Scout_21

https://www.benelliparts.net/products/benelli-m4-14-sbs-short-barrel

Except for the 922r trigger kits and charging handles I believe so.

Unfortunately nature of the beast. I have 3 m4s and the engagement differed between all three. It must be a pia to try to design something that can deal with such a large variance

I can't really tell what's going on with those pics. Here's a good vid of taking down an m3

It's the magazine tube spring retainer https://www.midwestgunworks.com/page/mgwi/prod/60407 It would be number 67 on that above schematic for your shotgun. Other m3s have a disk. I do not know why this one is open and has that lip but I think it has to do with the limiter Also see here and here

Oh, that's not mlok on the spas-12. Its venting slots in the heatshield. It was a convertible shogun (pump and semi) and anything mounted in those sections would have interfered with the pump action.

Photos would help. Any chance these are what you’re describing? https://www.shopbenelli.com/stock-adjustment-kits.html

I'd certainly be interested in a SBS version

Not sure if this really helps but have you checked for any rough patches or metal slivers on all the cycling components? I’d probably do a full check on the argo pistons, bolt carrier, machining in the receiver, and remove the spring from the recoil tube to check those associated parts out as well. How does your follower look from the magazine. Any odd wear marks? I’m probably not adding anything you’ve already done though…

Ah, for a variant of the m3a1. Those probably won't have spare bits for quite some time seeing as Australia Defence Department just selected it for their shotgun.

do you mean this info https://www.benelliparts.net/products/benelli-61171-supernova-collapsible-stock-mr1 https://www.benelliparts.net/products/benelli-supernova-or-mr1-5-position-recoil-tube-1

https://www.swatmag.com/article/heliborne-shotgun-snipers/

I really like Vang Comp's elastic https://www.vangcomp.com/product/spare-carrier/ I honestly haven't found any better Just need some self adhesive hook and loop to put on the side of your m4 receiver

Freedom fighter tactical just listed some for sale… at the price of an entire shotgun.

Nice work! But why couldn't you do the same clamshell method of handguard assembly like the oem guard instead of needing screws to hold it together?