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Cavalry Manufacturing AR-15 Stock For Mossberg 500/590


Staff member
AR15 Butt Stock Adapter and Optics Mounting Platform for the Mossberg 500/590

In many ways the SST-590 is similar to the SST-870, but there were several design changes to make the concept more suitable for the Mossberg platform.

What is the same
1) T6 Aluminum Billet construction, Type III milspec hard coat anodizing
2) Designed to use optics effectively on your shotgun, existing iron sights cannot be used.
3) The docking port for the rail is the same as on the SST-870 so any future accessories will work with both units.
4) Allows the mounting of any AR15 buttstock and pistol grip.

What is different
1) The trigger reach is longer than the SST-870 (and longer than an AR15). This was unavoidable for 2 reasons;
a) cost of machining would have been greatly more expensive to position the pistol grip farther forward
b) for ambidextrous access to the slide release

We believe it was more important for the shooter to be able to put their finger behind the trigger guard to activate it. As the result of this longer trigger reach, grips such as the ergo grip and Fobus G27 grip may not work well for some shooters as the trigger reach will be too long




The Original Sheriff
Global Moderator
I've looked at these before. Even with the extension for the safety, I'd have a hard time with a high tube on a Mosssberg. I think I could rock it on a sight dedicated gun though!