.338 Lapua Splitting necks.

[4xforfun]

A friend of mine brought over his Armalight AR 30 in 338 Lapua Magnum. I had developed loads for this thing about 5 years ago using 250 SMK's. I am thinking we are on the 5th firing on this 50 pieces of brass. Trying out the new 300 Grain Berger..(BIG FUN!!). I am now loosing about every third case due to the neck splitting right at the neck/shoulder juncture. Some are itty bitty cracks...just getting started....others are split all the way from the sholder to about 1/32 inch from the case mouth. I am pretty sure the first 4 sizing's were neck only using a standard redding die. I FL sized them this time because the bolt is getting a touch hard to close. I know that when I neck size I only go about 3/4 to 4/5ths down the neck. I was doing a little measuring. Sized cases are .3640. Loaded rounds are .3660, so It looks like we are not oversizing the brass. The problem I see is that it looks like a fairly generous factory neck....fired rounds measure up at .3750. Now, I guess that I am guessing that the neck is generous...I could be wrong.

Could there be any other explanation other than over working the brass? I'm pretty sure that I will anneal whats left after I fire them.

Any insight would be appreciated.

Thanks,
Tod

 

[watercam]

I seem to have the same issue w/ Lapua .243 brass. The good news is it is a bit stronger, that bad is it gets brittle after three or four firings. Started annealing after every third firing and problem went away.

 

[fullersson]

I would also suggest trying to anneal more often. That brass is too expensive to be throwing away. Brian Brown.

 

[alf]

Anneal it....every time.......

 

[TrapperT]

I shoot the .338 LM on a regular basis and anneal approximatley every third firing. My chamber is probably a little tighter than yours, but I have 11 firings on Lapua brass and they are running just fine. I also shoot the 300gr bullets at 2830fps, so I'm not easy on the brass. Primer pockets are still rally good to.

 

[amlevin]

I don't find it surprising that .338 Lapua is splitting necks.

Whenever some shoots their .338 next to me I end up with a splitting headache especially if it has a huge muzzle brake that directs most of the blast my way

 

[queen_stick]

Question for those who anneal every 3rd or 4th or etc.. time:
Q= How is your consistency to accuracy and ballistics when you go at it like that?
Q= Say one that is shot at a fresh annealing and one that is at 3 cycles out, how do the POI's compare to each other?
(say at 800yds)

Question for those who Neck-size only for 3 or 4 or etc.. times and then resize:
Q= How is your consistency to accuracy and ballistics when you go at it like that?
Q= Say one that is shot at a freshly F/L and one that is at 3 cycles out, how do the POI's compare to each other?
(say at 800yds)

Thanks for the inputs !!!!!
Donovan Moran

Interesting question Donovan. I don't have the answer, but I can say that A LOT of successful 1K yard competitors FL size and anneal after every firing. I don't believe your POI would change at all, but I could be wrong. Although, there's a very good chance that your vertical spread will shrink if you FL size and anneal every time. Unless you have luck like mine... Every time I try something to reduce vertical, I end up making it worse

I'd be interested in seeing your results if you test that out for yourself.

Walt

 

[queen_stick]

That's very interesting, Donovan. Gave me something to think about...

Walt

 

[GNERGY]

I noticed for those of us that don't use neck bushing die sets, most of the dies nowadays resize the neck more than it needs to be then the expander ball opens it up on the way out of the die working the brass twice right there. I put a bullet in a case and measure the neck OD and hone my sizing die to give me .003 neck tension ( neck dia. .003 smaller than loaded dia. ) I also noticed that I don't have to trim my cases as much because most of your case stretch happens when you are pulling your case out of the resizing die over the expander ball or mandrel ( some people call it. ) I also anneal about every 3rd firing.
Good Luck
Tarey