Scoping the Benelli Nova Shotgun

The Benelli Nova shotgun’s aluminum receiver bridge is covered by a fairly thick layer of plastic. It has a grooved flat surface across the length of the receiver that serves as a good place for a one-piece scope base, and, in fact, there are scope bases specifically made for the Nova model. So when a customer brought me his Benelli Nova shotgun with a number 428M one-piece Weaver base, I gave things a good look. He wanted a Red Dot sight installed on the shotgun, which is a good choice for slug shooting.

This sight fits the Weaver base, locking into one of the cross slots. On close inspection of the gun, there is ample aluminum thickness for scope mounting. The plastic coating over the receiver’albeit quite thick’offers no appreciable threadholding strength, but the cast aluminum beneath it is more than ample for the #8-40 screws. The Weaver base is equipped with four #8-40 slotted 82degree flat-head screws of 0.585-inch length.

Only two of these screws can be used at full length, as the two rear screw holes must be tapped. The front two screws must be cut to 0.419 inch overall length to avoid contact with the barrel shank. There is sufficient aluminum material for thread depth for these two shortened screws. Mounting the Base The procedure I followed was to mount the receiver in my milling vise, and use the drill chuck for drilling and as a tapping guide.

I used a center drill for precise centering of the screws, maintaining linear travel of the milling bed to position each screw hole. A #28 drill was used as a tap drill for the #8-40 base screws. The two front screws, as mentioned, were shortened to an overall length of 0.419 inch. These screws must be inspected for length after each one is tightened. To avoid weakening or stripping the threaded holes, the screws must not be over-tightened in the aluminum receiver material.

As a word of caution regarding tightening screws in aluminum, the following guidelines area good place to begin: Any #8-40 screws in steel would be torqued to about 27 inchpounds, while an #8-40 screw in aluminum should be more like 15-20 inch-pounds. This, of course, depends on how many threads are tapped in the screw hole. As a rule of thumb, the minimum thread depth in steel should be equal to the diameter of the hole. In aluminum, more is better.

The average person’s hand strength is sufficient to break a base screw or strip the threads in steel, and certainly it would be easier to do in aluminum. Common sense goes along way here. While I did not use a thread-bonding com-

This mounting system provides a rigid, trouble-free system that stays sighted under extreme hunting and shooting conditions. Conclusions Normally, scope-base mounting on a shotgun poses no problems. However, shotguns with aluminum receivpound such as Loc Tite, it certainly would be a good idea where a heavier scope is mounted on a shotgun with heavier recoil. I ers of varying thicknesses require more attention to detail. Threads must be cut cleanly and to full depth for the maximum screw-holding strength.

A one-piece base adds rigidity to the mounting system, and #8-40 screws are preferable to the commonly used #6-48 screws. Properly mounted, these mounts will provide years of troublefree service.