308 split case ?

[hammer33]

First season hunting with 308. Buddy has the same rifle so I decided to try his reloading recipe.
40 gr IMR 4064 with a hornady 180gr sst. Slight crimp into the cannalure. Speer book has 39gr min to 43gr max.
Upon cleaning the brass I noticed 4 split case necks out of 20. Brass has been reloaded a max of 3 times.
Slight flattening of the primers which I wouldn't expect from a mild load of 40gr.

Where should I start my detective work to determine the cause? Thanks.

 

[Jcalder]

The brass

 

[hammer33]

The brass

 

[Jcalder]

I've seen new brass split just the same as brass loaded 10 times. Wasn't really trying to be a SA. Some of it is work hardened. I think sometimes they have bad place. It's just a place that fails.

 

[hammer33]

I was shocked at the failure %. Should I look into annealing the brass?

 

[Jcalder]

I was shocked at the failure %. Should I look into annealing the brass?

It would probably help

 

[Remi]

I was shocked at the failure %. Should I look into annealing the brass?

I've had new Winchester brass split in the bag. Anneal it

 

[TnKen]

I've had new Winchester brass split in the bag. Anneal it

Me too 7mm mag

 

[MUP]

I was shocked at the failure %. Should I look into annealing the brass?

Yes. I've shot 300 WinMag RP brass up to 7 times, but have annealed it after 3 firings to get there.

 

[Remi]

Me too 7mm mag

Mine was 7wsm


I have cases I've shot 30 times but I anneal every 3 and my shoulder set back is .002" to reduce working the brass.

 

[DaveB]

Case neck split is nearly always overwork.

I never crimp my centerfire bolt guns. I am nearly always at max recommended charge weight and very rarely at SAAMI overall length. Jump is bad for accuracy. Do not engage the lands keep to .007 or a bit more.

Annealing is a very good way to extend case life.

Good place to get once fired 308 brass of quality is brassmanbrass . I have 500 of their FC match grade 308 brass and so far extremely good results. I also have quite a few R-P brass but those seem to be extinct.

My dislike of Hornady brass from here on

If it is Hornady brass just toss it. Eyeball the primer holes. Hornady seems to like oblong holes slightly off center.

 

[hammer33]

Going from memory but I think its a bag of once fired Remmington brass I got from Cabelas a few years ago.

 

[fairchaser]

Why do you crimp? There sb plenty of neck tension to handle most any rough hunting situation. I think this is the source of your split necks. Crimping puts a lot of tension on the neck. If you happen to be jamming your bullets as well, this will certainly cause split necks.

 

[Remi]

As to the flat primers, if you're pushing the shoulders back too far you're creating excess headspace which will let the primer back out slightly then flatten as the brass slams into it as it expands. Reading primers isn't a good indication of over pressure.

 

[hammer33]

Why do you crimp? There sb plenty of neck tension to handle most any rough hunting situation. I think this is the source of your split necks. Crimping puts a lot of tension on the neck. If you happen to be jamming your bullets as well, this will certainly cause split necks.

Crimping is a habit I guess from loading 7 mag rounds. At the end of the season, the cartridge in the bottom of the magazine that didn't get used, would be seated deeper from all the recoil. Someone recommended a light crimp which solved that problem. ( and not topping off the magazine after every shot, leaving that same cartridge in the mag all season)

 

[infoman jr.]

I was shocked at the failure %. Should I look into annealing the brass?

Yes