TINCANBANDIT's Gunsmithing: Ruger Old Model Blackhawk Project part 3

Parts is Parts

Part 3 of this project (see Part 1 & Part 2).
While pondering my options I came across an auction on ebay for a brass grip frame from an 1851 Colt Navy revolver, which I won for the unbelievably low price of $22.50...

this made my choice even tougher. You can, believe it or not, convert these to work on a Ruger Blackhawk. Sharps40 did it on his New Model, converting it to an old model would be even easier...

In the end, I decided to restore the gun. I really didn't have the heart to cut up a classic old model. Maybe I'll find another one in worse shape to build a custom sheriff's model from? I can always change my mind later.....

I figured I needed an old model in my collection anyway.
Guns & Ammo journalist Patrick Sweeney listed the Ruger Blackhawk as one of the 10 Must-Have Handguns You Should Never Sell.
The Blackhawk was also in the book 50 Famous Firearms You've Got to Own: Rick Hacker's Bucket List of Guns.

The venerable outdoor mag Field & Stream also included the Blackhawk on their list of the 50 Best Guns of All Time

I am not one of those that follow every bit of advice given by the "experts", but this time I agree, this gun belongs in my collection.

This Blackhawk was made in 1972, the last year of the old model production.
Here is what the gun looked like before the restoration:

This project will require that I find a few more parts. Some people really enjoy this stage of a project, not me. I hate having to search high and low for parts for old guns.....
I did enjoy the research though and on this gun there was plenty to learn.

This drawing shows what I thought I was missing:

Fortunately, some of the parts are the same as the new model Blackhawks. The list of interchangeable parts includes:

Pawl plunger & spring (27 & 28)
Hammer strut, spring & seat (29, 30 & 31)
Cylinder base pin latch bolt, spring & nut (9, 10 & 11)
Rear sight screw (4)
Ejector rod housing, rod, spring & screw (17,18,19 & 20) I think there may be some differences, but they can be fitted

I could also send it to Ruger to have them update the mechanism with the transfer bar safety system.

Because this gun will be mainly a safe queen that sees the range once or twice a year and will never be carried, I think I will return it to the way it left the factory.

I just happen to have a good condition old model grip frame. The difference between the old model and new model (XR3-RED) is the trigger return spring and the cylinder stop spring. You can see my write up on this here.

This grip frame had the serial number of the gun it was originally installed on: a 1971 vintage 45 Colt Blackhawk.

Here you can see the trigger return spring hole

This is a new model ejector rod housing from a Single Six, you can see the turned down portion fits in the hole, but the hole is positioned closer to the barrel and thus the new model housing will not fit flush against the barrel.
According to some experts I consulted with they are supposed to be identical regardless of frame size or vintage.

Looking at the part numbers, the old model manual shows a part number of R-22, but it says in parentheses "Specify caliber", while the New Model part # is XR12200 with no caveats.
This catalog page from 1964 does show the .357 Blackhawk and the .22 Single Six to have different part numbers.

I do know that when I purchased a new steel ERH for my 10.5" New Model Super Blackhawk, the old aluminum one went on my Father's old model Single Six. The one we removed from his old model was reblued and installed on a New Model Single Six, the one removed from the New Model Single Six is the one that will not fit my old model .357 Blackhawk. So my only guess is that the mid-size .357 frame is the problem.

I will need to investigate further.
If I end up using a this ERH I will need to modify it to fit.
Back to parts searching......
I was lucky enough to trade an extra stainless cylinder base pin that I had for some old model parts. I got a hammer strut, main spring along with the trigger spring and plunger.

I was planning on putting the gun together for a trial fit before refinishing it. I discovered (I should not have been surprised) that more parts were missing....

The bag contained two sets (10 total) of grip frame screws for a New Model Blackhawk, also missing are the three action screws.
More research.....this time on the grip frame screws.
Consulting the manual, I found the original part numbers for the Old Model screws were:

Front: R-17
Rear: R-18
Bottom: R-19

The New Model part numbers are:

Front: XR01700
Rear: XR01800
Bottom: XR01900
Bottom Pivot Lock: XR01901

So the New Models use the same screws except for one of the bottom screws is different, it has the extra length to act as a pivot lock as well.

Because I have two of each, I am all set.

Some of the remaining parts I needed were available from Numrich Arms, this is my order:

I purchased this old model ejector rod on ebay for cheap...

I also did some research on the action screws. The hammer pivot screw is unique (larger), while the trigger and bolt pivot screws are the same (same part #s).
By looking at old manuals I collected the part numbers of the screws and discovered that the old model Single Six and old model Blackhawk used the same screws.
Then I found an auction on ebay for a set of Ruger Old Army screws.

The part numbers for the Old Army action screws are CB01600 and CB03400, while the old model Blackhawk (and Single Six) part numbers are R16 & R34, which leads me to believe that they will also interchange.

Fast forward---------->

All of the parts arrived and I was able to assemble the gun for a function & fire test. This proved my theory regarding the interchangeability of the screws and other parts. (in case you were wondering the blue tape is to protect the finish on the aluminum grip frame) from the screw driver(s).