Split Necks on Lapua 6.5 CM SRP Brass

[RRW]

Just noticed today a couple of split necks. Brass has eight firings and never annealed. Load is 42 gr of H4350 with 139/140 gr bullets. Using Redding Type S Full Length die with a .288 bushing. A loaded case measures .292" so not sure if that would make a difference considering the brass has not been annealed. First time seeing this, any opinions appreciated.

 

[rijndael]

What is the fired neck diameter? I’m curious how much it’s being moved in sizing.

Regardless, annealing would likely avoid it.

 

[TheOfficeT-Rex]

Eight firings? That will happen. Cull them and move on unless you want to start annealing.

 

[RRW]

Thanks for the info. Will measure the fired neck diameter tomorrow. Won't be using that lot of brass anymore, its going in the trash. I am not currently annealing but may have to start.

 

[straightshooter1]

Just noticed today a couple of split necks. Brass has eight firings and never annealed. Load is 42 gr of H4350 with 139/140 gr bullets. Using Redding Type S Full Length die with a .288 bushing. A loaded case measures .292" so not sure if that would make a difference considering the brass has not been annealed. First time seeing this, any opinions appreciated.

Annealing would have defiantly extending the life of that brass. As I see it, you have two options:

1. Start annealing your brass and do it as part of your regular processing procedure (like every firing, or at least every 3rd firing).

2. Reduce the amount of work your sizing die does on your brass so that the work hardening is minimized. This can be done by changing the amount of reduction your die does to the brass by having the die's neck area reamed to a larger diameter. If you're using an expander ball in your die, you'd probably have to make some adjustment with it to do the job right.

3. You can do all the above as annealing and reaming the die helps a lot with your sizing process.

 

[Shoots 700's]

8 firings and no annealing, sounds like you got the expected life out of them. Start annealing every firing

 

[RRW]

What is the fired neck diameter? I’m curious how much it’s being moved in sizing.

Regardless, annealing would likely avoid it.

Thanks again for your help guys. Loaded case measures .292" and fired neck diameter is .293.5"-.294". Time to move on to a new lot of brass and consider annealing if I want to get more brass life.

 

[FNG1001]

Show us the brass

 

[straightshooter1]

Thanks again for your help guys. Loaded case measures .292" and fired neck diameter is .293.5"-.294". Time to move on to a new lot of brass and consider annealing if I want to get more brass life.

It's not that difference in those dimensions that works the case necks so hard. It's how far your die squeezes the neck down before it's expanded to your sized dimension. Like, your die probably squeezes the neck down to somewhere around .285 or so before being expanded.

 

[Thump_rrr]

Thanks again for your help guys. Loaded case measures .292" and fired neck diameter is .293.5"-.294". Time to move on to a new lot of brass and consider annealing if I want to get more brass life.

I would try a .290 bushing.
Redding suggests starting at around 0.002 below loaded neck diameter.
I'm using the same brass and die as you and that's the one I use.
I also anneal every 2nd or 3rd time.