Marlin 981T has rings inside barrel

[leathermanwave]

My brother's .22, a Marlin 981T, has two rings inside the barrel. By rings I mean that when looking down the barrel there is a section about 1/4 inch long that has no rifling, they both can be felt when cleaning the barrel it feels like a small spot that is looser than the rest of the barrel.
A while ago the gun was on a window mount of my brothers truck and I have a feeling that the heat may have caused the rings, one of the rings has been there for about a year and it was taken out of the truck, now a second ring has appeared recently.
The gun is still a very accurate .22, but about every 100 rounds a shot will sound strange and the bullet will be way off target.
Any Ideas of how the rings got there and if they are important?

 

[ThomasT]

Have you been shooting any Aquila Colibri or Super Colibri ammo through it? How about really old ammo that wasn't properly stored?

 

[briansmithwins]

Shooting stuck bullets out of a .22 will do that.

BSW

 

[Uncle Mike]

You say there are two spots inside of your barrel that have no rifling...? About 1/4" long and encompasses the entire inner circumference of the bore...?

 

[Runningman]

Wasn't the heat from the window mount.

I've seen more than a few 22s over the years with ringed bores some with more than one and one that had six rings in the bore. The one with the six rings was owned by a friend who would store 22 ammo in his truck year around and was always having problems with his 22 ammo. Just looked at a old 1 generation Colt SA 45 a couple weeks ago that had two rings in the bore.

It is normally caused when you fire a bullet behind a bullet that did not make it out the bore (squib load). Firing bad ammo, improperly stored ammo, or to low of velocity ammo out of it can cause a bullet to stick in the bore.

 

[MikeJackmin]

Guns with ringed barrels - especially .22s - will often shoot quite well, despite the damage. If the rifle is still accurate, it's still good...

 

[leathermanwave]

You say there are two spots inside of your barrel that have no rifling...? About 1/4" long and encompasses the entire inner circumference of the bore...?

Exactly that

Have you been shooting any Aquila Colibri or Super Colibri ammo through it?

Once when there was one ring, but there was still only one ring after finished shooting colibris through it.

How about really old ammo that wasn't properly stored?

Yes, that may be it

If the rifle is still accurate, it's still good...

As long as it won't blow up.