Installing Millett Series 100 sight on P85 MkII

Ruger P85 & P85 MkII Manual Safety Model Pistols 
P-Series - P85 - P85MKII Pistol (manufactured from 1987 to 1992) Product History


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)...

Brownells: 780-722-112WB Striker Blocker Spring Mfr Part: KVS05601

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...