To place an order with Stern Defense, navigate through our products, add the items you want to the cart. When done, click the cart in the top right corner and follow the on screen instructions.

Currently, Stern Defense accepts: Visa, MasterCard, American Express and Discover.

After completing a purchase, you will receive a confirmation email to the email address you provided at checkout. Tracking and all relevant information will be sent to you automatically. Alternativley, you can "Sign In" to your Stern Defense account and view your orders. If you do not have an account please tap "Sign In" in the top right corner and then "Create Account".

Send us a message by clicking "Contact Us" on the navigation menu. Please include your name and order number in the message.

Thank you for shopping at getstern.com.  
We want you to love our products as much as we do.

ALL Sales Are Final.


Stern Defense offers you a warranty against defects in original materials and workmanship. If your Stern Defense product contains such defects, Stern Defense will take necessary actions to repair, or replace your product. Be sure to retain your original order number as a proof of purchase when making a claim.

What the warranty covers.

Stern Defense LLC products are warranted against defective materials and workmanship for 1 year from date of purchase to the original purchaser. Stern Defense's commitment to this warranty will be limited to, repairing or replacing products upon inspection and (on its discretion) found to be defective in material or workmanship. This warranty is limited and does not extend to: improper handling, unauthorized changes or modifications, misuse, abuse, excessive or senseless use, ordinary wear and tear, corrosion or obstructions.

The solutions provided by this warranty only extend to the original purchaser.

What we do not cover.

The warranty in this agreement is the only exclusive warranty related to the product. Stern Defense rejects any warranty express or implied, including but not limited to, warranty of worth or use for a specific purpose. Stern Defense, shall not be responsible for any damages resulting from any means, without limitations, delay cost, lost profits, regarding financial loss or injury to property or to third parties

How to return your item
You have 1 year to return an item from the date you received it.

  • Your item needs to have the receipt or proof of purchase containing the order number.
  • Please click contact us and send us a message. Please include your order number, name and what is wrong with the product.
  • Merchandise must be return shipped in a protective box

Inspection process
Once we receive your item, we will inspect it and notify you that we have received your item. If, after inspection, no defect is found or a defect relating to misuse you will be responsible for the cost of returning and repairing the item. We will contact you for payment and if no payment is received within 30 days we will restock the item and no refund will be issued. If the defect was caused by workmanship or defective materials we will repair or replace your product. This will be free of charge and the shipping cost to return the item will be on us. We cannot honor requests for returns out of the USA or if you have moved to a state that restricts the product we are returning.

You will be responsible the shipping costs to return your item.

Return your item to:
Stern Defense
5000 N. Highway JJ
Summersville, MO 65571












If you have a Colt style bolt and wish to use our system, we have a service that will make your Colt style bolt compatible with Glock magazines. For more information click the following link. Glock Cut Service  

Will it work with this magazine?

Although the MAG-AD9 works with many aftermarket magazines, we recommend using post 2004 square notch, Glock OEM magazines. As these will provide the best fit and function.




Please note the above picture, notice the lack of a ledge on the new magazine as compared to the old. Also please note the (SQUARE) shaped notch on the new magazine as compared to the (U) shaped notch on the far right magazine.

(U NOTCH) magazines are very early generation glock magazines, they were not fully metal lined and due to this they expand when loaded causing reliability and insertion issues.

2004 and prior magazines (SQUARE and U-NOTCH) also contain a ledge on the right hand side as noted by the above picture.

While in some situations these magazines can still be used with the MAG-AD9 series, they may require more force to seat the magazine or may not seat at all. Some very light modification can be done to the magazines to allow them to seat easier.  

We still do not recommend the use of U-Notch magazines, as even with modification, they may not work or be reliable due to the lack of a full metal liner and expansion when loaded.

If you want to use these types of magazines, you can slightly modify the magazine in order to fit. See figures 1 and 2 below.


Figure 1


If you have these older magazines and wish to use them. Please note the areas of the magazines that will need modification .  

Figure 2

If you wish to use these magazines, you can take a simple household file and bevel the indicated edges slightly ( green arrows as shown in figure 2.) This will allow the magazine to seat fully without excessive pressure. This should be done in small increments with test fitting and should not affect the use of the magazine in Glock pistols. DO NOT MODIFY THE AREA INDICATED BY THE RED BOX.

While we have experimented with this and have had zero issues. Stern Defense accepts no liability for modifications you make to your magazines, If you decide to do this you do so at your own risk.  


When building an ar-15, it is critical to pay attention to the length of buffer you are using and the length of the tube. Also note if spacers are required for the particular length buffer and buffer tube combo you intend to use.  

If proper procedure is not followed, this can result in a catastrophic failure of any ar-15 system by causing the gas key to be sheared off.

Please note how the gas key is contacting the lower receiver in the picture below. This is not what you want. There should be clearance between the lower and the back of the gas key.



While it is possible to use a standard weight carbine buffer with a PCC blowback system and in testing we have experienced no issues.

We still recommend the use of an H3 buffer or heavier for pistol caliber carbine systems. This increases dwell time and slows the travel of the bolt prolonging the life of your components. You can find an H3 buffer HERE



Recently confirmed.
This is not unique to our system but the pistol caliber carbine world in general. Based on communications with Geissele Automatics and personal confirmation. The Geissele Super Dynamic 3 gun trigger is not compatible with pistol caliber carbines. This is due to the trigger system having too short of a hammer.