12ga 357 maximum text 2

357 Maximum 12 Gauge Shotgun Adapters

(4 customer reviews)


357 Maximum Shotgun Adapters for 12 Gauge Shotguns

Adapters come in 4 Lengths

3″ 6″, 11″ and 18″

All Adapters are Fully Rifled with a 1-12 or 1-16″ Twist.

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357 Maximum Shotgun Adapters for 12 Gauge Shotguns

357 Maximum shotgun adapters for a 12 Gauge Break Action Shotgun allow you to use 357 Maximum as well as Magnum in addition to 38 Special Ammo.

For 3″ as well as 2.75″ Chambers

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


Rifled:  with a 1:16 twist rate for the 11″ and 18″

1:12 twist rate for 2 3/4″ and 6″


357 Maximum Shotgun Adapters Rifled dimensions are .356″/.347″ with 6 lands and .125″ wide.


Black Oxide coating as a result provides notably better corrosion protection (for maximum corrosion protection keep a thin coat of oil on the insert)


Please Note:  Not all shotguns are the same!  While the majority of them are capable of handling high pressure rounds, some are NOT.  Only use these rounds in shotguns that are compatible.  I recommend on any shotgun to test the first shot in a vice while out of harm’s way and to always wear eye and ear protection.  If after testing, you see the primer punctured in the round discontinue using this round and use a less powerful round. These high-pressure rounds include: 45-70 gov., 357 Mag Shotgun Adapters, 327 Federal, 44 Mag, and 22 Hornet.  Please always be safe and aware.
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What are 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.


357 Maximum Shotgun Adapters are a High-Pressure round.

However, not all shotguns are capable of handling all of the shotgun adapters we offer. Low-pressure rounds work in any shotgun, whereas high-pressure rounds can cause problems in some shotguns. The problem is when the firing pin punctures the primer. This event causes the gases to escape and possibly damage the firing pin. All adapters chambered for high-pressure rounds have red text on the website, signifying that is is a high-pressure round. These adapters also include a pamphlet with more information about this concept. In addition These Shotgun Adapters also have a Low-Pressure round alternative.


357 Maximum 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)

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 your 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 357 Maximum Shotgun Adapters, check out our other Shotgun Adapters

Additional information

Weight N/A
Dimensions 24 × 3 × 3 in

18", 11", 6", 2 3/4"

4 reviews for 357 Maximum 12 Gauge Shotgun Adapters

  1. Verified Buyer (verified owner)

    I received the 12 ga 357 Max 18” insert a couple days after I ordered it. Went to an indoor range and it worked great. It’s in a NEF single shot with a bead site and I was shooting 25 yards hitting what I was aiming at.

  2. Verified Buyer (verified owner)

    Works great , was shipped fast and came to me in 4 days

  3. james (verified owner)

    first rate quality and service is standard on all Chaszel products.

  4. Monte P. (verified owner)

    Super high quality piece. Can’t wait to try it out!! A+++

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