DMW Magazine tubes are made in two pieces. In that they attach to the end of the forearm instead of replacing the complete tube. These do not include the nut which should come with your factory benelli if it has an extension already. If you don't have an extension you will need the nut also. If you want a complete package including the nut please look at the Nordic product line. These include the cap/follower and spring. Great Thought and care went into these tubes to make them the strongest available.
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Step1 a special adhesive, rated at 300,000lbs. holding strenght, is applied to the end of the tube.
Step2 the tube is pressed into the collar with an interference fit of .001"-.002".
Step3 After proper cure time, the reciever end of the tube is wedged into a chamfer at the base of the collar.
Step4 The unit is placed in a lathe and the threads are cut, insuring concentricity of the threads to tubes.
Step5 The Muzzle end of the tube is rolled over to hold in the cap and spring.
Step6 The asembly is blasted with 200 grit Alox.
Step7 Assemblies are black oxide finished, cleaned, oiled, and packaged.