Manurhin MR73 project

Manurhin is a French firearms manufacturer probably best known for their PP and PPKs manufactured after the war under license from Walther. However, they are also known for designing and manufacturing what some people say is the worlds finest combat revolver- the MR73. Here is an excerpt from the Wikipedia entry:

The MR73 was standard issue with France's Gendarmerie and in some police units including Special Weapons and Tactics teams (RAID, GIGN and comparable units).
The GIGN selected the MR73 in part for its ability to almost indefinitely withstand 150 rounds of full-power ammunition during daily range practice. These teams also use MR73's with scopes and 8" and 10" barrels for tactical purposes. Over one million rounds were allegedly fired through one example.

Every MR73 is match grade accurate, shipped with its own factory test target fired at 25 meters. Averaging 15 rounds, no group over 20mm (0.8 inch) diameter with selected ammunition is allowed.
The MR73 has an adjustable trigger weight in both double-action and single-action modes- a feature not found in any other revolver. These adjustments do not alter the strength of the main spring, ensuring reliable primer ignition. This is due to the use of roller bearings in the trigger mechanism along with extensive hand fitting and polishing of components during assembly. The MR73 requires more than 12 hours of hand-fitting at the factory, making it about 50% more expensive than competing U.S.-manufactured brands.
The revolver can be converted to 9mm Parabellum with a supplied replacement cylinder.
Cylinder chambers are finished with an impact process that makes them glass-smooth and extremely hard. The factory proof-fires each cylinder chamber with .357 Magnum ammunition generating 30% more pressure than the C.I.P. maximum allowable pressure for the Magnum cartridge. The factory guarantees that the cylinder will not burst or show any bulging or deformation with .357 Magnum ammunition developing double the standard maximum allowable pressure of 300 MPa, meaning the cylinder can withstand 600 MPa (92,800 psi, or 46.4 tons per square inch).
The frame, cylinder, and barrel of the MR73 are made from ordnance-certified, alloyed steel. Barrels are manufactured by cold-hammering. The rifling is formed during the forging process, eliminating the need to cut the rifling as a separate manufacturing step. This creates an extremely hard and microscopically smooth internal barrel surface.

I have always wanted to find one, but they are so rare in the US the prices were astronomical. Luckily, CAI was able to import a bunch of police surplus and the cost was reasonable. Although well used, the example I got is extremely accurate- if a little loose in the lockup and endshake departments.  The grip is very comfortable but absolutely ugly- also much too large for concealed carry.

After taking the sideplate off and examining the inner workings, I came away impressed. Manurhin's goal was to improve on Smith and Wesson's K frame, and in some respects they succeeded. It is more complicated, and difficult to manufacture- but the geometry leads to a shorter, heavier cocking action with a smoother trigger at a comparable weight of pull. A lot of this has to do with the rebound slide running on bearings and the adjustable main and trigger springs.

You can see in this picture how the original straw coloring of the trigger and hammer have faded. After going through it and cleaning it up, hammering then filing out any random dings and cold bluing the resulting bare spots- I decided to make myself a set of grips. Woodcraft provided the block of Osage Orange:

I then cut it into slabs and began inletting the backside to fit the frame. You can see that I JB welded some washers to the back to key into the cutout in the frame.

 It took quite a bit of rasping and sanding, but I ended up with exactly what I was looking for. I trimmed down a stainless screw and added a brass insert for the grip screw. Afterwards it was 4 coats of Tung oil with 2 days of drying between each coat. The Osage Orange was a pleasure to work with, it held together well during routing and sanded smooth. It has a lot of oils in it and some consider it the American equivalent of Teak.

 

The last shot is a before and after, you can see the new grips are much lower profile. The next step was to bend out a slight kink in the trigger guard then work on re-straw coloring the hammer and trigger. I attempted to color them in the oven, but I found a propane torch worked better in the end. I heated the parts up until they began to turn yellowish, then quenched in water. There is a finesse to this as the larger surface areas need more heat and vice versa- once the color change stars, it comes on quick and doesn't stop until quenched. The colors go from light yellow to straw to bronze to purple to dark blue to light blue . You want to make sure the pieces are quenched to keep them hard (and arrest the color change) as opposed to letting them cool naturally which may anneal them. I'm not a metallurgist, but I don't think the temperatures involved require re-tempering. Here is the end result:

 

 

I may have a try at rebluing this revolver eventually, but in the meantime- I will enjoy carrying and shooting it. It is tremendously accurate and I enjoy the work that went in to it as well as the history behind it.

