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12 Gauge to 9mm Shotgun Adapter

9mm 12 Gauge Shotgun Adapters

(7 customer reviews)


9mm Shotgun Adapters for 12 Gauge Shotguns

Adapters come in 4 Lengths

2 3/4″ 5″, 11″ and 18″

All Adapters are Fully Rifled with a 1-12 or 1-18″ Twist.

Select Length below: 
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9mm Shotgun Adapters for 12 Gauge Shotguns

9mm Shotgun Adapters Allow a 12 Gauge Break Action Shotgun to use 9mm Auto in addition to Luger Ammo.

For 3″ Or 2.75″ Chambers

Compatible with Break Action single as well as double barrel shotgun.

9mm Shotgun Adapters Heavy Duty Steel Construction

Rifled:  with a 1:16 twist rate for the 18″ as well as a 1:12 twist rate for all other lengths
Rifled dimensions are .355″/.349″ with 6 lands and .125″ wide.


9mm  Auto Shotgun Adapters Comes with multiple O-ring configurations.  As a result,  easily achieving a good fit for 12 gauge shotguns.


Black Oxide coating as a result provides notably better corrosion protection (for maximum corrosion protection keep a thin coat of oil on the insert)
Carbon Fiber (The Carbon Fiber is used for a cover and added stiffness It is not a factor in the strength of the all steel construction).

I recommend to keep a coat of oil on the insert for more corrosion protection


What are 9mm Shotgun Adapters?

Shotgun Adapters frequently called Chamber Reducers or Shotgun Barrel Inserts. Our shotgun adapters allow you to use other types of ammunition in a Break Action Shotgun. Including double barrel and over and under double barrels in addition to the popular single barrel break action. We offer several different versions to suit your preference in ammunition, as well as length. 12 and 20 Gauge shotgun adapters are our most popular adapters followed closely by the 410. 16 Gauge is something we plan on expanding in the future.


9mm Shotgun Adapters

Most of our shotgun adapters come in different lengths to suit your needs. Some like the secure storage and portably of Shell length adapters. Whereas some are looking to get the most fps (feet per second) or accuracy out of their adapter. Black Oxide has become our standard finish. We can offer unfinished adapters during our production if you have requested one.

FPS (Feet Per Second)

9mm Shotgun Adapters
As a general rule, the longer the adapter, the more FPS it produces. However, with low-pressure rounds such as the 45 colt, the fps difference is minimal once past the 11″ length. If you are interested, here is an excellent website that gives a good idea of fps per inch BBTI. All of our shotgun adapters are entirely made in the United States and are an affordable addition to your break action shotgun. Thank you for you interest in our Shotgun Adapters or Chamber Reducers. We are working to make more adapters for more calibers, so you can sign up to be notified here
The video below gives a brief demonstration of how they work.

We are working to make more adapters for more calibers, so you can sign up to be notified here. Thank you for your interest.


If you like 9mm Shotgun Adapters, check out our other Shotgun Adapters

Additional information


2 3/4", 5", 11", 18" With Carbon Fiber


Black Oxide, No Finish (Silver)

7 reviews for 9mm 12 Gauge Shotgun Adapters

  1. Charles Harsson (verified owner)

    Chad thank you very much i got your package, it worked i just wanted to say i greatly appreciate it & i will definitely be shopping with you & your fine adapters from here on out.

  2. Jesse d. (verified owner)

    9mm is a cheap round…. plinking fun for everyone

  3. Brian Blanchette sr (verified owner)

    Seems like a good value for plinking

  4. Charles Harsson (verified owner)

    Chad yes please that would probably work just fine I just ordered mine on the 8th of april so yall have my information.

  5. Charles Harsson (verified owner)

    I bought one of the 2 3/4 9mm-12 gauge adapters and it’s a really really tight fit in my nef single shot 12 gauge it has a 3″chamber so it should fit just fine, I also added a light coat of rim oil to the adapter but no luck it’s still a really tight fit, hopefully the more i shoot with it the more it breaks in and losings up in time….

    • Chaszel (store manager)

      I can will send you some slightly smaller O’rings to try if that is ok with you


  6. Michael (verified owner)

    Fits well. Shoots extremely accurate. I need to pry the 9mm luger casings out as they seem to case form to the 9mm auto chamber. A small flathead screwdriver suffices. It is not too hard at all.

  7. Robert Harwood (verified owner)

    By far the best adapters on the market. Even with just the 2 3/4″ I can shoot fist sized groups at 50 yards with open sights

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