Austin Custom Brass Backbores

(18 reviews) Write a Review
1.00 LBS
$3.00 (Fixed Shipping Cost)
  • ACB trumpet backbore blanks (from left to right: slug, heavy, heavy cut for sleeves, standard, standard cut for sleeves)
  • ACB cornet backbore blanks (from left to right: C1 heavy, C1 standard, C1s heavy, C1s standard)
  • Austin Custom Brass Backbores
  • Austin Custom Brass Backbores
  • Austin Custom Brass Backbores
  • Threaded backbore for Adams integrated receivers - special order only
"I own 4 different ACB backbores that the friendly staff at ACB helped me choose with specific tops as well. The quality is great and I have been in love with the ease and efficiency in my new equipment. I have better range now at age 45 then when I was playing all the time in my 20's. I love the flexibility that the backbores and tops offer me in different situations." -Derek Limback
Frequently bought together:


Austin Custom Brass Backbores

ACB backbores are now in stock!

All ACB tops and backbores utilize the now universally accepted "Warburton" threads, making them compatible with almost every other maker's modular components! Check out our mouthpiece sizing spreadsheet to see which backbores come standard with our various one-piece mouthpieces. If you want help choosing a backbore for your particular playing needs, please call our Mouthpiece Hotline at (781) 816-9664 and we'll be happy to assist you!

ACB backbores are designed to be as acoustically efficient as possible. Currently I have many different tapers available!

Standard backbores

Here are our standard backbores, from high compression commercial backbores to wide-open orchestral backbores:

  • KA3: Our newest commercial backbore and it is amazing! Feels almost like the throat is one size smaller due to the compression.
  • KA2: A very nice backbore with good zing.
  • KA1: More core than the A2 and a bit tighter as well.
  • A2: The A2 is a weapon!  Designed to be mated with compression mouthpieces. 
  • T (Tight): commercial backbore which provides the most resistance and "zing"  to your sound
  • MT (Medium Tight): Provides great resistance, especially for players who tend to "backup."
  • S (Standard): Provides the best balance between resistance and sound spread for most players. 
  • MO (Medium Open): A great slightly open symphonic shape produces a rich, warm tone but still gives ample resistance when needed.  
  • A1: This backbore is a very large, symphonic backbore that is in between the MO and O – a wonderful backbore suited for the classical player or jazz soloist wishing for a large sound!
  • O (Open): This is a very large, open backbore designed for the orchestral musician to provide the feel and sound spread that most orchestral players prefer
  • OO (Very Open): Huge backbore for enormous, rich sound (takes a lot of air)

Specialized backbores

We also have some specialized backbores that are different than the "standard" line:

  • AOS: Designed for C trumpet players looking for a large and warm sound, it's open and free-blowing. It provides a feel and sound spread that is perfect for orchestral playing and for chamber music.
  • KA1, KA2, and KA3: Based on the great customer response to our A2 backbore we decided to expand our commercial backbore line with the three new options in our KA Series!
  • VNT: a vintage trumpet shank backbore specially designed to work with pre-1930's classic trumpet shanks (King liberties, Holton Revelation, Martin Handcrafts, etc), available here.

Cornet Backbores

We also have two different cornet backbores available (one in standard length, and one in the short "British" length which works nicely with larger tops). 

Flugelhorn Backbores

Choose between our Large and Small taper flugelhorn backbores, available in our standard weight only.


All trumpet mouthpiece backbores can be ordered now to be cut for sleeves in the drop-down menu (the sleeves are not included in the purchase; backbores cut for sleeves will not work without the sleeves). 


Special Order Options Call (816) 410-0826

Throat sizing: All backbores will be made with a #27 (.144) throat. If you would like to change it to a custom size we can do almost any modern size. Let us know we'd be happy to help!

Gold plate: Gold plated backbores may be ordered over the phone. Gold plating will add $30 and an additional 3-4 weeks for delivery.

Threaded backbores for Adams integrated receivers: We can make backbores for the Adams A8 integrated mouthpiece receivers (requires a specialized mouthpiece top as well).


If you have additional questions send us an email

Prior to ordering please check our Shipping and Returns policy.

Also note weight indicated in the ad is shipping weight not actual weight of the item.

