Cracked shoulder

[Dave M.]

6 dasher
3048fps MV, 33.1g RL-15, Berger 105g VLD target.
Lapua 6BR brass fire formed to 6 dasher. Shooting normal load at outside temp of 30F this morning in a 600 yard F-Open competition. Same load for the last 1250+ rounds.
12 firings on this brass. Annealed after each firing. Full length sized with a Whidden gun works bushing die (.265” bushing) .271” chamber neck and .2685 loaded round. Have never lost a single piece of brass due to cracks and I inspect 100% of my brass before reloading. Threw a”9” this morning that was 4.5” low and 5.5” left of the rest of my shots. So I put that piece of brass underside down in my loading box. This is what I found when I got home and inspected my brass….


Crack is so perfectly vertical that it looks like it was cut with a dremmel wheel. You can see the carbon blowout all around the crack.
Dave

 

[Straightshooter1]

6 dasher
3048fps MV, 33.1g RL-15, Berger 105g VLD target.
Lapua 6BR brass fire formed to 6 dasher. Shooting normal load at outside temp of 30F this morning in a 600 yard F-Open competition. Same load for the last 1250+ rounds.
12 firings on this brass. Annealed after each firing. Full length sized with a Whidden gun works bushing die (.265” bushing) .271” chamber neck and .2685 loaded round. Have never lost a single piece of brass due to cracks and I inspect 100% of my brass before reloading. Threw a”9” this morning that was 4.5” low and 5.5” left of the rest of my shots. So I put that piece of brass underside down in my loading box. This is what I found when I got home and inspected my brass….
View attachment 1330478View attachment 1330479

Crack is so perfectly vertical that it looks like it was cut with a dremmel wheel. You can see the carbon blowout all around the crack.
Dave

What do you use to anneal your cases?

It could be that you're not annealing your cases as much as you think. . .??? ¯\_(ツ)_/¯

 

[SeabeeKen]

The bottom of the crack is interesting. Almost looks like it was center punched. A ding perhaps. Not sure that had anything to do with it, just seems odd

 

[boltfluter]

I would say a factory defect that finally gave up and let go. RIP.

 

[mudduck]

I have 6 pcs of new lapua that like that. Was told that they crack sometimes when forming them. Couple of them you can’t see with out magnify.

 

[Webster]

6 dasher
3048fps MV, 33.1g RL-15, Berger 105g VLD target.
Lapua 6BR brass fire formed to 6 dasher. Shooting normal load at outside temp of 30F this morning in a 600 yard F-Open competition. Same load for the last 1250+ rounds.
12 firings on this brass. Annealed after each firing. Full length sized with a Whidden gun works bushing die (.265” bushing) .271” chamber neck and .2685 loaded round. Have never lost a single piece of brass due to cracks and I inspect 100% of my brass before reloading. Threw a”9” this morning that was 4.5” low and 5.5” left of the rest of my shots. So I put that piece of brass underside down in my loading box. This is what I found when I got home and inspected my brass….
View attachment 1330478View attachment 1330479

Crack is so perfectly vertical that it looks like it was cut with a dremmel wheel. You can see the carbon blowout all around the crack.
Dave

Interesting to follow this one. Waiting to see explanations. Seems strange that the shoulder cracks and not the neck. Also it seems strange that the crack has so much width. Been reloading for 50 years and never heard of this before. Why would the crack terminate with rounded edges at the neck/shoulder and shoulder body?

Later:
Saw images of cracked necks on internet. They looked the same as the cracked shoulder. Wide opening and rounded at the ends of the crack. Any neck cracks I had appeared to start at the end of the neck and go inward.

 

[Dave M.]

What do you use to anneal your cases?

It could be that you're not annealing your cases as much as you think. . .??? ¯\_(ツ)_/¯

I use an induction annealing machine that I built. I spent 8 years working in the induction industry and I’m certain my annealing is on point because I’m now in OEM automotive business and I have access to a full metallurgy lab at work. My annealing program has been dialed in perfectly. I’m thinking that even though I’ve done all this, I’m just starting to hit the wall after 12-13 firings with overall brass working brittleness. I’ve fully inspected all of my brass from the competition yesterday and located 4 other pieces (5 pieces total out of 83 shots) with small hairline cracks in the body of the cases, no other pieces showed any signs of cracking in the neck or shoulders (pics shown below). I plan to section these and get some data from them in the future.
Dave

 

[rsbhunter]

I'm thinking that you have reached the point where the brass has reached the end of its life span. Like bbl's, I figure that brass has a point where it's done.....it's a consumable .....as much as I hate to dispose of brass, if it has given great results on target....it is more than worth the replacement cost.....rsbhunter

 

[243winxb]

fire formed

12 firings on this brass.

New brass time, my guess.

