Steve Rose

https://www.gunpartscorp.com/products/1438420 https://www.gunpartscorp.com/products/840750

Does your extractor look like this one?

The M4 bolt will NOT contain an inertia spring and will NOT have the slot cut underneath on the bottom right that prevents "ghost loading" of the M2 and SBE2 (most SBE and M1 bolts will not have this slot cut either)

On everything Benelli I have seen the front bead is threaded M2.5 X .45, which is so close to the common 3-56 that they are interchange. I doubt Benelli changed the front bead thread size on the B.E.S.T lineup.

The factory M4 can be threaded, we have threaded several of them.

It does look kind of rough, and I wonder what (lack of) pride in manufacturing lets that happen....but the appearance will really have zero negative affect on the cycling and function of the shotgun.

Activating the CDL should not drop the hammer, but dropping the hammer DOES activate the CDL. When you activate the CDL a shell is released from the magazine tube. Activating the CDL does NOT make the hammer fall or the gun to fire. When the trigger is pulled and the hammer falls the CDL is activated by the falling hammer (which allows a shell to be released from the magazine tube).

Briley has something close for your SBE3

Numrich Gun Parts https://www.gunpartscorp.com/products/1431420a

Take the trigger group out of the receiver and try to load a round into the magazine tube. Will the round fully go in? (You can expect a certain amount of resistance being required to push the shell's rim past the carrier latch)

It would appear that your bolt is just slightly out of battery, the extractor should rotate up to a 1:30-2:00 position. If the bolt is even slightly out of battery the shell lifter will not move up enough to allow you to insert a shell into the magazine tube. When you close the bolt are you letting it slam shut under its own spring power - or are you easing it forward by hand? (Let it slam shut under its spring power) The gap behind the cam pin (your 2nd picture) is normal. There is a strong spring inside the bolt carrier body that gets compressed under recoil and makes the “Inertia System” do its thing. You will not be able to compress that spring by hand.

Your DMW device is keeping the hand guard from fully seating which keeps the barrel forward by the same distance ...and hence the barrel cannot fully seat. Do these other bolt assist devices fit in between the receiver and hand guard - or are they the buttons or levers that attach to the small round button of the factory bolt release?

Unscrew and separate the barrel and and receiver. Clean and degrease the inside and outside threaded area. Make sure you can screw the parts back together. Separate the parts again and apply a liberal coating of red Loctite on the threads then screw the 2 pieces back together till the parts lien up properly then let the Loctite dry until tomorrow. I've seen 2-3 Benelli guns and a few Brownings over the years that have come loose as your has done.

Unscrew the sight and take it out of the rib. Clean off/degrease the threaded shaft. Add a drop of blue Locite (thread locker), fingernail polish or 5 minute epoxy on to the threaded shaft. Screw the sight back in place and lined up straight. Let it set and cure for a few hours.

The Nordic Components "+3B" tube is advertised as being a flush fit with the Benelli semi auto 18.5" barrels