7.62mm ASHOT rifle - Part 4: Rifled barrel

Previous Chapter - Part 3: Chamber

 

Once the breech and chamber passed the fool proof test, I move on to make the long barrel

A hydraulic tube, some of it turned down to 12mm (you can do whatever length you want), this act as chamber interface.

Metal surface was grinded off to give the weld a better bind.

 

My welding was shit, I know. But it works.

 

As mentioned in Part 1, welding cause metal to warp/shrink. After welding the 20/16mm sleeve will no longer be able to slide onto the barrel

 

To mitigate this I first cut the sleeve in half. Then secure them with metal wire or hose clamp before welding to 14/10 OD/ID tubes

 

 

Hose clamp will keep them together, secure the barrel from flying out the front

 

The whole system when assembled, with a round loaded in the chamber.

Are we missing something?

Ah yes, the rifling. Can't shoot straight without that.

I came up with a jig to push button rifling some times ago. Unfortunately the barrel must be put at an angle to put into that. This barrel is too long to for that to work. So I went cave men mode. Using a hammer I pushed the button through after about half an hour. 

 

 

 

Test fire the newly made barrel

59mm thick block of wood is the target, then a back stop placed behind to capture the escaping projectile (this thing has alot of energy)

 

 

Not sure where the sparks came from. Maybe it's steel on steel impact (there are some steel projectile remain within the block of wood from earlier tests)

 

Projectile entrance 

 

Projectile exit. Make a gnarly scene

It went through 59mm of wood, then move on into the back stop. Because the projectile has steel core, it penetrate everything in its path and still want to keep moving. 

 

Recovered projectile show interesting deformation 

 

In an attempt to fire a sub-sonic round, the reduced powder load was insufficient to send the projectile all the way down the bore, lead to a squib load. Not a great experience, but sure left a good souvenir 💁

 

 

Next chapter - Part 5: Assemble and Firing