Miroku Firearms Mfg. Co.



We would like to introduce the manufacturing process of Over/Under shotguns.




    Finishing and adjusting


    Polishing and bluing


    Make the buttstocks


    Engraving work


    Assembly and final adjustment


    Final inspection






Gun Drilling

A straight hole is made in the base material (metal bar) of the barrel, using a dedicated deep hole drilling "Gundrill Machine".
The barrel is made of a material made of chromium molybdenum steel with humidity controlled to increase hardenness in order to withstand the high pressure of the explosive combustion gas.
This "Gundrill Machine" is manufactured by Miroku Machine Co., Ltd., a group company, and is used in various fields such as the automotive industry and semiconductor industry as well as gun production.

  • Bar materials for barrel

  • Gun drill machine

  • Bar material before drilling a hole

  • Bar material after drilling a hole



When drilling holes or cutting the outer circumference of the material, a slight bend occurs due to heat and cutting resistance.
The position of bending and the degree of bending are determined by skilled workers looking at a white board for inspection from the hole in the barrel and visually judging the distortion of the shadow inside the barrel.
They do not miss a slight bend that can not be easily judged by the general public.

  • A master looking at a board for inspection suspended on the ceiling

  • Re-bending work. If a bore presents any curvature/distortion, it is corrected with fine adjustment by bending


Rough polishing and soldering

After grinding the outer shape of the barrel using "honing machine", multiple components are combined into one using "silver solder".
By heating to 700 °C and joining the "silver wax", which contains a large amount of silver, our barrels become very resistant to heat and vibration when the bullet is fired.

  • Honing machine

  • Honing processing

  • Barrel material after honing

  • Combining two barrels together with wire for silver brazing


Barrel Chamber / Rib processing

On the barrel that is bonded with "silver wax", we process the part called the chamber that loads the bullet and the rib attached to the top of the barrel.
The rib has the role of reinforcing the barrel and the role of ray protection to prevent light from entering the eye when targeting the target.


Frame processing

We will machine the frame material made in the partner factory precisely with the manual operation.
Since the frame incorporates a gun firing mechanism consisting of small parts, high processing accuracy is required.

  • Frame material before processing

  • Machining

  • Manually check whether the required accuracy has been achieved

  • Precision machined frame


Finishing and adjusting



Adjust the interface between the barrel and the frame.
Since the joint surface is required to have an accuracy on the order of microns, a skilled worker uses a file and manually adjusts it to fit perfectly one by one.

  • Visually check how the barrel and frame are fit

  • Adjust the joint surface with a file


Polishing and bluing


Polishing work

The adhesive and the abrasive compounds are mixed, dried and buffed, and the cloth buff is coated with the finishing abrasive to polish the frame and the barrel surface with so-called mirror-finish.
This polishing work is carefully finished one by one by the craftsman's hand.



After polishing, metal parts such as frames and barrels are blued and then simmered with special chemicals to turn the parts into black.
Mating surfaces with other metal parts are peeled off with fine sand paper after bluing to improve the adhesion of the mating surface.


Make the buttstocks


Making the buttstocks / forearms

Due to its high strength, ease of processing and the beauty of the wood grain, walnuts are used for stock and forearmr.
Furthermore, either the American or the Turkish walnut are used separately to meet the customers' taste with different grain and texture.
The processing of the stock and forearm is conducted at the group company "Nangoku Miroku".

  • Raw wood storage warehouse

  • Walnut blanks before processing
    * Each walnut blank is carefully checked joints, cracks, and insect bite

  • Add profile line for machining on the stock

  • Machined stock after cutting along the profile line

  • Turning operation to shape

  • Checkering process on forearm

  • The machined checkering are manually corrected by skilled workers one by one to improve the appearance and grip

  • Manually polish the surface of the stock

  • Manually create a small decorative part

  • Mating portions between the stock and the frame are carefully finished one by one by the craftsman


Surface treatment and finishing

The buttstocks and the forearms are coated before surface treament to fill the pore to smooth out the surface.
By applying varnish or oil on top of it, you can express wood grain beautifully.

  • Color matching work of the stock and the forearm. It will be colored so that the color of both parts match

  • Completed stock and forearm


Engraving work



Engraving being arranged on each Miroku guns.
While using different engraving techniques such as hand-carving, roller, laser, etc., the craftsmen will finish with their own hands carefully.
The engraving work is carried out at group company Miroku Kougei.

  • Roller engraving work to the frame

  • Craftsman gives hand-carved engraving

  • Fine lines one by one, engrave while looking with a loupe 15-16 lines come in 1 mm intervals


Assembly and final adjustment


Assembly and final adjustment

Once all parts such as the barrel, buttstocks, forearms and frame are in place, assembly and final adjustment will be performed.
Daily strict checks at the manufacturing site necessary to protect gun quality and safety.
All guns are labeled and marked by the person who performed the work, so that if the final inspection found a defect, it could indicate who assembled the gun.

  • The stock and frorearms waiting for assembly

  • Adjustment work

  • Assembled gun


Final inspection


Visual and function inspection

Special inspectors inspect each assembled gun both visual ly and functionally.


Actual shooting test

All completed guns are fired with high-pressure loads, which have more gunpowder than commercial loads, to ensure gun safety.
In addition, the point of impact are measured with using the device,.
Make sure that the criteria are met from both safety and functional aspects.




Packing adn Shipping

If all inspections pass, the label is marked with an acceptance mark and will be shipped to various countries after packaging.

  • Arrange guns for packing

  • Guns are carefully packed with accessories

  • For customers all over the world