the other
side.
Sources For Firing Pin Block Spring
Original manual P85 MkII KQ05600, firing pin block spring. Gunparts
does not have any (525130D).
SR9C KVS05601 (Striker Blocker Spring) might/should fit as well.
Numrich SKU:
1388260 (12 Apr 2017)...
Numrich does not show a firing pin blocker (AX02110) for the SR22.
"Item number 44 in the exploded view from the manual is the firing
pin blocker, which includes the spring. The spring is not a separate
part nor is it shown in any exploded view diagram. You'll need to
order part number AX02110. You'll get a new blocker AND a new
spring."
UPDATE: Ordered two SKU: 1388260 from Numrich. We'll see...