When does a smoothbore shotgun barrel "shoot out"?

[jkpq45]

Hello All,

I understand wear on rifling in rifled barrels--high velocity, hard bullets and high temperatures cause erosion to the rifling, throat/leade and muzzle crown.

If I'm dealing with a chokeless smooth-bore shotgun barrel, shooting slugs through a 5 degree throat/leade, what will wear on the barrel look like? Do they "shoot out" like rifle barrels or do the groups eventually open up?

Thanks,
jkpq45

 

[drsfmd]

Shotgun barrels don't wear out. Ever. Unless they have been monkeyed with.

I know of one that "wore out". It was a trapshooter who had his barrel bent to make it shoot higher-- you guessed it, over time, he wore right through the bottom of the barrel.

 

[jkpq45]

I'm assembling a 12 GA From Hell project per Mr. Ed Hubel's experimentation. Expecting 6,000+ ftlb slug loads from this barrel; though in sabots. Perhaps that qualifies as "monkeying with" the barrel?

Can't believe he did that to the barrel. I think I'd recommend a tapered rib (shorter at the front than at the back) and/or an elevated comb.

 

[drsfmd]

I'm assembling a 12 GA From Hell project per Mr. Ed Hubel's experimentation. Expecting 6,000+ ftlb slug loads from this barrel; though in sabots. Perhaps that qualifies as "monkeying with" the barrel?

Can't believe he did that to the barrel. I think I'd recommend a tapered rib (shorter at the front than at the back) and/or an elevated comb.

Barrel bending was a fairly common practice years ago.

Given your intended use, I have no real opinion to offer-- what you are doing is way outside of what the barrel is designed for

 

[jkpq45]

That's the thing--I'm still shopping for the barrel stock. I have a 1.150" OD 12 gauge "heavy barrel blank" that will be sufficient to practice on, but I'll need a longer tube to get the higher velocities I'm looking for.

Just trying to plan for how many rounds I can throw down the tube before scrapping it.

 

[JohnBT]

"Barrel bending was a fairly common practice years ago. "

I saw a cable show on Beretta not too long ago that showed an experienced factory worker bending barrels by hand - eyeballing them too.

John

P.S. - There are 3 pics halfway down this thread, although I didn't see where it is.

www.duckhuntingchat.com/forum/viewtopic.php?f=13&t=173259

 

[dfariswheel]

What wears a gun barrel out is erosion in the throat just in front of the chamber.
This is in rifles, and is due to the effect of abrasive, super heated burning powder and plasma gas.
The heat and abrasive powder particles erode the metal.

Shotguns operate at much lower pressures and erosion is not the problem as in rifled barrels.
In addition, in shotguns you have plastic wads or sabots further protecting the barrel.
Shooting sabots in a smooth bore barrel would likely not wear the barrel much at all, and I'd expect barrel life to be virtually unlimited.

 

[drsfmd]

John-

That's different. They are truing the tubes. This was a finished gun where he had the barrel bent upwards a few degrees to make the gun shoot higher.

 

[1SOW]

Back in the late 60's, Holding up a new 30" Win 870 "TRAP GUN" and looking 'through' the bbl, the chamber and bbl ends are not concentric. The two I looked at showed a slightly "upward bend" to the bbl. The gentlemen trying to teach me trap shooting pointed this out to me. The guns came this way NIB.

With no slugs or steel, they'll shoot forever with normal care.

 

[Promod1385]

Barrel bending to adjust POI is very common. There are some top gunsmiths out there who have a favorite telephone pole or wooden post to "adjust" barrels on.

Benny Hill is one who comes to mind who uses this technique.

 

[BADUNAME30]

Young trees with a V in 'em work great.

 

[JohnBT]

"That's different. They are truing the tubes."

It's not much different though, is it? Some barrels are bent before the gun is assembled and some are bent after the buyer takes possession.

"Barrel bending to adjust POI is very common."

Although a rib can complicate things.

John