Benelli M4 Recoil No More: Austrian Gunsmith's Recoil-Reducing Stock

Sebastian Unger is a good friend of mine and one I’ve had the rare opportunity to meet in person to talk about some of his designs - most notably the OpenTop 11/22. Sebastian recently came to me with yet another project he’s recently started working on. In a move that would make even the most seasoned gunsmiths shake their heads in bewilderment, our favorite Austrian man, tired of receiving his shotgun's punishing recoil, has decided enough is enough. Rather than suffer one more bruised shoulder, Sebastian has taken matters into his own hands and engineered a recoil-reducing stock that promises to tame even the most brutal of slug loads. Because when life gives you recoil, you build a better stock right?

More of Sebastian’s Projects @ TFB:

• The Rimfire Report: Fletcher Rifle Works 11/22 OpenTop Receiver Review
• AUSTRIAN TWIST UPDATE: Topside Takedown 10/22
• Revolutionary Rimfire: 3D Printed Receiver For Ruger 10/22 Style Rifles

Benelli M4 Recoil No More: Austrian Gunsmith's Recoil-Reducing Stock

Sebastian has been working hard lately on some pet ammunition projects of his. Since he’s been shooting a bunch of slugs lately, he’d naturally want to find a way to reduce the overall felt recoil of the ammo/shotgun combo so his shoulder wouldn’t be constantly subjected to the full power of a slug load. His homemade recoil-reducing stock transforms the normally sharp recoil impulse of the Benelli M4’s ARGO system with slugs into more of a push - drastically reducing the felt recoil on the shoulder. Sebastian has graciously provided us with a brief overview of his project so far:

Background of the design:

After developing the expanding copper slug and bringing it to production within the last 12 months, the recoil of the slugs always bothered me, I felt it in the shoulder for days after every test, so as soon as I had the time, I wanted to build a system that takes away the power peak of the recoil.

The slugs have a lot of inconvenient recoil because of their fast burning pistol powders, so the acceleration at the beginning is quite high. They also have a lot of mass inertia compared to rifle ammunition with the same energy levels.

Rubber Recoil Pads help a little bit, but overall they can just compress for a few 0.1 inches, which is not that much, so a better solution had to be created.

The basic idea of adding a spring in the stock isn't new, I just didn't find any comparable system for my Benelli M4.

I wanted to have a nearly endless stroke, so the firearm never hits a hard end stop and I wanted to see a large spring, so it looks different and it is visible what's really happening.

A commercial version of the design has to look different of course, but because this is just a hobby project, it is possible that it looks like that.

Sebastian likes to test his own projects pretty often and pretty rigorously. Below we can observe him running the same stock you see here in the photos through a number of tests demonstrating how the recoil-reducing stock works, as well as how it doesn’t work.

Features of the Design:

The stock is built from seamless construction steel tubes, the inner tube is a redesigned buffer tube, so all the Benelli internals can be used, the outer tube runs on the buffer tube and is centered with two steel pins. The two cutouts on the inner tube give the stock more than 3" of travel while dampening the recoil, so it never hits a hard end stop.

With the Tunet Commando Slug (440 grains - 1345 fps) the retraction is a little bit over 1", so there would be still room for using a weaker spring or much harder loads.

The felt recoil is greatly reduced, the harsh impact that hurt the shoulder is completely away, especially when the firearm is held very loose the difference is unbelievable. It makes no felt difference in terms of recoil of the firearm is pressed into the shoulder or if it is held relatively loose like a .22. The whole felt recoil is now like somebody is pushing against the shoulder.

The material cost including the threading taps and dies was below € 200,-- for the whole project and it works so well that I started to shoot slugs for fun.

Sebastian importantly noted that he’s not the first person to do this but he did need a solution custom fit for the Benelli M4. As far as I can tell, the stock he’s referring to that is already in existence and also uses a spring inside of its stock is the Phoenix Technology KickLite Recoil Reduction Stock. However, I believe they are only available for pump action shotguns like the Mossberg 500 and Remington 870.

I wonder if there might be a practical application for this type of stock when it comes to high volumes of slug fire - perhaps a competition shotgun might find this type of modification beneficial? Another application that might be helpful is during recreational clay pigeon shooting for those who don’t enjoy 12 gauge recoil as much as the rest of us. I’d, of course, love to hear your thoughts as I’m sure Sebastian would as well. Please let us know what you think down below!