Small bore rifle barrels.

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Klegenheimer

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I have often wondered just how a really small bore rifle barrel is made - bored and rifled such as as airgun or pellet gun? Is there anybody out there prepared to enlight me or advise where I could go to read up on it?
 

Ken I

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They are swaged down from tube (or gun drilled bar) using rotary hammer forging machines with a mandrel in the middle - after forming the mandrel is simply pulled out leaving the rifled bore.
The mandrel is only a short piece of rifling on an extension shaft as it only needs to be present at the "forging" portion of the process which progresses the length of the barrel.

Hammer forged barrels are also considered to be superior to broached barrels.

Regards - Ken
 
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MachineTom

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To expand on what Ken posted. A gun drillbit does not look like a drill, a long shaft with a straight flute or two to carry away the chips, a hollow bore to flow coolant to the cutting head, which is a carbide head with 1-2 cutting edges. I use a lathe for deep drilling,( Cannon barrels)so the tool is stationary and the barrel turns. A Gun Drill generally turns both barrel and tool
 
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I used to buy air gauge barrel blanks from Doug Shillen for my long range pistols. When I received them I cut them to length, chambered them and then crowned the muzzle. With a 10x power extended eye relief Lupold scope we were regularly returning 0.2" groups at 200 yards. Have got 7x Bisley Grand Master medals plus a lot of trophies but after our wonderful government banned all metallic cartridge hand guns I lost interest but have now come back to clay and black powder shooting.
 

a41capt

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Button rifling is a very common procedure these days, and is even doable in the home shop. Back in the 70s, I would hand forge a Black powder Muzzleloading barrel around a mandrel, hammer out a rough approximation of octagonal flats (to be ground and draw filed later), straighten and pull the mandrel, ream the bore, and then use a single tooth cutter on a pull type rifling machine. A VERY long and exhausting process, but for purists of the Muzzleloading sport, it produced a historically correct round ball barrel for my guns.

John W
 

Murph

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Had a chap ask how fast one can make a rifled barrel in a home machine shop. I walked over and picked up a 4" long piece of 7/16" DOM tubing that miked out at .310" ID, drove a 5/16"spiral reamer through it with a mallet, and handed it to him after driving it through. Job done in under 30 seconds. He really thought there was a lot more to it, told him there was, but he asked how fast, not how accurate or precise. The Polish resistance movement made barrels in underground factories much the same way, and with excellent results.

Polish rifling device.jpg
 

dnalot

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You can also buy rifled sleeves and glue or solder into a barrel. I tried that when I made my Gatling Gun, worked very well.


Mark T
 

Klegenheimer

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I have often wondered just how a really small bore rifle barrel is made - bored and rifled such as as airgun or pellet gun? Is there anybody out there prepared to enlight me or advise where I could go to read up on it?
Many thanks to each one of you for your most knowledgeable responses. I have been truly enlightened! In particular the video from Ken has well explained how commercial gun barrels are made. Mark's Gatling gun photos were a real bonus and also much appreciated. Hope one day to come close to your skill level.
 

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