# Pom-pom guns - what's the purpose of the shape of the end of the barrels?

**URL:** <https://boards.straightdope.com/t/pom-pom-guns-whats-the-purpose-of-the-shape-of-the-end-of-the-barrels/730355>\
**Category:** Factual Questions\
**Created:** [September 8, 2015, 5:59pm UTC](https://boards.straightdope.com/t/pom-pom-guns-whats-the-purpose-of-the-shape-of-the-end-of-the-barrels/730355 "2015-09-08T17:59:59Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\
**Post date:** [September 8, 2015, 5:59pm UTC](https://boards.straightdope.com/t/pom-pom-guns-whats-the-purpose-of-the-shape-of-the-end-of-the-barrels/730355/1 "2015-09-08T17:59:59Z")

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I still remember the first time I became aware of [pom-pom guns](https://en.wikipedia.org/wiki/QF_2-pounder_naval_gun). My father had come back from a business trip and brought with him a set of toy pom-pom guns. I was thrilled by it - there was something about the name ‘pom-pom’ that struck a chord, and I also loved the sound it made (pom pom pom pom pom . . . duh ;)). But it was their unique shape that really enthralled me.

To this day I still don’t know why pom-pom guns have the shape they do. I am referring, of course, to the business end of the pom-pon’s barrel and its iconic cone-shape. [Here is a nice picture of them](https://en.wikipedia.org/wiki/QF_2-pounder_naval_gun#/media/File:MkVIIIpompomsHMSRodney1940.jpg) from the Wikipedia article linked to above. And [here’s another](http://www.maritimequest.com/warship_directory/great_britain/photos/aircraft_carriers/illustrious_87/1941_00_00_pom_pom.jpg).

Is the purpose of the cone shape to act as a muzzle brake? Flash suppressor? Since they’re not held or fired by a person, it wouldn’t seem that a muzzle brake or flash suppressor would even be needed. So, why are they shaped that way?

Thanks!

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**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\
**Post date:** [September 8, 2015, 6:18pm UTC](https://boards.straightdope.com/t/pom-pom-guns-whats-the-purpose-of-the-shape-of-the-end-of-the-barrels/730355/2 "2015-09-08T18:18:52Z")

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If you follow your first link to the page on the Bofors gun, you find this quote:

> [@](#):
>
> In spite of sharing almost nothing with the original design other than the calibre and the distinctive conical flash hider […]

So, it’s a flash hider.

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**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\
**Post date:** [September 8, 2015, 7:28pm UTC](https://boards.straightdope.com/t/pom-pom-guns-whats-the-purpose-of-the-shape-of-the-end-of-the-barrels/730355/3 "2015-09-08T19:28:05Z")

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Necessary because the barrels are so short.

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**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\
**Post date:** [September 8, 2015, 9:51pm UTC](https://boards.straightdope.com/t/pom-pom-guns-whats-the-purpose-of-the-shape-of-the-end-of-the-barrels/730355/4 "2015-09-08T21:51:50Z")

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Thanks for the answers.

Just to be clear, then, the flash hider is required to protect who/what in a system like that? The loaders? And from what? ‘Back-blast’?

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**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\
**Post date:** [September 8, 2015, 10:00pm UTC](https://boards.straightdope.com/t/pom-pom-guns-whats-the-purpose-of-the-shape-of-the-end-of-the-barrels/730355/5 "2015-09-08T22:00:05Z")

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Loaders and gunners. Short barrels = incomplete combustion of propellant = lots of “back-blast.” Not so much “flash hiders” as “flash shields.”

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**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\
**Post date:** [September 8, 2015, 10:20pm UTC](https://boards.straightdope.com/t/pom-pom-guns-whats-the-purpose-of-the-shape-of-the-end-of-the-barrels/730355/6 "2015-09-08T22:20:16Z")

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> [@silenus](#):
>
> Not so much “flash hiders” as “flash shields.”

I would imagine that under low light conditions, not being blinded buy the muzzle flash would be critical.