Miroku MK70 shotgun
The mid 1990s marked a technical milestone for the Miroku factory in Japan. It was the era in which they launched the MK70, and to build it and its sister guns they dramatically changed their barrel-making methods.
In previous Mirokus the barrels had all been built on the chopper-lump principle, just like fine English shotguns. This meant each barrel and lump was forged from a single billet of steel, bored and polished, then the two were hard-soldered together to form the complete barrel set.
For the new guns, Miroku invested heavily in a new barrel-making plant which employed the monobloc principle, in which the two tubes of a barrel set are manufactured individually, then sleeved into a separate, forged breech block which incorporates the lumps.
Despite what the purists said, and still say, this method produces barrel sets just as strong as the old process, and it is much more economical and adaptable for the manufacturer. It is used by all of the major Italian manufacturers, and many others throughout the world.
In Miroku terms, the MK70 took over where their well-loved model 7000 left off. Shooters with long memories will recall the 7000 set a precedent of its own: it set the fashion for flush-fitting multichoke tubes in an era when most of the tubes had knurled ends which protruded from the muzzles.
Who makes it?
The Miroku factory is in the city of Nangoku, in Japan’s Kochi prefecture on the island of Shikoku. They started building sporting arms in 1893, and at one time made guns sold in the USA under the Charles Daly name. Negotiations which began their long association with Browning opened as long ago as 1965. For many years, as well as making guns under their own name, they have built all of the more affordable Browning over-unders. They also make machine tools and automotive parts.
How adaptable is it?
The sporter is suitable for all clay disciplines except trap. It is also light enough to double as a field shooting gun. All models now have 76mm (3in) chambers.
How does it work?
Like all Miroku and Browning break-action guns, the MK70 follows, in broad principle, the general design features of the immortal Browning B25, designed by John Moses Browning in 1925.
There are some differences, the most apparent being that Mirokus and Miroku-built Brownings, are not blessed (or cursed, depending on which way you look at things) with the B25’s sliding, non-removable fore-end.
As in the John Moses original, all the MK70’s mechanical components are stacked in a logical order, one on top of the other. The gun, unlike so many these days, also has a full-width cross pin to form the jointing. This pin runs beneath the barrels, which means the action is deeper than designs in which the barrels hinge on stub pins. This, in turn, means the gun has slightly different handling characteristics to, say, a Beretta.
At the bottom of the action lies a full-width bolt which engages with a sturdy bite in the barrel lumps. Hammers, which are hinged at the bottom, are driven by coil mainsprings. Sears hang from the top strap, and can engage with a second bite in the hammers should the gun be dropped or knocked sharply enough to cause the sears to drop off the main bites. This is a wise safety precaution.
When the top lever is pushed over to release the bolt, a cam forces the hammers back. This allows the striker tips to retract in order to clear the primers and allow the gun to open smoothly. However, only the lower striker has a retraction spring, while the upper one is free-floating. This sometimes causes consternation when a Miroku shooter looks at his open gun and sees the upper striker tip protruding from the breech face. In fact, there’s nothing to worry about.
Exterior decoration of the action depends on whether you go for field or competition versions, and which grade you choose. There are three grades of sporters – one, three and five – all with different engraving styles but one thing in common: all are bright silver on the outside. Field models come in just grade one.
– Miroku sporters and field models are offered with 28 or 30 barrel tubes.
– Side ribs are solid, while the top rib (10mm on sporters, 6mm on field models) are ventilated.
– 3mm white foresight is fitted.
– Chambers are 2.3/4 in (70mm) on competition guns, and 3in (76mm) on field models.
– Bores are internally chromium plated.
– Five flush-fitting multichoke tubes are supplied with multichoke models.
– Varies depending on the grade you pick, but all Miroku walnut is strong and very well fitted to the metal.
– The higher grades just have a more attractive grain and finish.
– Stocks on grade five models feature drop points.
– Sporter stocks are usually 143/4 in. at the centre, and are fitted with hard plastic buttplates.
– Sporter drops are usually about 1.1/2 in at comb and 2.1/2 in at heel. Some users think they shoot rather ‘flat’ – in other words you have to aim almost straight at a target rather than just below it. Sporters have Schnabel-pattern fore-ends, for which the term used by Miroku is ‘tulip’.
A typical sporter weighs about 7.3/4lb. As with all guns, weights obviously vary slightly depending on barrel length and wood density.
What the tester thought
Sporting Gun tested a second-hand MK70 sporter in April 2005. The gun scored 8 out of 10 for build quality, and seven for handling, styling and value for money. The gun’s reliability and the easy availability of spares came in for praise, although it was pointed out that, over time, firing pin tips could be prone to cratering. Spares, however, are available and easy for gunsmiths to fit.
From around £1,200 for a Grade 1 Sporter up to about £2,300 for a Grade 5.
UK SALES: 01235 514550
Similar model Brownings fall into a similar price range, as do most Berettas featuring the ‘600’ series action.
From all Browning/Miroku dealers.