Wednesday, January 22, 2014

Ultimate Mosin Nagant Build

Ultimate Mosin Nagant Build

A while back, I published the "Mosin Nagant - Transforming a Legend" article and my email filled with questions and comments. Most were expectantly excited over transforming their own Mosin, however some cringed at the customization I had done to a fine piece of history.  Regardless of the commentary, the article has been one of my most popular articles to date. For those Mosin traditionalists, cover your eyes because this is an Ultimate Mosin transformation that required cutting on a piece of history with a bit of tinkering and tuning that leaves a freshly uncrated historic firearm unrecognizable as a Mosin

I learned a loads from that build and the final outcome was a resounding success with thousands of rounds of fun shot down range to date. This time around, I wanted to go all the way with an Ultimate Mosin Nagant build using all the best components I could find to make the Mosin feel and maybe even shoot better than even that original build.

I again started with a 1930's 91/30 Tula rifle which many consider to be some of the most accurate surplus Mosins made.  The price was far from the free rifle my buddy supplied before, but still a very affordable $129 from Aim Surplus, the purchase hardly broke the bank.  The rifle then patiently waiting for something fun to happen, but it didn't have to wait long.  

Once again to upgrade the trigger, I turned to Timney for its rather incredible match grade trigger. A Rock Solid scope mount was the obvious choice and I picked up one of their bent carrier bodies to provide bolt handle clearance with a scope attached. I also picked up a new production Rock Solid  firing pin spring which has been noted to improve accuracy and consistent detonation. At least from initial looks, the spring appeared to be a huge craftsmanship improvement over my 1930 vintage version.

Rock Solid now has two additional Mosin Nagant scope mount options; the original scope mount, and now a M91/30 Scout Rifle Mount and MI-24C extended rail scope mount modeled after the US Army's MI-24 E1 sniper rifle rail. The MI24C extends from the rear of the receiver for over 12" down the barrel and will have optional 90-degree offset Picatinny accessory rails available. Rock solid wanted feedback on both and sent me samples of each to test for this and other builds.  Rock Solid has smartly kept the receiver mounting holes all the same between all three mounts. This allows the builder to swap to a different mount at some point if they want to transform a "sniper style" build to a "scout rifle" style build.

Actually this entire crazy project was caused by Bluegrass Gun Stock who shipped me a new fuller featured model of their original Tactical stock I originally featured in the Transforming a Legend article. Typically they offer the stock in hard rock maple, however my version was solid curly maple. I had provided some feedback on stock design and some of my ideas such as integrated monopod and easy knob adjustable cheek rest were incorporated into the new SF (Special Forces) Tactical stock. You know how it goes, once you have one upgrade component, a new build begins almost involuntarily.

Both of these companies are delivering the pinnacle of aftermarket upgrades for the Mosin Nagant tweaker, tuner, and builder. Luckily they are working very closely together on the development of products. Even if you just want a scope mount or stock upgrade to your original un-altered Mosin, they have a host of products available to improve accuracy, reliability, looks, and enjoyment of your Mosin.

Rock Solid was the first to offer a real drill and tap scope mount for the Mosin which remains the most stable and reliable method of attaching a scope.  All other competing mounts simply attach using the rear sight mount as the mounting point which is not enough to support an optic properly.  For those fearing the drill and tap, I was recently introduced to Devcon 2-Ton Epoxy which I am positive would deliver a drill-free permanent mounting method for Rock Solid scope mount to a Mosin and is likely to actually be more secure than a screw mounted scope mount Even if it didn't hold, you could always still install via the drill and tap method. Rock Solid is also where you will find bent handle carriers which provide the clearance once a scope mount is used as well as pillar bedding, and other accessories designed to enhance accuracy.

Bluegrass was the first to offer a quality wooden thumb-hole target stock for the Mosin Nagant, however they have expanded that line to include a host of options as well as developed the Tactical and SF Tactical stock which is an amazing stock for the money. The company is working on a 10/22 target version of their Tactical stock which I am hoping to be first in line for.

