7mm08

21 October 2003, 12:23

LE270

I've had case necks split, but rarely after so few firings. My first suspicion would go to the brass itself.

What kind of brass are you using? See if you can get a different brand or a different lot of the same brand of brass, and then see if that solves your problem. You may just have a bad lot of brass.

This may also be a sign that your loads are excessively hot.

If it's only a few of your loads -- say one in ten or fewer -- I'd throw those cases out and continue with the loading and shooting. If it's a lot of them -- say 25 to 50 % -- I'd suspect that something more serious is amiss.

21 October 2003, 12:30

d l

thanks for the reply. i have a friend who has a new rem.700 in the same caliber and he has the same problem. i'm using a load of 40 gr. of imr4350 and a 139gr hornady bullet this is a middle of the road load. i'm using rem.new brass my rifle has been fired a lot,but his is new.

21 October 2003, 14:09

LE270

Here's another possibility: Maybe Remington is cutting the part of the chamber into which the neck of the cartridge fits too loose.

But I must admit that this is only an off-the-top-of-the-head suggestion on my part because I don't know for sure whether, if this were true, it would really result in split necks.

21 October 2003, 14:17

LE270

quote:
Originally posted by d l:
i have a friend who has a new rem.700 in the same caliber and he has the same problem.

Are you and he using the same reloading dies, or a different set? If they are the same, I'd try a different die set.

Are you and he using brass from the same lot? If so, I'd try different brass.

If you can't figure out any other reason why this is happening, I'd also suggest switching to a different bullet from a different manufacturer to see whether that makes a difference.

21 October 2003, 14:53

<Savage 99>

Good advice above. What brand of brass are you and you friend using? What is the diameter of a neck from a fired case? What is the diameter of a sized case neck?

What brand of dies?

21 October 2003, 15:05

Ol` Joe

The load won`t split necks. 40 gr of IMR4350 with the 139 gr Hornady is acually under recommended starting in my manuals for the 708.
Split necks are caused by over working the brass in my experiance. I would suspect the die is the problem if both you and your friend are useing the same one. If you both are haveing the same problem and useing different dies I would look at the brass as not being properly annealed (poor lot)or in need of annealing (over worked). Somewhere the case necks are being work hardened, you`ll have to do some measuring to find out where. Check a fired case, the neck shouldn`t be more then ~.315 at the mouth. Try sizeing with out the expander in your die, mine come out of my Redding at .307". The case with a bullet measures .311 on my 708s. If your cases measure notably lesser or greater then these figures I think you`ve found your problem.

22 October 2003, 09:24

d l

hi ol joe i'm sorry,i listed the load as 4350 when it was accually 40 grs of imr4064 with a 139gr hornady bullet. we are both using RCBS DIES,HE HAS A SET AND I DO ALSO. the cases mic .0310 before firing to about .0315 after. we are using remington brass

22 October 2003, 10:10

safarihunter

I think Savage99 and Ol" Joe have it right. I had similat problem with Ruger #1 in 7X57.

Mike the neck of a fired case and mike the neck of a sized case and see what the difference is.

22 October 2003, 10:50

KevinNY

Remove the expander assembly in your sizing die and size a fired case. Now measure the outside diameter of the neck vs. a case you sized with the expander assembly back in the die. I think you will find this is where your problem is. If its much over a .010 difference the die is overworking the brass and hardening it. I had the same problem with Lee dies for a 300 WSM. Five firings and split necks, went to a redding full length bushing die with the expander removed and have 10 firings on cases that are still fine. In my case the difference in measurements was .017 with the Lee dies.

[ 10-22-2003, 01:51: Message edited by: KevinNY ]

22 October 2003, 12:43

d l

keviNY i tried what you said and the dif.was .308 with expander and .302 without. thats only .006 i guess it could be a bad lot of brass

22 October 2003, 13:03

d l

ol joe my measurements seem quite in line with yours. i really appreciate all you guys help. hope i can come up with an answer

22 October 2003, 13:59

Ol` Joe

dl, Your about .005 smaller with your sized cases with the expander out. Mine ran .307 you are at .302 according to your last post. The fired case does match mine at .315".
You are looking at ~.013" of working with your dies compared to .008 that I see with mine. That could be your problem. I`d call RCBS and talk to them about it. They are real good about helping their customers and have modified a die for me once that I was haveing trouble with at no charge.
1-800-533-5000 should get you in touch with a tech.........hope they can help.