Folks, going to form 1 my Benelli M1S90 and buy the 14" M2 barrel. I'd really like an extension tube that is flush to the front. I might could live with slightly shorter, can't live with slightly longer. Anyone aware of one that is the right length? By my math, the Nordic (my preferred brand) +2 is going to be about an inch too long and the +1 is way too short. I emailed them. I understand how the math works with regards to needing certain increments to get additional shells, but my logic is that if I was going to get a +1 anyway because all the +2s were too long, I'd be fine with a +1 that was longer than necessary to sit flush.

I've checked Nordic, GG&G, and a few random other ones. Seems like the 14" barrel is so uncommon, and most agency guns come with the factory extension that sits well short of the muzzle, that no one has made a flush extension tube. I guess my only option is to custom make one?

Edit: as I thought through this, I also thought that maybe the best solution would be to buy the extension I want, like the Nordic +2 and nut, install it, and then send the barrel off to someone to do a custom length cut. I imagine I could have the front Ghost ring setup removed, the barrel cut, and rethreaded for probably cheaper than a new 14" barrel costs. Downsides to this include not having the factory 18" barrel available and I may not be able to use the Agency Arms MLOK forend I wanted. The forend is supposedly only for the M2 barrels. While the M2 barrel works on the M1, Benelli says you need an M2 forend to go with it. I assume it's because the M2 barrel profile is different in the handguard area (thicker?). I'll email Agency Arms to see if they have tried their forend on an M1.

Can't help you on the mag tube length, but there's a guy on the Equipment Exchange selling used but good condition 14" M1 barrels for $225 last I looked. If you go with an M2 barrel you'll also need an M2 handguard.

I did the opposite and put an M1S90 entry barrel on my M2. I don’t recall have to modify the handguard.

I’ve considered mag extensions and short of trying to make my own, would have to live with either being slightly longer or slightly shorter. More function over form if anything. If an extra round is of the utmost importance, it’s tolerable being a little longer on the bottom end

As for the barrel, it was very cost prohibitive to get work done. Worked out better to sell the 18.5 and buy the 14 for a dedicated SBS. Almost cheaper to buy an older, used M1 if you want the longer option in your stable

Thanks everyone. I agree with everything said. So a few updates. Cotton Branch quoted $450-500 for a chop, rethread, and reinstall of the front sight. Yikes. The new M2 barrel is not threaded at $495.

I've got another M1 that's rifle sights and threaded. 18.5" with the flush +3 Nordic extension.

So far, plan is to leave it 18.5". I ordered the Agency Arms Forend. They confirmed it fits. Also found a stock local that was brand new, the 80045. Had to order the rear install shims from Midwest Gun Works. Probably won't be here for a few weeks.

So build will be 18.5" barrel, Agency Forend, Nordic +3B, and 80045 stock until I can figure out how I want to do the 14" barrel. I may just buy the 14" M2 and deal with the wait of the Form 4.

I was thinking. If you buy the +1 extension, can you not measure how short it is and have a local machine shop weld on a custom length extension onto your +1 extension? Since you are not cutting the +1 it will still provide you the +1 shell count but, will be flush for the look you want.

Yup, but I think it'd be easier to trim the +2 down. Simple cut and rethread. Especially the MXT tube since its separate from the nut.

Here's my 14" M1 barrel with an M1 mag tube and extension. I believe both parts are from an M1 entry model, but not 100% positive. I did have to replace the factory threaded portion on the stock mag tube to fit my Beretta receiver, so the length on your gun would be a little different.

Attached File

How did you get the collapsible stock on a M1? Or is this a Beretta and will the collapsible stock work on the M2?  I'm SBSing an M2 using an M1 barrel.

He posted in the pic thread. It's a hybrid build.

Watch gunbroker, i picked up a second 14” barrel to go with my 10.5” barrel on my M1 for 150.00

They are.
My factory M1 Entry has those 2 parts.

Very cool build!