 

 

 

 

 

Restoring old leather

This holster came to me via a little horse trading, fitting I suppose. $5 grips picked from the bargain bin and resold at a 800% profit got me enough spending loot to pick up this worn but incredibly detailed western holster:

 

 

I estimate it to be 60's vintage, the hand tooling is impressive- I can't imagine what it would cost to duplicate in todays dollars. It looks to be made for a 4-1/2" to 5-1/2" Ruger single six or Colt new frontier (or scout)- the loops are definitely for .22 rounds. When I received it, I got to work gussying it up with 2 products: Kiwi black shoe polish and Neatsfoot oil. Using an old toothbrush I scrubbed in the shoe polish to any places where the tooling or age had worn away the dye (cows are not black) and let it sit. Then I rubbed it in and polished it out. Afterwards I rubbed in about 3 coats of neatsfoot oil which is a leather preservative. This stuff is made from boiling down the shin and foot bones of cows which have a special kind of fat to keep cow ankles from freezing...seriously. It works real nice on any thirsty leather and is pretty cheap and easily available. Here's a half and half photo (polished and oiled on the right):

And the finished product, it's really night and day from how I received it:

 



 



Ol' Rusty

In your lineup of firearms there is always one that pulls the shortest straw, and is the first to go when something new and shinier comes along. In this instance, I was frustrated because I could not personally get along with the Ruger speed six (project detailed below). Though I carried it in the winter, I never was able to shoot it as accurately as I prefer. It was time to find it a new home where it would hopefully get along better with it's new owner. I worked out a trade locally for a poor neglected S&W 66-1 that looked like hell. I know I can shoot the 4" K frame platform well so I took a chance. The stainless had rusted and pitted severely- Yes stainless can rust if not taken care of. It had a nice trigger and Ahrends grips which needed a refinish. I took it to the range and it shot and handled nicely, but the heavily pitted yoke concerned me so I didn't put any 357's through it. [click on the pics to make them bigger]

 

 

Here are some pics showing the condition as I received it. Probably the worst looking stainless gun I've ever seen.

I've always been pretty good at sniffing out a diamond in the rough, so I got to work. Thanks to Ebay and Gunbroker I sourced a replacement yoke and cylinder in much better condition, total investment $70. I had to send back the first yoke because there are two different styles and apparently I have the less common one which is a little thicker up top. Here is a comparison pic of the cylinder:

 

 

After receiving the parts, I stripped the revolver down to screws and springs and bead blasted the entire thing. Here's where things went haywire. I read that the stainless must be allowed to repassivate- which means the outer layer of molecules exchange iron for chromium and form a protective layer. So I covered the rinsed parts in Bartenders friend which contains oxalic acid (I've used this particular acid to bleach wood in the past) which is supposed to speed up the passivation process. Well- it stained the stainless (which was looking quite nice beforehand) and made it look awful. My patience was wearing thin, so I took the parts and re beadblasted them and then immediately rinsed them and soaked them in CLP. I have some citric acid on order which is used commercially to passivate metals, so later on I will do a stain test and possibly strip the gun down and boil it in the dilute acid. Here are the after pics, the finish is very similar to the factory S&W blasted finish on the Performance Center guns:   [click on the pics to make them bigger]

I'm pleased with how it came out. I threw on the Herrett cocobolo grips that were living with my Model 18, because I like the Orange/gray color combo. Range report soon...

 

Rust bluing at home

The object of this endeavor was to give the revolver discussed below a durable, consistent finish without obliterating the character or original stampings. Rust bluing was the original firearm finish, it is so labor intensive though, that "Hot" bluing was invented to replace it. Hot bluing involves caustic chemicals that will seriously hurt you and eat through anything, but give a quick and attractive finish. After imagining my daughter finding a bucket of salts and it eating through her arm like Alien blood, I decided to try rust bluing instead. It is a more durable finish than hot bluing, but not quite as shiny.

This firearm came to me with a patchy, inconsistent and worn patina which is fine but I think it deserved a new lease on life. I shot it once with the thin grips it came with and struggled with accuracy. As I begun the refinish, I dug through my parts and came up with a period correct set of diamond magna grips and nicely case colored trigger. In addition I sourced a hammer of the correct design, as this particular kind was only made for a couple of years.

First order of business was to strip the original bluing, so a soak in regular vinegar to remove the remaining bluing.

Then a bead blast with fine glass particles to clean the rest of the crud off and give a proper tooth for the bluing to stick.

I then boiled the parts in degreaser to leech out any oil left behind, greased the bore and chambers and a quick wipe with acetone.