The build was simple and relatively painless as before with the exception of some barrel crowning problems. The first task was freeing the Tula Mosin from its bondage to the original stock and then slipping it into the new curly maple SF Tactical Bluegrass stock. On the early original Tactical Stock versions, I had to epoxy in the two aluminum pillar mounts, however Bluegrass now provides the stocks with them already mounted. This is a good and bad thing. If your Mosin drops in and lines up you just saved about 2-3 hours of pillar bedding work, if not you will have about an hour of fitment tweaking that needs to be resolved via a drill bit which is the route I needed to pursue. After using a drill to correct the cant on the pillars for my Mosin, I was able to get everything tightened down for the test fitting. This is not the fault of Bluegrass but the result of the variances of handmade Mosins.

The action fit great in the stock, so the next task was assuring that adding in the Timney trigger did not require any additional fitting. The Bluegrass stocks are available pre-milled for the Timney trigger and safety, however it is always good to check to assure your Mosin functions as it should once tightened down.  In my case, I had one minute of Dremeling to assure the safety would properly function and the Rock Solid bent bolt fully seated. This is common due to the little hand made variances on the Mosin Nagant platform.

While swapping out the Rock Solid converted bent bolt handle, I also added in the jointly developed Rock Solid/C&R Surplus stainless steel firing pin spring. The spring delivers a consistent 22lb rate a little less than the original Mosin spring. The spring rate and design decreases lock time and increase primer strike ability and was specifically designed to work with Timney or modified/lightened triggers. Each spring is made using high quality stainless steel then load tested to insure spring provides consistent performance.

The Ultimate Mosin also received a several trigger upgrades. Using a match Timney trigger was mandatory from my perspective, however Rock Solid makes a Timney trigger shoe which further lightens the feel of the trigger and provides a more biathlon feeling trigger.  Hey if you are going to go ultimate you might as well add all the little touches as well.  With the spring, trigger and shoe upgrade the trigger feel is sublimely amazing.

For my intended purposes an original Rock Solid scope mount would have worked fine, however the new Rock Solid M91/30 Scout Rifle Mount and MI-24C extended rail scope mount peaked my curiosity and looked freaking cool.  Ths MI-24C requires a rear receiver hole to be drilled and tapped just like the original Rock Solid Mosin mount. Up front both of the new extended mounts join to the receiver via two holes drilled and tapped by the user and also mount to the rear sight base via a cross pin and alignment screw. 

In either case you simply remove the rear leaf spring sight by driving out just one pin but leave the base punned and soldered to the barrel. The scope base is lined up on the receiver and the alignment screw is used to level the base to the receiver. This alignment screw basically just assures there to just offer leveling and alignment support during installation.

At that point the two receiver holes can be drilled and tapped per Rock Solid's instructions. If you are terrified of drilling into a $129 rifle then I recommend considering a permanent mount with Devcon 2-Ton epoxy, but once that stuff is set it is technically welded in place. The last step is to drill the pin hole through the front sight mount. The best way to do this is to drill each size with an undersized bit and then re-drill with the correct bit that fits the roll pin. Dependent on your Mosin Nagant model, you may need to shorten the receiver mounting bolts as some to protrude too much into the receiver and prohibit full bolt movement. A Dremel with a cutoff bit is all you need for that task.

Once you have everything back together, smoothly functioning, and the action back in the stock, you can mount up your optic of choice. In this case I reached for the Bushnell Tactical 4.5-18x40 scope with a Mildot BDC reticle. This optic provides plenty of magnification and can take the Mosin to its accuracy limits which I have found to be around 1-MOA with surplus ammo that will hold out to about 400-yards if I do my part. Additional tweaking and tuning of ammo and the barrel can improve that further.  The Bushnell optic delivers excellent clarity and a $350 MSRP is very reasonable for this quality of optic.

