Free Shipping & Free Returns*

FREE SHIPPING on Over 250,000 Products

Enjoy free shipping during the holidays! Shop now and get Free Value Shipping on most orders over $49 to the contiguous 48 states, DC and to all U.S. Military APO/FPO/DPO addresses.

Enjoy Our Extended FREE RETURNS

We want to ensure that making a return is as easy as possible! With our Hassle-Free, Extended Holiday Returns, eligible orders placed from November 12, 2025 on will benefit from an extended return deadline (January 13, 2026 or 30 days after receipt of your order - whichever is later). We'll even cover the cost of return shipping. Learn more about our Return Policy.

Shopping Cart
Stern Defense SD Mod4 M-Lok 9mm Complete Upper Receiver
$429.27 $419.27 Save $10.00
View Product
Compare (0)
Most Helpful Positive Review It's cool for an all-in-one 9 mm upper
I assumed that it was a dedicated 9 mm upper that it would not have a forward assist it seems as though they used some surplus uppers 4 rifle cartridge and just built pistol caliber uppers still cool just not dedicated more like a Frankenstein
Show
Sort by
Filter by

Feed Me More

by Joey C, Verified Owner from WI, United States Written on December 3, 2025
Second trip out today with this upper. Has eaten everything 115gr I have fed it; on-line remans, reloads, new brass, steel & aluminum. Not as loud as I expected. I assume the blast forward device helps. Only downside so far is accuracy. My groups started opening up at 15 yds & by 25 yds were beyond 6 inches. I realize 9mm PCC’s are not tack drivers; but D@mn. ALOT OF FUN HOWEVER!
Pros:
  • FUN FACTOR A+++
  • Eats everything
Cons:
  • Accuracy is questionable
Best Used for:
  • Fun . Speed practice
Would recommend: Yes
Was it helpful to you? Yes | No

9mm Complete Upper

by Sp33dy, Verified Owner from NH, United States Written on April 2, 2025
Great upper receiver couldn’t pass on a deal when it went on sale. Watched videos and reviews how well Stern Defense 9mm holds up and I was very impressed how sustainable the barrel is. After receiving my upper, I test it at the range and I was at awe. The quality, the smoothness, and precision was worth it.
Would recommend: Yes
Was it helpful to you? Yes | No

great to shoot

by jimbo, from TX, United States Written on February 12, 2021
Great to have and fun to shoot. Small light weight and versatile. Using if for multiple applications either hunting coyotes or training. I’m in love shooting it but since ammo is rare and hard to come by I haven’t had much play time lately.
Pros:
  • light but solid
Cons:
  • None
Would recommend: Yes
2 of 2 found the following review helpful.
Was it helpful to you? Yes | No
There are no reviews that match your criteria. Would you like to review this product?