split necks

[okie]

what causes them? My neck measures about .277---loaded rounds avg. .274 ------these cases are splitting after I run them through a fl sizer after being fired only twice---(I noticed splits when bullets were being seated on 3rd load---some just dropped in) this is norma 6.5-284 resized to 6-284. Any suggestions?---rechamber to something more conservative?? thanks

 

[RonAKA]

Did you anneal them after resizing to 6-284? Split necks are usually caused by work hardening of the brass, without sufficient annealing.

 

[okie]

no, I just supposed that new brass could take it---seems like a lot of trouble, but this is my first go at this cartridge

 

[RonAKA]

My guess would be that you should be able to get away with it too. My standard supply of .264 WM is just necked down 7mm RM cases. Same 0.5mm reduction, and I do get away with it. My cases do eventually fail with a split neck though, but not after 3 reloads.

That said, your brass is clearly telling you that you can't get away without annealing it.

 

[Kenny474]

Are you using the expander in the FL die, and what does the die size the neck down to if you don't use it? The issue with many FL dies is that they size the neck far more than necessary and then allow the expander to give the final neck ID. They do this to compensate for brass with inconsistent neck thickness, as this method allows inconsistent brass to all be sized with the same ID.

If you are using dies that are overworking the brass, switch to a better system, such as a body die and bushing neck die or a full length bushing die. Now you can control how much the necks are worked and not allow them to be excessively worked each loading.

Annealing can help a bit, but splitting after two loadings is a bit fast. I would address the sizing system first and then look into annealing your brass so you can solve the root of the problem and not just put a band aid on it.
Annealing needs to be done when you size a case excessively, such as going from .284 to .243, but .264 to .243 isn't so bad it should cause cases to split that fast. That is why I feel there may be an issue with your sizing method.

Have all your brass annealed by one of the companies that offer that service if you don't already do so, as it takes a bit to get the hang of it and you already have one issue that needs solving.

 

[Yellow11]

I can't offer any useful comments, but, for what it is worth, I travel a similar route with a pair of 6x47 Lapua. I use Lapua brasses and, like yourself, I am resizing to 0.5mm less that they were manufactured.

I have load and reloaded well in excess of 2,000 rounds but have never had your problem.

Since we know that resizing should be fairly trouble free, have you tried alternative brand/batches of brasses or an alternative die.

I assume you have offered up lubrication where appropriate?

 

[okie]

Ron, I agree--it seems tedious ----- Kenny, yes I am using the expander--I took it out and measured a neck---I honestly do not remember what it took it down to, but it did not seem an excessive amt., I will measure it tonight------I am currently getting away with this with lapua brass in a 6-6.5x47L------ Yellow, I am thinking It might be the norma brass---I prepped some lapua last night to try out. I think that it would be too expensive to keep this up, I plan on using this for a long range prairie dog rifle, and I wanted a no-maintenance, easy to prep for, fairly high volume shooter---I do not mind annealing, I just do not want to do it this often--(I guess I do mind it!)

 

[RonAKA]

My guess would be that if you annealed after sizing down to 6 mm, then you could get away without doing it for another 10, and if you don't care about getting the max out of your brass, then don't even do it at 10. You may get 20. I certainly work my 264 brass to the max with FL sizing, and using an expander ball. I still get up to 20 loads without annealing.