Barrel issue ?? Strange

[shooters]

Admins please move if not in right place. Wasn't sure where to post.

Factory Savage 110 6 Creedmore.
Thunderbeast Supressor
Factory Hornady 108 ELDM
260 rounds down tube.

To get this out of the way. Barrel has been cleaned and Recleaned, and the cleaned again.
Bortech Carbon cleaner over and over. Let sit multiple times for 40 min. Honestly frustrated to the point that I didn't care if I ruined the barrel I cleaned so much. I scrubbed and scrubbed even with Montana Xtreme Cream.
Ran Montana Xtreme Copper killer through it until no blue. Then went back to look for Carbon and after heavy scrubbing and sitting, no black even came out first patch. No tight spots in the barrel.
Ive cleaned the barrel after about every 40-50 rounds so it's been cleaned multiple times.

So, two things. Other day I shot steel 10-20 times on about a 20 min span. About the 8th shot, I heard a different sound than the normal firing. Back of brass dented out and primer blew out. Lots of pressure. This is with factory ammo. Only happened once out of 260 rounds. I assumed and still assume it was from a Carbon Ring build up.
So WHY the carbon ring build up? I treat the gun same as every 243 up to 300 Ultra I have. Never once had an issue. Other reason I assumed it was a carbon ring is because of the following pictures.

Now I'm sure there are gonna be lots of "that looks like ammonia build up or cleaner left behind in the barrel" but I can assure you it's not. The gun would do this before I even cleaned it the first time new from factory, I've ran a borescope down it and too my best, there's no copper or carbon and NO cleaner. Even had a gunsmith friend tell me to shoot carb cleaner down it so that was done multiple times and then bore conditioner patch followed by a dry patch.
So heres the problem. And safety was followed when leaving round in chamber so keep the comments out.

1st pic bullet left to right is if round is left in throat about an hour. Middle bullet is about 2 hours. Far right is about 4-5 hours.
2nd pic (green/blue bullet) is of bullet is left in overnight.
I do live in Cold climate and first assumed it was from condensation forming in barrel from hunting in cold temps, then bringing gun into warm house and with bullet out, it gathering water overnight and then next day bullet goes in and sits in there. I made sure this didn't happen. Ran patch through it before going back out.
I really have no clue what's going on but sure lots have an answer or experienced it. Someone mentioned the carbon ring is caused by the supressor creating extra back pressure and gasses not escaping and building up that carbon ring but for the life of me I don't think it has a carbon ring issue. Thanks!

 

[lancetkenyon]

Dissimilar metal corrosion.

 

[Jud96]

Remove the suppressor, clean the barrel, and retest without the suppressor.

 

[shooters]

Dissimilar metal corrosion.

I was wondering if that was a possibility...but wouldn't there be some major issues with thousands of savages and or Hornady bullets?

 

[shooters]

Remove the suppressor, clean the barrel, and retest without the suppressor.

Just finished cleaning it and will fire shoot 20-30 in the next week or so at some steel and see what happens. Thanks!

 

[lancetkenyon]

Maybe don't clean it as much. Seriously. I have rifles that go 250+ rounds between cleaning. Get some carbon in there and see what it does.
Also, have you checked to see if you are touching the lands? If you had one overpressure, could it have been seated out further and jammed hard? That definitely increases pressure.

 

[Skimbleshanks]

That sure looks like copper solvent got on your bullets. With as much as you've cleaned that barrel its what id put my money on.

 

[Skimbleshanks]

This is a round that I had chamberd in my rifle on a particularly wet day that I didn't shoot an elk. I didn't tape my barrel either. Kept it muzzle down as much as possible but some water still got in there. I dont leave solvent in my barrel but im sure an absolutely tiny amount stays in there unless you are flushing at the end with acetone or alchohol.

 

[shooters]

Maybe don't clean it as much. Seriously. I have rifles that go 250+ rounds between cleaning. Get some carbon in there and see what it does.
Also, have you checked to see if you are touching the lands? If you had one overpressure, could it have been seated out further and jammed hard? That definitely increases pressure.

It did it before it was ever cleaned the first time. It's also factory ammo so I wouldn't think it's in the lands.

 

[shooters]

That sure looks like copper solvent got on your bullets. With as much as you've cleaned that barrel its what id put my money on.

The bullets we're doing this prior to ever being cleaned. I knew the the question of solvents would be brought up, but I can assure there is zero solvents or cleaners left behind. Gun smith ran bore scope down twice after being cleaned one, shot multiple times and then scoped again without cleaning. Just strange

 

[kiwikid]

Just finished cleaning it and will fire shoot 20-30 in the next week or so at some steel and see what happens. Thanks!

Shooters, when you left the rounds pictured in your chamber did you have your suppressor on and was the rifle left standing upright?

Here in NZ we have been using suppressors for many years and it has been found that the residue left in a suppressor after it has been used attracts moisture. This is worsened when the suppressor gets warm due to shooting and then is stored in a cold place. The moisture eventually runs down the rifles bore and can do severe damage to the rifling. I have personally seen several 22 LR rifles with corroded barrels due to the owners not removing the suppressor before storing their rifle.

 

[shooters]

Shooters, when you left the rounds pictured in your chamber did you have your suppressor on and was the rifle left standing upright?

Here in NZ we have been using suppressors for many years and it has been found that the residue left in a suppressor after it has been used attracts moisture. This is worsened when the suppressor gets warm due to shooting and then is stored in a cold place. The moisture eventually runs down the rifles bore and can do severe damage to the rifling. I have personally seen several 22 LR rifles with corroded barrels due to the owners not removing the suppressor before storing their rifle.

Really! And yes, the suppressor stays on BUT the rifle stays somewhat level just standing on the bipod, which I guess is enough of a slope to possibly cause moisture to run down the barrel.
Gun would be out all day in 10-15 degree temps and then come into 70 degree shop. Thanks for the response

 

[Gar Guru]

I have a 22lr with suppressor and if I take it off and put it back on poi shifts enough to adversely affect squirrel hunting. I take mine off twice a year and clean whether needs it or not, and it is usually fairly dirty. I will just have to take a chance on corrosion as that is less painful than listening to my son whine about poor accuracy and resighting frequently.

 

[kiwikid]

Really! And yes, the suppressor stays on BUT the rifle stays somewhat level just standing on the bipod, which I guess is enough of a slope to possibly cause moisture to run down the barrel.
Gun would be out all day in 10-15 degree temps and then come into 70 degree shop. Thanks for the response

One easy way to see if this is the issue is shoot a few rounds with your suppressor on and when you get home take the suppressor off and sit it upright on a paper tissue where you normally store your rifle. The next day have a look at the tissue.