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
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