Rifle condition

[Tb54]

Was cleaning my rifle today and probly because of something I read on this site, I noticed a spot in my bbl, about 8” from the breech end, where my jag with patch on it slipped about an inch. Tried it a couple times, with a couple different patches (2x2, 30 cal cotton patches). Each time in the same spot the jag slid easily suggesting a bulge in the bore. I did not pick up a bulge when I calipered the outside.

That mean I need a new bbl?

 

[Robby]

You probably 'rung the barrel'. If the ball isn't seated all the way down on the powder, upon ignition the gas expands and is compressed at the ball creating what might better be described as a dent around the bore, as opposed to a bulge which is detectable on the outside as well. There are varying opinions about it with respect to safety, and I don't know the truth of it so I'll stay away from that discussion.
Robin

 

[Britsmoothy]

Don't worry about it as long as it shoots straight don't worry about it.
I have read a few accounts of ringed bores actually shooting better than before. Don't ask me where the info is as it was in old rifleman magazines years ago.
I did ring a Remington 527 once and it shot better than before.

If you don't want the gun and want it disposing of safely send it to me.

B.

 

[Tb54]

Ok, I’ll try it. Remember reading something once about a bbl won’t shoot straight once something like that happens to it, so I didn’t know if I would just be wasting time trying or not. For all I know it was that way before I bought it used 25 years ago... but then it never was real great accurate. It never occurred to me before to find its load either.

 

[Tb54]

Silly me. It was Dutches book I read it in that accuracy from a bulged bbl wasn’t likely. Read it again tonight. He described my situation too, the jag falls about an inch, even though no bulge is evident on the outside.

I understand why that would happen, but the physics I don’t since the entire volume of the bore behind the ball, would be subjected to the same psi, yet only an inch behind the ball rings?

 

[Britsmoothy]

Eventually the ball moves and excessive pressure drops.
Don't condemn the barrel until you have tested it. And don't go off negative opinions.
Every test I read about confirmed nothing bad happened to accuracy!

 

[Loyalist Dave]

Well the options are:
[ ] Try conicals in the barrel if round ball fails, as the momentary loss of friction might not effect the conical as it would the patch on a round ball.
[ ] Have the barrel reamed and perhaps re-rifled by Bob Hoyt
[ ] Replace the barrel

Good luck to ya!

LD

 

[Grenadier1758]

What you have is in effect a jug choked barrel. In this case the jug was done accidentally near the breech. If minimal harm was done to the barrel and there may be no adverse effect. The rung portion of the barrel will allow the ball to expand (obdurate) slightly and then be forced back into the bore. This is similar to the forcing cone on a revolver. Shoot with mild loads and look for changes in accuracy.

I would always check to see if the rung out section of barrel changing. If the loose section gets bigger or a bulge is noticeable on the barrel, then the rifle is a wall hangar or the barrel should be sent off to be relined.

 

[Tb54]

Thanks. I’ll test it.

Calipers don’t reveal any bulging.

 

[Tb54]

Calipers didn’t reveal bulging, but I borrowed a mic from a guy at work and found a .005” bulge at the point the patched jag slips in the bore.

 

[Britsmoothy]

Calipers didn’t reveal bulging, but I borrowed a mic from a guy at work and found a .005” bulge at the point the patched jag slips in the bore.

I thought there must be some external evidence.
That's nothing!

 

[azmntman]

Like Greandier stated, you have a jug choked barrel. Heck....it tightens patterns right up in a shot gun! Let us know how it works.

 

[Tb54]

I will, and thanks for the confidence. I’m looking forward to my next shooting session.

 

[M. De Land]

Was cleaning my rifle today and probly because of something I read on this site, I noticed a spot in my bbl, about 8” from the breech end, where my jag with patch on it slipped about an inch. Tried it a couple times, with a couple different patches (2x2, 30 cal cotton patches). Each time in the same spot the jag slid easily suggesting a bulge in the bore. I did not pick up a bulge when I calipered the outside.

That mean I need a new bbl?

I ringed a .50 cal Thompson Center once shooting conical bullets. It slipped forward one day while moose hunting and on the way back I shot a spruce hen with the slug and ringed the barrel about 8 inches back from the muzzle. I detected it when I went to the range again and couldn't keep the ball on paper at 100 yards. The gun previously would stack balls at 50 yards but no more.
When I felt it while cleaning I could hold the barrel up to good light and see the bulge while looking down the outside at a shallow angle.
The other thing to consider is that the barrel wall has been stressed at that point and most certainly is weakened from it's original strength. I'd get a new barrel and be safe. I did and went from a .50 cal to a .54 cal which I am very glad about for hunting and target shooting.

 

[RedFeather]

I've heard of this in Trapdoors shooting light loads in the big case. Usually rings the chamber. Best explanation I've seen is that the flash goes over the loose powder igniting it sooner. This will create a pressure wave which bounces off the base of the bullet, meeting a wave coming forward from the powder at the base or breech. When the two meet, they form a pressure spike. Kind of like sloshing around in the bath and creating one big wave.

 

[Britsmoothy]

I've heard of this in Trapdoors shooting light loads in the big case. Usually rings the chamber. Best explanation I've seen is that the flash goes over the loose powder igniting it sooner. This will create a pressure wave which bounces off the base of the bullet, meeting a wave coming forward from the powder at the base or breech. When the two meet, they form a pressure spike. Kind of like sloshing around in the bath and creating one big wave.

Yep, rule#1, no cavities. Advised for smokeless too in my book!

 

[BrownBear]

I've heard of this in Trapdoors shooting light loads in the big case. Usually rings the chamber.

Yup. Good comparison. I could go off down that cartridge tangent, but won't. In a nutshell, it's just like not seating a ball or conical down against the powder in a muzzleloader.

I'd have zero concerns about a .005" ring 8" from the breech. It's shooting good, and that's all you need to know.

 

[hanshi]

I once experienced a loose spot (rung barrel) in a rifle. But it was still one of the most accurate .50s I ever fired. While it didn't affect accuracy, I still knew it was there and I didn't like it.