Had my First case failure from pressure today - updated

[HuntClub]

No signs of pressure leading up to this event. None... no flat primers, no marks on bottom of case, no sticky bolt. Then, "Boom!" Well, it wasn't like that either. Made the shot. Ejected the round and thought "wow" when I saw the case. It was the third group with increased powder. Increasing in increments of 0.3 grains. First round of that group. Packed it up and headed home.... Just don't know what sign I missed before this happened.

Speeds were increasing as well as the other "no sign" issues listed... until this shot. Speed decreased. Case ruined. I threw the other 6 cases in the trash too... just being safe.

Any idea on what I missed with over pressure signs?

ADDED:

7mm08 Tikka Stainless. Think it was the brass. I don't use RP for at least four years now. I'm not sure how that one got loaded... and I didn't notice it was RP until I posted this picture (can we all say "Blind as a Bat? LOL). Went back after posting this to see some other loads and RP used - 5 of them. Already disassembled... but I threw away 6 good brass earlier I'm sure. It kinda scared me as I have never had this happen before.

I was working a 120 TTSX with N140. 43.4, 43.7, 44.0 (case issue), 44.3 (did not shoot). If anyone can provide a quickload review before I try again it would be greatly appreciated.


and... the primer was pierced.

 

[rkb21]

Looks like hard brass and not excessive pressure .Do you anneal your brass how many times have you used this brass

 

[fkimble@charter.net]

That ain't a pressure issue! Looks like large necked factory chamber with over worked neck sizing. Tell us more.

Frank

 

[fkimble@charter.net]

Too bad you chunked those other brass. Would have liked to see those cases, side view and head view. Oh I'd clean your chamber good.

Frank

 

[Rocketvapor]

Is that primer pierced ? Or just a shadow.
Tell us about the charge and projectile.

 

[JSH]

A split neck…….yeah some soot on the neck, that happens when brass splits.
I also am thinking over worked, hard brass.
Even if it was annealed, and what I see and the post means little. A small scratch can lead to that over time.

 

[bfiles]

Bruv, that’s a split neck. More likely from your brass prep process than over pressure. If they look like this you are closer to a problem…although not necessarily. These are just OLD (18 reloads) not over pressured.

 

[bfiles]

Unless that’s a pierced primer in which case, something ain’t right.

 

[Rocketvapor]

Some details would likely help us help you.

Someone mentioned 'overworked brass'.
Take a cheap set of calipers and measure 'as fired' neck below the split (or another case if fired about same number of times, in the same chamber, and same headstamp).
Using same calipers measure another case run through your sizing die WITHOUT mandrel.
Install mandrel.
Now measure the same case with the same calipers expanded by your process.
One more measurement on the neck with a projectile seated.
This gives you sized, expanded, loaded, and fired neck diameters.

Someone with a 7-08 can comment on your load.
What primer is that. Looks brassy. WLR?

 

[HuntClub]

Some details would likely help us help you.

Someone mentioned 'overworked brass'.
Take a cheap set of calipers and measure 'as fired' neck below the split (or another case if fired about same number of times, in the same chamber, and same headstamp).
Using same calipers measure another case run through your sizing die WITHOUT mandrel.
Install mandrel.
Now measure the same case with the same calipers expanded by your process.
One more measurement on the neck with a projectile seated.
This gives you sized, expanded, loaded, and fired neck diameters.

Someone with a 7-08 can comment on your load.
What primer is that. Looks brassy. WLR?

Primer is Rem 9 1/2 LR (not magnum)

 

[Zero333]

What COAL are you seating them 120 TTSX at ??

In the 7-08rem, Quickload shows 44 gr of N-140 beneath the 120 TTSX @ 2.800" coal = 62,569 psi

That's with brass that holds 55 gr of H20... and the120 ttsx bullet length of 1.219"
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Remember... This is just Quickload and not unlike any other manual.. Thus take this with a grain of salt...
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[6BRA]

Looks like necks are turned thin, from picture there appears to be a large edge at shoulder junction, indicating turned pretty thin.

 

[diggler1833]

I split about 70% of my necks on LC 5.56 brass (that day only) after three hot reloads (25.5gr Re-15 under a 69gr SMK) WITHOUT ever annealing. Accuracy wasn't really any worse than normal...went from 1/2 MOA to about 2/3 that day.

Ruined ~50 pieces of brass, and made me a believer in annealing. Lesson learned, and I either anneal after every single, or second firing...depending on the cartridge I load for.

Hasn't happened since.

 

[Homerange]

7mm08 Tikka Stainless. Think it was the brass. I don't use RP for at least four years now. I'm not sure how that one got loaded... and I didn't notice it was RP until I posted this picture (can we all say "Blind as a Bat? LOL). Went back after posting this to see some other loads and RP used - 5 of them. Already disassembled... but I threw away 6 good brass earlier I'm sure. It kinda scared me as I have never had this happen before.

This implies mixed brass was used. Was it ?

 

[209jones]

Mixed brass, old hard brass, load is definitely probably getting up there in pressure, probably not showing if that was the first round at that chg wt, due to the pierced primer/split neck. VV shows N140 @ 44.8 max with a 120 Sierra cup & core bullet, most likely ought to reduce that a bit for a TTSX. No idea what speeds you got as you didn't say, could tell a tale too, next try, with new brass and that load. Might be asking Barnes on that one.

 

[6.5 forever]

That ain't a pressure issue! Looks like large necked factory chamber with over worked neck sizing. Tell us more.

Frank

This∆∆∆∆∆

 

[K22]

Doesn't look like any pressure surge I ever saw. All the ones I experienced resulted in hard bolt lift, and an ejector mark on the case head.

Flatten primers are not an absolute sign of a pressure surge but can be.

Split necks are a result of work hardened brass, mechanical fatigue, not pressure.

A pieced primers are not an absolute sign of pressure either, can be due to a firing pin issue.

 

[jelenko]

Just for reference.
I don't anneal. I start to get split necks after 3-4 reloads in 223 with loads that are in the low 50K pressure range - i.e., it will happen.

 

[K22]

Just for reference.
I don't anneal. I start to get split necks after 3-4 reloads in 223 with loads that are in the low 50K pressure range - i.e., it will happen.

I don't anneal either and I get 15 to 18 reloads out of my 223 cases bolt rifles only. However, I use only virgin cases dedicated to a specific rifle, rotate their use.

I use a range of sized and polished my expander buttons to reduce drag on the necks so as to not over work the case neck. I also nylon brush the inside of the necks to remove and excessive residue to reduce drag on the neck. Lubing the inside of the necks will also help but I don't need to do that due to the polished expanders.

 

[jelenko]

I don't anneal either and I get 15 to 18 reloads out of my 223 cases bolt rifles only. However, I use only virgin cases dedicated to a specific rifle, rotate their use.

I use a range of sized and polished my expander buttons to reduce drag on the necks so as to not over work the case neck. I also nylon brush the inside of the necks to remove and excessive residue to reduce drag on the neck. Lubing the inside of the necks will also help but I don't need to do that due to the polished expanders.

Interesting
All mine are on an ar. Would that make that much difference?