Austin Custom Brass Backbores

Austin Custom Brass
"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
(27 reviews)
1.00 LBS
5.00 (in)
5.00 (in)
5.00 (in)
Current Stock:
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Austin Custom Brass Backbores

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).



Backbores that need to be built will have a 4-15 week lead time. 

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


  • 5
    AOS backbore

    Posted by David on 22nd May 2024

    Bravo!! You've done it again. Having found the best mouthpiece yet for my Bb (and general all around playing) I thought I would try the same top with your AOS backbone (made especially for C Trumpet). I could immediately hear the difference. The sound locked in even more solidly and the overtones really popped. Now my C, which is the best blowing C I've ever encountered just got better yet. I'm sold. The New Standard 2C (the "new" MV3C) coupled with this backbone is terrific. For me. I know every player is different but highly recommend you give this a try. It sure works for me. Yea!!

  • 5
    Machined to Perfection!

    Posted by Tony C. on 6th May 2024

    I've had repeatedly good results with the ACB series of backbores (I believe this is my 6th or 7th!). I've found them to be consistently machined to very exacting standards - a perfect fit for any #27 top.

  • 5
    Backbore (O)

    Posted by Mykhayl Chetverkin on 14th Dec 2023

    I ordered beckbore (O), and now I use it with a shallow cup. Very pleased, good quality and goes well with small tops, similar to Bach 117. Thanks to Josh and Trent for fast and efficient service and patience with capricious customers)))

  • 5
    KA3 backbore

    Posted by Jackson Harpe on 20th Mar 2023

    Discovered recently that I function best with a tighter setup, but not so tight that I feel like I'm hitting a wall with my volume. The KA3 backbore makes a lot of things so much easier and I can push it as much as I need to without fighting it. Great fit with my TA Lead mouthpiece top.

  • 5
    flugelhorn shank

    Posted by orwaikit on 4th Mar 2023

    smooth screwing with other brand mouthpiece top, ,the only choice of two pieces flugelhorn 6

  • 5

    Posted by Mike Forcina on 21st Feb 2023

    Great product

  • 5
    ACB Backbores

    Posted by Tony C. on 5th Dec 2022

    These backbores are machined to absolute perfection. Josh is an excellent representative and will get you set up with whatever you need for your individual playing setup. I bought 6 different backbores to cover me in any conceivable playing situation. You won’t find ACB-level customer service anywhere else, in my humble opinion.

  • 5
    Brass Backbores

    Posted by Gart Pollard on 4th Dec 2022

    Great product. Assistance from Laura was the best. If you’re looking for a new mouthpiece check these guys out and ask for Laura she knows her stuff!!

  • 5
    Great tone without sacrificing intonation

    Posted by Gordon on 14th Oct 2022

    I had been using an ACB MO backbore for piccolo trumpet for a while, and I was interested in what the O had to offer. My previous orchestral backbore, by another manufacturer, had great sound but went very sharp in the upper register. The ACB O backbore does a far better job of getting a good orchestral sound without going weird in the upper register. The other thing I noticed is that it gaps closer in my Bach trumpet, which is a set up aI prefer.