What Causes This?...

[BCB]

This case is a 30-30 that has been turned into a 7-30 Waters...

It has been fired at least a half-dozen times from a T/C Contender...

The load was 32.5 grains of H-335 and the Hornady 120 V-Max bullet, no not a cast boolit, and I have been shooting this combo for a good many years. The bullet originally was the Hornady SSPSP but then became the V-Max--fancy tips sell to those who sometimes seek "chrome" on Harley's!!!

Anyhow, I wonder what caused this. I have never seen this with my own personal reloads in the entire time I have been reloading...

Thanks...BCB

[sturf]

Appears to be a lube dent. Caused by using too much case lube durring sizing and or not cleaning it off. It builds up causing a dent. Should not hurt to fire the case.

[ReloaderFred]

If it occurred during the sizing process, then it was caused by excess lube, but if it was caused when the round was fired, it was caused by the neck not sealing the chamber fully and pressure blew past the neck and dented the case.

Hope this helps.

Fred

[BCB]

Appears to be a lube dent. Caused by using too much case lube durring sizing and or not cleaning it off. It builds up causing a dent. Should not hurt to fire the case.

I know this happens during sizing when too much lube is on the case...

BUT this is what the case looked like AFTER it was fired...

Is that still what you meant by having too much lube on the case?

I clean all of my cases after sizing in a water solution containing GoJo hand cleaner. There is no lube left on the case when it is loaded...

Thanks...BCB

[44man]

Pressure got where it didn't belong.

[gon2shoot]

Yup, had blow-by.

[high standard 40]

I agree with the blow-by explanation. I saw one just like that at the range just 2 weeks ago. The shoulder-neck area did not seal and pressure migrated back between the outside of the case wall and the chamber, denting the case.

[Changeling]

It does look like pressure during firing, but no smoke/powder marks, and it appears a rectangular tool approximately 3/16" long slightly flat bottomed (like a screwdriver blade), of some kind was used to indent the case. Pressure doesn't leave that type of "defined" rectangular mark, just a dent. I think you are playing a joke on us, LOL!

[MakeMineA10mm]

It does look like pressure during firing, but no smoke/powder marks, and it appears a rectangular tool approximately 3/16" long slightly flat bottomed (like a screwdriver blade), of some kind was used to indent the case. Pressure doesn't leave that type of "defined" rectangular mark, just a dent. I think you are playing a joke on us, LOL!

I noticed the lack of scorch marks too.

My thought is the case hit something on the ground when ejected/dropped and was then stepped on, creating the odd dent. Of course the high state of polish might explain it too... Perhaps this case was polished after firing, removing the scorch marks?

[Changeling]

If your scenario was correct to cause that much of a peculiar dent it would also have been enough to flatten somewhat the forward part of the case, just my opinion.

[BCB]

Now you guys got me wondering myself…

I figured it was pressure leaking past the neck if it didn’t seal properly and there may have been a bit of blackening on the case, but I did wipe it off, but only with my fingers. I really don’t remember any noticeable amount of soot…

Nope Changeling, I ain’t trying to play a joke…

But as I look at it also, it almost does look “perfect” in its shape. But if you (in the plural sense) look closely at the dent, it does start at the bottom of the shoulder, right at the junction of the shoulder and the body. This still might indicate a pressure escape area…

I wonder if there could have been a speck of powder or even a grain of sand from a sandbag that was right at the junction…

Now then, my Uncle did open the action on the T/C Contender and I suppose it could have been partial closed on the fired case, somehow, before it was removed. Although, there are no scratch marks where steel would have come in contact with the brass. And dropping it to the floor would not have caused such a dent. I was standing about 10 feet away so I would have probably noticed if the dent was put there post-firing…

We did fire a dozen or so rounds after that one and there was not one problem—not a blemish on any case. All came out almost as clean as when they entered the chamber. As a matter of fact, every round connected with a 12-ounce beverage can at 100 yards. (That Waters is a shootin’ rascal—both cast and J-word boolits/bullets!)…

It is still a mystery to me…

I am interested in other shooters thoughts. Even after 40+ years, one can learn something or be completely puzzled by something…

Thanks and keep ‘em coming…BCB

[44man]

Chalk it up to a one time event, nothing to really worry about unless every case does it. A bullet that moved before good ignition or how the primer lit the powder. Too many things can do something like that.

[Trifocals]

I tend to lean toward the case neck not expanding and sealing when the round was fired. Have you had any neck splits? Have you annealed your brass? It could be the necks are getting work hardened and brittle. Just my 2 cents worth. LOL

[BCB]

Yea, I'm not worried at all. Actually the case show zero indication of any type of failure. The primer looks extremely "normal" The dimple is the same as the other ones...

The brass was originally annealed to allow fireforming to occur a bit easier, but that was the last time. I agree that the brass could be getting a bit hard or brittle as it has been fired a good many times, yet I have some brass that I use in this Waters that has been fired over a dozen times...

Yet, it is intersting as I simply have NEVER seen this with any of the, gawd only knows how many, of the rounds I have reloaded and fired...

Think I will add it to my "neat" stuff collection of the past years...

BCB

[Guesser]

I had that happen many years ago in a 30-30 Contender. I was loading plinking loads using the Speer 100 gr. Half Jackets. Happened a couple times, never gave it a thought at the time. I've seen and heard it mentioned several times over the years since. Contenders and bottle neck cases are the only combinations I've heard about this happening to.

[buck1]

I have never seen that happen. A lube dent would have blown out, If pressure leaked by , there would be pressure still in the case and it should not dent. I would think anyway.
But I know that in air guns oil when subjected to heat and pressure can ignight the oil and cumbust like a diesel engine. Now You had the pressure and with a touch of super heated blow by and a smidge of oil... POP!...A dent just after the pressure drops in the case.
Its no more than a guess but it sounds good anyway! and is the only thing I can think of. LOL!

[white eagle]

Lube !

[NSP64]

Lube !

I agree. maybe not case lube. could be oil from uncles finger or some other source.

[Dan Cash]

I believe that it is a blowby problem caused by an imperfect mating of powder type and charge weight with projectile. Years ago I used a .30-30 contender for handgun silhouette. The bullet was a Loverin type bullet and I think the powder was Reloader 7. Until the charge weight was upped to something over 20 grains, at least half the cases showed soot and dents.