need help with .308win strange problem

[C.J]

i was working up loads for my new rem 700 .308win using win once fired (factory) brass, win standard primers, hodgdon varget powder, and 180 hornaday interlocks as well as 180gr nosler accubonds for bullets. i loaded 20rds started at where the book said too 39gr of powder and went up to 42gr the max is 43.5gr. i was shooting the hornaday bullets first to get rid of them and noticed that the primers were backing out of the pocket slightly they were not flattened or anything just backed out, i thought this was weired cause i was at the suggested start grains. i switched to the accubonds to see if this would still happen and it did not. i have never had this problem before the gun didnt do it with factory loads. i was thinking it was that the hornaday bullets were not deep enough in the case although they were seated to recommended overall length. also one of the cases necks split slightly at start load with hornaday bullets, maybe the cases are bad? i would really appriciate any advise on this.

[BloomGrad]

This problem you post sounds like the same problem I have with my Rem 700 classic .35 Whelen from 1988.  I've owned this rifle new in box from late 1989? or 1990.  My cases have the same conditions.  Including the neck splits.  Check if your dies are moving the shoulder back excessively during reloading.  I try to set my RCBS dies to neck size or just a little more.  No more than that.  Try Rem brass and Rem primers as a pair.  If it still happens try different brands of primers.  CCI seems to have harder cups and may not back out.

I have always wanted to check the headspace on my 700 but have never done it.  But it may just be an oversized reamer with a large diameter neck dimension was used.

I can get 2 or 3 loadings out of my Rem brass for the Whelen.  I think that is ok for me.  I buy the brass in packs of new 100 Rem cases.  I throw out the brass if any in the set of 20 cases show any slight splits.  This keeps me from wondering which boxed group or set is old or new.  Until they split they seem very safe as all show no signs of too much pressure.

I asked the Rem service rep at the NRA show years ago and he said I could send the rifle back But I chose not to.  He asked if the factory loaded rounds did the same and I said No.  He said that if the factory rounds had more pressure than my starting to medium loads It might just be my reloading steps, settings or choice of components.

I don't shoot this rifle much except to hunt or practice for the hunt.  So I have lived with it as a factory load does fine and my loads are safe.  It sure does shoot fine.  1" to 1.25" on an average day so why mess with it?     

[STexhunter]

Just some ideas.  Check the over length of you cases.  Make sure your primer pockets are tight.  I know that the ogive of the bullets are different.  Also check the end of your cases and make sure they are flat  Any slight bend from the extractor etc. will cause a very small difference in the headspace.  Just my 2 cents worth.

[STexhunter]

Just some ideas.  Check the over all lenght of your cases.  Check and make sure the primer pockets are tight.  I know that the ogive of the bullets are different.  Also check and make sure the end of the cases are flat.  Any bend from extraction etc.  will cause a slight difference in headspace.  Just my 2 cents worth.

[jcunclejoe]

What you have there with the primers backing out it is excessive headspace in relation to your brass headspace dimension. If you have adjusted your dies per the manufacturers instructions you are most likely setting the shoulder back too far. That allows the case to move forward with the firing pin strike until the shoulder contacts. As pressure builds in the case the neck expands and grips the walls of the chamber holding the case in the forward position. As the pressure is building the primer backs out to contact the breech face.
Since this is a starting load, the pressure in the case is on the low side and there was not enough pressure to stretch the case to the breech face and at the same time re-seat the primer.  So you are left with primers backed out. That is good in a way because only one or two of these stretchings will ruin a case as it will thin around .200 -.250 in front of the forward edge of the extractor cut and eventually you will see that horrible shiny line indicating insipient case head seperation.

It is easy to check for sure about your die adjustment/headspace. Take a small piece of 1/2" thick steel or aluminum maybe 1/2"-3/4" square and drill a .375 hole through the middle. Lightly break and lightly polish the edges of the hole on both sides. Then slip this block over one of your fired case necks that did not have the backed out primers. Then you can measure over the case and the block and then set your dies to move the shoulder back no more than .002 to .003. This tool/block will also work on most any cartridge based on .308, 30-06, BR and magnums .338 and under.

The split neck was most likely a flaw in the brass and not related to your headspace issues.
Good luck and I hope this information is of some help to you.
Joe

[steve4102]

  Weak loads (starting loads) can sometimes cause the primers to back out a bit.  Increase the charge and see if they stay in place.

[PaulS]

  Weak loads (starting loads) can sometimes cause the primers to back out a bit.  Increase the charge and see if they stay in place.

This is the most likely cause - I was going to post it but Steve beat me to it. You can take your gun in to any gunsmith and have the headspace checked but mt bet goes on light loads  - not enough pressure to push the case back against the bolt face (which pushes the primer back into the case)

The problem will disappear as you increase the powder charge. After you fire them, neck-size your cases about 2/3 down the neck and you will never have a problem unless you exceed the limits of your gun.

[PaulS]

This problem you post sounds like the same problem I have with my Rem 700 classic .35 Whelen from 1988.

I can get 2 or 3 loadings out of my Rem brass for the Whelen.  I think that is ok for me.  I buy the brass in packs of new 100 Rem cases.  I throw out the brass if any in the set of 20 cases show any slight splits.  This keeps me from wondering which boxed group or set is old or new.  Until they split they seem very safe as all show no signs of too much pressure.

the Rem service rep asked if the factory loaded rounds did the same and I said No.     

If factory loads don't cause the same results - and you are using loads that are within safe pressure limits you should be able to get many more than 3 loadings. Factory loads are usually shorter than reloads unless you are using ultra-small base dies. What is the load that you are using? Maybe we can figure out your problem and get more life out of those cases.

[jgalar]

You do not have a problem! The primers backing out is caused by low pressure.

[jcunclejoe]

It's good to see that we all agree that low pressure is happening here. But there is also a headspace condition going on due to the difference in the chamber headspace dimension and the case headspace dimension.

If the headspace is correct (cases sized properly to fit the chamber) and there is low pressure, the primers will not back out. It requires a combination of excessive headspace and low pressure to back primers out. Increasing the pressure without adjusting the dies will just stretch the cases and significantly shorten the brass life.
The dies need to be backed off the proper amount to solve the problem. Then the load can be carefully worked up.

Thanks
Joe

[rickt300]

In my bolt rifles I usually size the cases to where the neck sized line is just in front of the shoulder resulting in sort of snug chambering. Seems to be good for accuracy too. What everyone else says here sounds right to me.

[jgalar]

If you have normal headspace around .003-.004 you still have .003-.004 space that the primer can back out untill it contacts the bolt head. The primer backs out in every cartridge fired, it is reseated when the case expands from higher (normal) pressure. If you shoot weak pressure loads with the same case you MAY create excessive headspace on a rimless case as the shoulder is pushed ever so slightly back upon firing and there isn't sufficient pressure to expand the case back to proper dimensions. Rimless cases that I use for reduced and cast bullet loads are never used for normal pressure loading.

[PaulS]

I know that i don't have headspce problems with my 3006 but I have had primers back out from low pressure before. This is even more likely to happen if your flash holes are larger. I got the bright idea to uniform all the flash holes to the same size and ended up throughing cases away.(about 100 of them) Some cases have larger flash holes and some are smaller - Whatever they do at the factory seems to be ok but when I took them all up to the larger size I had a whole series of problems. It wasn't limited to primers backing out either but that was one of the more universal problems.

[cwlongshot]

  Weak loads (starting loads) can sometimes cause the primers to back out a bit.  Increase the charge and see if they stay in place.

 I agree with above...

but did anyone notice that the origional question was posted almost NINE MONTHS AGO!!!

CW