We are now accepting new orders. Please contact us by phone or submit the contact us form to coordinate order processing.

It has recently come to our attention that not all contact submissions were getting through to us. We have fixed the problem and apologize if you previously submitted a form and have not heard from us.

ALUMINUM TRIGGER HOUSING UPDATE : We are in the process of machining a new batch of aluminum trigger housings. Please submit contact form and ask to be added to the ATH wait list if you would like an ATH reserved for you.


As of August, 2015, SierraPapa is in partnership with AztechArmory to provide our parts to Canadian customers. Please contact Marshall and Carol Ann Witzel at Aztech Armory for assistance with your order. 

SierraPapa now has our 07 FFL

SierraPapa is now legally able to receive your CX4s and perform a variety of gunsmithing work, including our new Flat Top and Collapsible Buttstock mods. As always, we do NOT need your complete firearm or even your lower to install our Hammer/Trigger/Spring Kit-- just send in your housing as per these instructions.


At SierraPapa we provide the aftermarket parts that make the Beretta Storm CX4 into the carbine it deserves to be. Since our aim is to "improve the breed" we only supply CX4 Storm parts and accessories of superior design and the highest manufacturing quality. We welcome suggestions from users for the improvement of our present products and any recommendations for new Beretta CX4 accessories that you may wish us to introduce.


Please read our Safety and Reliability announcement, and view this video that will guide you through the process of removing your trigger housing and shipping it to us. 

Please read our Warranty and Terms of Sale