Bulging Barrel w/Rust Preventative

Hello All,

I was conversing with a fellow the other day, and he asked about leaving the ML's loaded, perhaps for a week between weekend hunts. (He doesn't shoot ML's by the way.) I mentioned some of us will leave the rifles loaded, and some people that I know will run a patch with Barricade or something down the barrel, and not leave the rifle upended, but will store it horizontal.

He expressed concern that if one did not remove the rust preventative and then fired the rifle that the projectile might cause the oil (or rust preventative) to accumulate on the projectile as it moves down the bore. Then if the bullet overtook this deposit, it could cause a bulge as it compresses the oil against the bore. He had made such a mistake, though it was almost not noticeable, it had ruined his barrel for accuracy in his breechloader.

I explained that I thought a ML projectile fired by black powder wasn't going fast enough (compared to his modern cartridge which caused the problem) but velocity aside, I told him the cloth patch would fail from compression of the oil before the bullet would cause problems with the oil against the barrel, in my case. Folks shooting conical bullets, the back end is forced onto the rifling, and the soft lead would be force off the rifling before the steel would be harmed from compression, and even somebody shooting a sabot the plastic of the sabot would fail before the compression would harm the steel.

I pointed out in his case it's a jacketed bullet with the jacket being forced onto the rifling lands and probably with about 1000 fps more muzzle velocity in his case vs. "us". But mine was a supposition, not real knowledge.

Anybody every heard of bulging a barrel with a muzzleloader from oil left in the bore???

LD

Anybody every heard of bulging a barrel with a muzzleloader from oil left in the bore???

Click to expand...

Nope....
I don't think it's possible unless you're using cosmoline as a rust preventative... :shocked2:

Just think of all the once a year dear hunters that grab their gun and go...there should be millions of ringed barrels out there and there aren't.

Also, you can fire a gun under water without ringing the barrel....

I'm not concerned with "possibility"...give me "probability"
I have to question how he knows it was the rust preventative and not something else?

Regarding storage, I store mine muzzle up...that way any accumulation is against the ball and absorbed by the patch. muzzle down and it accumulates at the muzzle where the barrel is most vulnerable.
But ringing is usually done close to the chamber and is the result of over pressure....
was this guy a hand loader?

So, the last thing to mention is that in a muzzleloader when I leave it loaded, I use patch lube (beeswax/olive oil which doesn't run)as a rust preventive or I wipe the excess out if using something from a spray can.

Bottom line....if he ringed a barrel it was due to error...not a rust preventative.

Sounds like someone trying to rationalize a screw-up to me....

I don't know if it is true or not but I have read that bulged barrels, caused by an obstruction towards the muzzle are caused by the concentration of the pressure wave created by the exploding/burning powder charge.

When the powder ignites it creates a massive amount of pressure and the pressure wave formed travels up the bore at a sonic or supersonic velocity.

If it hits a obstruction like a stuck bullet or even a snow or mud plugged muzzle, the energy is transferred to the barrel.
The concentrated energy then expands the barrel greatly at that location. If the expansion exceeds the strength of the steel, a ring will be formed.

With a layer of oil in the bore like the original post described, as the projectile travels up the bore towards the muzzle it would wipe off the oil, accumulating it just in front of itself. This would essentially add the mass of the oil to the weight (mass) of the projectile.

This would be a uniform increase in the mass. It would not be a sudden thing so it would not concentrate the force of the explosion into the wall of the barrel at any location so although some velocity loss will happen, there should not be any damage to the barrel.

If the OP's friend damaged his barrel, I think something other than a oily bore was going on.

Possibly, he loaded an oversize FMJ bullet into his gun and fired it?
(Ya, I know. We don't talk of such things here but that's the only thing that makes sense to me.)