We have mouthpieces equivalent to the Laskey 84D, Warbuton 2D, Laskey 84B, Warbuton 2MD, Laskey 84C, Warbuton 2MC, Hickman GW, Bach 1X, Monette B1-1, 30's Bach NY1, Vincent Bach 1 mouthpiece, Laskey 80B, Haefer, Yamaha 16C4, Schilke 16C4, Bach Mount Vernon 1 1/4C, Curry 1.25BC, Bach 1 1/4C, Bach 1/4 C, Tilz 1 1/4CE, Monette B2, Monette B2S3, ACB 1.25C, MV 1-1/4C, Monette B2LD, Tilze 1 1/2E, Bach 1 1/2B, Monette B3, Curry 1.5BC, Warbuton 3MD, Bach 1.5C, Monette B3, Curry 1.5C, Warbuton 3MC, Bach 1.5C, Monette B3, GR 67, Monette B3L, Bach 1.5D, Mount Vernon 3C, GR 66.5, Mount Vernon 3B, BH3, Monette B4, Bach Mt. Vernon 3, Monette B4S, Bach Mt. Vernon 3D, Monette B4L, Bach 2 1/2C, Bach 3D/E, Curry 3DE., Monette B5L, Bach 3, Bach 3B, Monette B5, Bach 3, Warbuton 4MC, Schilke 14B, Monette B6s1, GR 65M, Pickett 5D, Monette BLM, GR 65M/S, Monette BL, GR 65S, Pickett 5E, New York Bach 5B, Pickett 5B, GR 74.7 MX, Bach 5B, Pickett 5C, Curry 5C, Monette B6, Giardinelli 7M, Bach 7D, Monette B7, Bach 7E, GR 64S, Giardinelli 7S, New York Bach 7, New York Bach 7B, Giardinelli 10M, M Shew 2, New York Bach 10 1/2C, Shew Yamaha Lead, Marcinkiewicz Shew 1, Giardinelli 10S, Schilke 14a4a, Monette B4L, Bach MV 3D, Marcinkiewicz Shew 1.75, Vintage Gustat Heim trumpet mouthpiece, Al Cass 1-27, Cat Anderson trumpet mouthpiece

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18 Reviews

  • 5
    Great backbores

    Posted by J on 28th Sep 2018

    ACB rocks! MO and O backbores shipped the next day!

  • 5
    Review of backbores

    Posted by Murray Gordon on 16th Sep 2018

    Perfectly made and outstanding!

  • 5
    All you need is there (S backbore)

    Posted by Mark on 13th Sep 2018

    I am very happy with my purchase. It had all the qualities that I wanted in sound and ease of playing :)

  • 5
    Heavy Tight Backbore

    Posted by Harrison on 24th Aug 2018

    I wanted a heavier mouthpiece so more sound transferred into the horn and a lead mouthpiece because I play quite a bit in the upper register, Double A on a regular basis. This piece plays crisp, notes are well defines, and I cut through a 25 piece brass group that plays loud. It's a keeper!

  • 5

    Posted by Blaine on 2nd Dec 2017

    Fantastic quality and Trent provides a great description of each. I have the MO and S backbores that I pair with an MV3C and MV3L. I have an MT on the way as well. I like to experiment swapping them around for different sounds I like. I have used another brand of two piece system in the past and I prefer these backbores by far. Simple sub set of options to pick from depending on what you want, no guessing between a 3-4 like you have to with competing brands. I think this is huge when making an online purchase when you can’t test before buying.

  • 5

    Posted by Juha on 13th Jan 2017

    Slug backbore great all-round backbore for me.And works great acrylic tops

  • 5
    great backbore

    Posted by kevin s on 5th Jul 2016

    I had trouble with my old mouthpieces, partly because the backbores were so restrictive. Trent paired his new Gen II 3S top with the T backbore and I've got a winner,

  • 5
    best backbores around

    Posted by E Bone on 30th Jun 2016

    I've always had a hard time with backbores from other manufacturers. With ACB backbores, however, they just seem to work great for me. Perfect balance of resistance and color. Thanks Trent!

  • 5
    ACB mouthpiece system the best ever

    Posted by Bill Mirrielees on 25th Aug 2015

    Just got finally dialed in with the perfect mouthpiece combination of top, blank and backbore for my A4. Fabulous!

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