For this process I used Brownell's "Classic rust blue", swabbed on with cotton balls held in forceps. Small parts such as screws and the thumb latch were boiled in the stainless contraption shown in the picture (flea market buy- could be used for tea or something originally?)

After the parts are cleaned and degreased thoroughly, the bluing solution is swabbed on, left to dry for an hour, then swabbed on again. The parts are left to sit and rust in a humid environment for 24 hours.

This leaves a coating of red oxide (rust) on the parts, the next step is to boil them for 30 min converting the red oxide to black oxide. I used stainless steel wire and a dowel to suspend them in the stainless pot (pot sourced at local Goodwill for $5, later found to be a $200 French stock pot 0_o)

Very shortly after hitting the boiling water the parts begin to turn black. After the 30 min of boiling, I took them out and flash dried them with a hair dryer.

The parts are covered in a velvety black substance that needs to be "carded" off. I used 0000 steel wool and it took about 2-1/2 hours to card the parts to my satisfaction each time. The solution is then applied again and the parts are allowed to rust for another 24 hours. I repeated this process 6 times total, each time the bluing got darker, shinier and more homogenous. Here are some pics of the rusting in action:

 At this point I had over 20 hours invested. The steel wooling process is extremely tedious- I can't say I would recommend this process unless you are very patient and dedicated. Needless to say, I was overjoyed once the week had passed and I could start wrapping it up. Here's what everything looked like after the final carding:

I soaked the parts in a baking soda and water mixture to neutralize the bluing chemicals.Then a 2 hour boil in used motor oil (the carbon in the oil bonds to the freshly blued surface imparting more durability), left to cure for 22 more hours in the oil. This was the hardest part, I wanted to see it done!

After removing the parts, cleaning thoroughly and spraying down with eezox (rust preventative and lube) I reassembled with the new hammer and trigger. I also replaced the extremely worn hand that was contributing to some carry up issues (see post about carry up somewhere below)

Here are some before pics:

Note the patchy brownish finish and black rusty condition of the hammer and trigger. As a side note, I had considered re-case hardening the hammer and trigger, but it requires a forge capable of 1400 degrees (and a pyrometer to check it) which I do not have. maybe sometime in the future I will build one.

Here is the finished product:

You can see the finish is sort of a bluish black satin color, shinier than the matte finish of a model 28 and just a bit duller than the low polish of my 38/44 outdoorsman. The hammer and trigger have nice blueish purple and straw colored case hardening and the revolver is now wearing the correct post war diamond magnas (much easier to hold on to). You can still see the various dings and wear that I did not sand out of the metal, but is bothers me less than the rounded edges and scrubbed stampings would (The pictures show quite a bit of lint from wiping it down). I took it to the range today, and I shot it pretty good for a fixed sight revolver. It is very light and handy, the trigger is exceptional in SA and DA. Here's some targets I shot at 10 yards offhand (4" of black): There are six shots on the left target, can you spot the last one?

Overall a satisfying project, but I don't think I would do a whole revolver again, maybe a rifle barrel or slide perhaps?

Pre-model 10 Mystery

Finally reached the end of the bluing process for the pre-model 10. Assembly pics will be posted soon- In the meantime I'd like to discuss the history of this interesting revolver.

During the process of looking for a pre-war or Victory model K frame in 38sp, I came across this pre-model 10 for sale (to be exact a "M&P model of 1905, transitional") for a very reasonable price. I normally wouldn't jump on something like this, however the stampings on the latch side intrigued me and I couldn't pass up a good mystery.

 

After receiving the firearm from my FFL, I began to research the meaning of the markings and date of manufacture. This revolver was made in 1946, just as Smith and Wesson was transitioning back to civilian production. The Kanji markings as illustrated below-

 

roughly translate to "East (capital) Public (safety)" (thanks to the folks at Sigforum for help with the translation). Tokyo is otherwise known as the east capital (Kyoto being the old capital of Japan). I could not find any other records of revolvers marked as such, but my feeling based on the evidence is that these were sidearms lent or issued to the police forces in occupied Tokyo while being overseen by the Americans. The history of modern Japan is an interest of mine, esp. after the (happy) mistake of signing up for a grad level history course on the topic in college. The occupation was a very interesting time, considering how the two sides managed to cooperate and put the pieces of Japan back together in such a relatively short period of time.

This particular revolver has been around almost twice as long as I have and has seen a lot of things, I'm sure. The condition is worn but not abused- The finish is patchy but not pitted, I will discuss the refinish in the next post.