Austin Custom Brass Trumpet Backbores

Austin Custom Brass
$95.00 $78.00 (You save $17.00)
Weight 1.00 LBS
Height 5.00 (in)
Width 5.00 (in)
Depth 5.00 (in)
Shipping $3.00
weight Required
Thread for Sleeves (sleeves sold separately) Required

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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!


I've been working on a new design for the trumpet backbore line to make them as acoustically efficient as possible. Currently I have many different tapers available!

Standard 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.
  • AK: Another specialized C trumpet design, our AK backbore is a very large, symphonic backbore that is based on some of the best of Tottle designs. Used by orchestral players for decades (and very popular at one time in the BSO) the AK is an open backbore with a huge sound! 
  • KA1-3: 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.


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). 


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). 



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


For Gold plate add $30 and 3-4 weeks for delivery.


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

Product Reviews

Score: 5 out of 5 (based on 12 ratings)
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MTH backbore review
Written by Ron Jimison on 30th Apr 2020

I have a TA-3 top that did not match any of my (symphonic) backbores. I discussed with Josh what I thought I needed. He asked about my playing and my setup (Schilke B1-LB). He advised this MTH backbore. I will not know for the next month (or five?) when we can play gigs again how it works in a bi room, but here in my home studio it does just what I hoped. As always, the quality is perfect, and in spite of the current situation, shipping was very fast! Thanks to all at ACB!

Great Backbores!
Written by derek limback on 12th Nov 2019

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.

heavy backbores
Written by J on 8th Feb 2019

are fantastic! Love the response and the sound. Bought the S, O, MO, and MT and use them regularly!

Great backbores
Written by J on 28th Sep 2018

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

Review of backbores
Written by Murray Gordon on 16th Sep 2018

Perfectly made and outstanding!

All you need is there (S backbore)
Written 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 :)

Heavy Tight Backbore
Written 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!

Written 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.

Written by Juha on 13th Jan 2017

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

great backbore
Written 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,

best backbores around
Written 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!

ACB mouthpiece system the best ever
Written 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!