Effebi is a gun-maker company now also specialised in manufacturing a wide range of cold-forging rifled barrels, traditional tubes for shotungs and ribs. Effebi bought recently all the necessary tool machines to make this job and have planted them at it’s premises and to it’s joint-venture partners so to meet any custom request for these items. GFM cold-forning machineAre available the following technical equipments. GFM cold-forging machine to make rifled barrels in any caliber. Full sets of Holing machines to make sleeving tubes and chopper lumps as well as Honing machines for the perfect inside finishing. Utita numerically controlled lathe T200CN, 4 axis, for turning outside the required measurements. Grinding machine to finish the out-side part of each barrel. While for bored tubes we follow the traditional system, rifled barrels are made with the most up-dated system available. Barrel blank has to be spade drilled larger than the finished diameter. Before rifling the blank will be reamed and honed. Two axis holding machineA mandrel will be positioned into the bore, wearing the invers shape of the rifling on itself as well as the required twist.
Exactly where the mandrel is positioned the barrel blank will be forged by several hammers driven by the engine with huge power and velocity, until the steel touches the mandrel at its surface mirroring the grooves and lands on itself. The steel will be compressed, encreasing its strenght to about 10 to 25%. Milling the rear of chopper lumpsThe workman-ship results in a perfect bore, exactly straigth with truely shining face well resistant against deterioration from the elements. No further machining is required. This gives a well consistant precision to the barrel.
When specially required by customers or beeing not available the forging-mandrel for some calibers of rifled barrels they may be also made with traditional system with all the necessary working steps as: general leveling, makeready of the extremities for the drilling, drilling, reaming by three or four reamers depending from the caliber, cheking of the diameter thanks to plugging operation and visual control of the rough grade, passing through an ogive by pressing or by broaching or ruling machine, turning sleeving tubesfirst turning, exposition to controlled atmosphere when required by the caliber , refinishing turning.
Each one of the listed steps is followed by a leveling control. At the end of the working schedule barrels are exposed to an heat treating to spread the molecules and also exposed to a controlled atmosphere to bring the hardness over 90 KG.