After over three months of tinkering around with this build, I had hoped to already have the action of this Ultimate Mosin finished with something like a Melonite to greatly ease the required post range thorough cleaning and improve the looks a bit, but that will have to be another article. Technically I had the time, however I realized that I needed to get a bit more aggressive with barrel shortening than I had planned. An extra deep Russian factory counter-bore reconditioning was nearly 2” deep. My first chop and muzzle re-crown took the barrel down to 24” and it shot very well with results that matched my first Mosin build however it wouldn't fit in my safe so I whacked it down a bit more to 20” and re-crowned it again with my Pacific Tool & Gauge crowning tool.  I then got a little overambitious polishing and cleaning up the crown. This screw up delivered an appalling 8” 100-yard groups. Yes folks a bad crown will screw up accuracy more than anything else. After a 5th range trip still working our barrel issues, was forced to shorten by ½” and re-crown yet again. Although my work done in frustration was a bit rough at the range, the latest re-crown put me back into a solid sub-1.25” group range with surplus ammo at 100-yards.  In this case the original action and barrel may simply have been a bit more accurate than this Mosin, but that does not make this shorter barreled rifle any less fun.

Of note, I would not recommend going under 22” for the Mosin simply because all you end up seeing through the scope is a muzzle blast with a sub-20” barrel which slows follow-up shots. A shorter barrel woudl be fine if you have a machinist buddy who can deliver a perfect crown and thread the barrel for a muzzle brake to dissipate blast to the side and out of the shooters optic sightline.

As noted above, my Ultimate Mosin delivered accuracy a bit less ultimate than my first build, however I still hold out hope that a final precision re-crown will rejuvenate accuracy. Even with accuracy a bit less than MOA, this Ultimate Mosin still delivers a fun shooting rifle with surplus ammo with accuracy infinitely better than a freshly uncrated Mosin and part of that is due to the re-crown, Bluegrass Stock, and Timney Trigger. As with my first Mosin update, one of the most critical upgrades was the Rock Solid scope mount which allowed the mounting of the Bushnell AR-223 4.5-18x40 scope.  The Bushnell AR/223 allows incredibly clear shot placement and the precision to take advantage of all the upgrades.  The Bushnell Drop Zone 223 BDC reticle allowed consistent shots with my tins of surplus ammo out to the 500 yard steels.

Once I can get the crown set to perfection, the entire Ultimate Mosin action will go to WMD for melonite coating to ease cleanup.  Many would scoff at sinking over a $1000 into a Mosin however consider that I can shoot this thing all day for just $0.20 a round. Yes even in the midst of the 2012-2014 ammo shortage, I could still order up a 440 round surplus spam cans of 7.62x54R ammo for just $90.  In a time that .308 is $0.80 a round, in only 1500 rounds with this tricked out Ultimate Mosin build, ammo savings will pay for every component and along the way deliver more shooting, training, and fun. Ultimate Mosin indeed.

Mosin Tula 91/30 - Aim Surplus $129
Rock Solid Industries Mosin Nagant MI-24C 91/30 Rail System (Round Receiver)    $130   
Rock Solid Industries Mosin Nagant Stainless Steel Firing Pin Spring    $12.99   
Rock Solid Industries Mosin Nagant Trigger Shoe $12
Rock Solid Industries Mosin Nagant Bolt Body with Handle $70
Bluegrass Stock Company Figured curly maple SF Tactical Stock $360
Timney Trigger $98.99 Street
Bushnell AR Optics 4.5-18x40 Riflescope w/ Drop Zone 223 Reticle $220 Street

Buy it at and support

Rock Solid Industries -
Bluegrass Stock Company -
Bushnell Sport Optics -
PTG Pacific Tool & Gauge -
Timney Mosin Trigger -


Unknown said...

What scope rings are those? How tall are they?

Major Pandemic said...

Those were medium height, I do recall who made them.