Have seen new factory 30-06 ammo split the same way.

 

[Bocephus]

I was an induction annealing machine that I built. I spent 8 years working in the induction industry and I’m certain my annealing is on point because I’m now in OEM automotive business and I have access to a full metallurgy lab at work. My annealing program has been dialed in perfectly. I’m thinking that even though I’ve done all this, I’m just starting to hit the wall after 12-13 firings with overall brass working brittleness. I’ve fully inspected all of my brass from the competition yesterday and located 4 other pieces (5 pieces total out of 83 shots) with small hairline cracks in the body of the cases, no other pieces showed any signs of cracking in the neck or shoulders (pics shown below). I plan to section these and get some data from them in the future.
Dave

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Well, this may be way above my pay grade, but the pics make me think maybe F.O.D. in the chamber. Actually looks like small pieces of brush bristles imbedded in the cases.
Apologies if that dog is barking up the wrong tree.

 

[Dave M.]

I'm thinking that you have reached the point where the brass has reached the end of its life span. Like bbl's, I figure that brass has a point where it's done.....it's a consumable .....as much as I hate to dispose of brass, if it has given great results on target....it is more than worth the replacement cost.....rsbhunter

I agree 100%

 

[Dave M.]

Well, this may be way above my pay grade, but the pics make me think maybe F.O.D. in the chamber. Actually looks like small pieces of brush bristles imbedded in the cases.
Apologies if that dog is barking up the wrong tree.

I don’t think so because I’ve borescoped it after cleaning and didn’t find anything. I also didn’t have this issue the last time I shot this gun two weeks ago and fired a clean 400-30X and I didn’t clean it between those two weeks before yesterdays competition

 

[Bc'z]

I don’t think so because I’ve borescoped it after cleaning and didn’t find anything. I also didn’t have this issue the last time I shot this gun two weeks ago and fired a clean 400-30X and I didn’t clean it between those two weeks before

You shot 2 matches without cleaning?

 

[Bocephus]

I don’t think so because I’ve borescoped it after cleaning and didn’t find anything. I also didn’t have this issue the last time I shot this gun two weeks ago and fired a clean 400-30X and I didn’t clean it between those two weeks before yesterdays competition

Understand your point. Just that the randomness and impressions sure look that way. On at least two occasions I’ve had a pulled strand of a patch that was missed after cleanup leave an impression in a case.
Maybe fire those with the marks again just to see if the impressions iron out?

 

[rsbhunter]

The marks on the cases are a mystery ? But , aside from that, the cases just need to be retired. NOT to hijack your thread, but how many firings do you think a case is good for? What is the general consensus of firings a lapua case, pushed to normal full pressure loads, will last? I ask because I use Norma cases for my 6mm Norma Dasher rifles, and have 5-8 firings on those, and other calibers that use Lapua brass. rsbhunter

 

[K22]

Wow, never seen anything like this. I've had a few cracks in the shoulder area with 243 Win, Federal cases but these were irregular in shape and not opened to the degree like the one in your post.

I wouldn't expect such a failure after 12 reloads unless you're loading at maximum pressure but even so, the size and shape of this crack baffles me. I normally get about 15 reloads but I don't load near max pressure. Also, almost always, the first signs of case failure I encounter is in the neck with neck splits.

It almost looks like there was something trapped in the chamber in that area and the pressure again that foreign object created a stress riser. But you said your rule the possible of a foreign object out.

Will be tracking this one to see what other say.

 

[rsbhunter]

I have had new, just fired cases split like this, and never did figure out the cause....these are 6 mm ARC cases (necked down 6.5 Grendel) that I had formed and fired out of an ar. I formed and fired 50 cases, and these are the only 4 that split.(only 3 in pic)..other cases had no signs of stress or failure...the shooting gods have a weird sense of humor.....rsbhunter

 

[Dave M.]

You shot 2 matches without cleaning?

I do sometimes Brett. My gun hates a thorough cleaning. It’s strange like that. I shot 400-30X at 600 yards 2 weeks ago and 399-21X yesterday, the the lone “9” being the cracked shoulder case. 4 weeks ago, I thoroughly cleaned my rifle and shot in a 600 yard competition. I fired 393-13X but the first 30 rounds were all over the place (shot 193-4X followed by a 200-9X), and that day it was cleaned very thoroughly. Just likes to be shot about 20-30 rounds fouled. But it also has over 2100 rounds on this barrel.
Dave

 

[fkimble@charter.net]

RSBhunters pic looks like the occasional split/crack I run across. Seen it in various brands of brass, from 38, 357, 41mag, 223 and 308. I always just assumed it was a slight internal/not visible flaw that finally gave it up.

Frank

 

[swd]

It’s rare but I’ve had it happen. It was probably a defect in the brass that finally gave way. Don’t worry about it and keep shooting..