Gun barrel manufacturing

I don't believe the barrel had a square bore....just the ability to shoot square bullets, among other more conventional projectiles...the gun was unsuccessful in any case with only a few examples ever produced...however you can make a square hole from a round one with a tool called a broach...

https://www.youtube.com/watch?v=MYI1slVGziU&ab_channel=Clickspring

A replica Puckle gun is on show in the Bucklers Hard Museum, Hampshire, UK. The story goes that there were two versions. One, intended for use against Christian enemies, fired round bullets. The other, intended for fighting the Turks and other infidels, fired square bullets.

It's a moot point which one should be used in Ukraine.

Although there is a drawing of the chamber with square holes:-

I suspect that none were ever made, and, so there was no need to investigate the making of a square barrel.

Thanks for posting, that's a fascinating story.

I would think that square bullets would be more likely to jam in the barrel. Maybe the Turks would stand a better chance...

Being a blacksmith, I also enjoy a bit of history. Did you know that Abe Lincoln is the only U.S. president to hold a patent, and it was for making gun barrels? If you follow the way he did it , you basically make two troughed lengths of iron, then forge them to each other. It would most likely be easier to forge a couple of flat bottomed U shapes together than to forge a couple half circles together to form the tube (barrel). Besides that, barrels were formed by either making a helix shape around a mandrel and weld it together or by forming a tube and forge welding the seam together around a mandrel, for sure more work to perform that would hold up to an explosive charge.