Head separation on my brass

[tnek13]

The conundrum is that the problem happens with factory ammo and not the component reloads. I would have thought headspace or a rough or dirty chamber, however, that would have affected all the brass. The next problem is that it is happening with two different rifles both of which you own, however, it is not happening with the component brass so the likely hood that you may be doing something wrong (cleaning, lubrication, etc.) is nill. So as observed above, something is amiss with the Hornady loaded ammo. If you have any left, I would call Hornady back and see if you can send it to them so they can check it out. They may not find anything wrong, but they might be nice enough to replace it.

 

[Almondgrower]

Unoboats: let me educate you on how a case head separation happens. (what conditions must exist)
it takes 30,000 PSI to stretch brass
it takes 0.010" to 0.011" excessive headspace to start showing signs of excessive head space.(that ring around the outside of the brass) if you look inside you can see ring more pronounced.
It takes 0.012" or more to separate case heads on brass
IF you had only bumped the shoulders 0.005" case head separation would never happen. Atleast I have never seen it with only 0.005" of excessive headspace in my 19 years of being a gunsmith.
Something in this whole mix is very false. If it is brittle brass as some have stated with Hornady brass then it is something I have never seen with Hornady.. R-P brass very much so.
here is how I would check how much excessive headspace you have. its easy and cheap to do.
first take a resized piece of brass for each of the guns you want to check headspace in, put in a primer. go outside, load the primed case in the chamber and point at the ground and pull the trigger. then extract/eject the case and measure OAL of the case. then measure from the case mouth to include the protruding primer. then subtract the two, that is your excessive head space. you should find it much more than you believe it should be.

I like that .......I have put a spent primer in brass and left it high and then chamber it , then measure , my neighbors get a little testy firing primers off in the back yard and it saves a trip to my shop/range but I'm going to try this too !

 

[Dean2]

Unoboats: let me educate you on how a case head separation happens. (what conditions must exist)
it takes 30,000 PSI to stretch brass
it takes 0.010" to 0.011" excessive headspace to start showing signs of excessive head space.(that ring around the outside of the brass) if you look inside you can see ring more pronounced.
It takes 0.012" or more to separate case heads on brass
IF you had only bumped the shoulders 0.005" case head separation would never happen. Atleast I have never seen it with only 0.005" of excessive headspace in my 19 years of being a gunsmith.
Something in this whole mix is very false. If it is brittle brass as some have stated with Hornady brass then it is something I have never seen with Hornady.. R-P brass very much so.
here is how I would check how much excessive headspace you have. its easy and cheap to do.
first take a resized piece of brass for each of the guns you want to check headspace in, put in a primer. go outside, load the primed case in the chamber and point at the ground and pull the trigger. then extract/eject the case and measure OAL of the case. then measure from the case mouth to include the protruding primer. then subtract the two, that is your excessive head space. you should find it much more than you believe it should be.

That is a highly unreliable way to measure head space. There are a raft of accurate and easy to do ways to measure it, primer back out is not one of them. On top of which you are recommending using a resized piece of brass so if the OP is over sizing his brass that will contribute to a false reading too.

Go, no-go, and a field field gauge set is the best method. The OP has already posted that the bolt won't close on a no-go gauge so he does not have excess head space. The ring is forming on the first firing of factory Hornady ammo, so clearly the issue is the ammo/brass. In the absence of having the proper gauges, the next closest approximation of head space, it will be out by the brass shrinkage factor post firing, is measuring a factory round from the base to the neck Datum line, before and after firing to see how much the neck has moved forward and OAL has increased.

 

[CatShooter]

If you have head separations, then you have headspace problems - headspace is the ONLY cause of head separations.

 

[Dean2]

If you have head separations, then you have headspace problems - headspace is the ONLY cause of head separations.

You are only partially correct, it is OFTEN the cause, even most often. Head space issue can be caused by the rifle having too much HS, but undersized factory brass, over sizing brass when reloading can also be the cause of excessive head space. Far more rare but I have seen it a few times, defective brass will cause separation issues too. It is usually from the brass being drawn too thin during forming or brass being made too brittle or too soft.

 

[IllinoisBurt]

The conundrum is that the problem happens with factory ammo and not the component reloads

My reading of the description was the ammunition is all reloads on their 3rd loading. The difference is some was bought as new virgin brass versus some was loaded ammo which he shot then reloaded twice. So I imagine Hornady isn't going to do too much to replace his now 3-times fired brass since the original ammo fired normally without separation.

 

[Mram10us]

I am a little confused on the 280ai. Is it the old school way, where you use the saami go gauge as the ai no go, or is it the saami 280 ai?

 

[CatShooter]

You are only partially correct, it is OFTEN the cause, even most often. Head space issue can be caused by the rifle having too much HS, but undersized factory brass, over sizing brass when reloading can also be the cause of excessive head space. Far more rare but I have seen it a few times, defective brass will cause separation issues too. It is usually from the brass being drawn too thin during forming or brass being made too brittle or too soft.

Head space is the space between the bolt face and the case head... no matter how it gets there.

When the case is fired the first time, and if it has oil on it, it will slip back and fill the chamber without stretching.

If it (and the chamber walls are dry) the case will stretch in front of the web.

From this point on, the loader is the person who adds headspace by bad loading practices,, and each time the case is fired, it will stretch.

If you are trimming more than once (the first time you trimmed), then the case is stretching, and on the way to a head separation.

 

[Unoboats]

Kimber 280 ai has been sent back to Kimber for examination of the chamber. I took a small piece burgundy scotchbrite pad and polished the chamber then lit the chamber up with light to reveal a etched ring in the chamber which looks to be at the same area of the marks on the brass. I loaded some new Nosler custom brass and it did the same to it. As for the 308 it seems to be a separate issue of definite excessive head space.i need to contact Hornady and let them know my findings as this is not there problem at least with the 280 AI

 

[Unoboats]

Head space is the space between the bolt face and the case head... no matter how it gets there.

When the case is fired the first time, and if it has oil on it, it will slip back and fill the chamber without stretching.

If it (and the chamber walls are dry) the case will stretch in front of the web.

From this point on, the loader is the person who adds headspace by bad loading practices,, and each time the case is fired, it will stretch.

If you are trimming more than once (the first time you trimmed), then the case is stretching, and on the way to a head separation.

That makes sense due to having to trim every time I load these 308's. I must have bumped the should back way too much. But not experiencing this on all the other rounds I load but the 308 dies are old Hornadys. The only Hornady set of dies I own. I imagine I am setting the sizing die wrong. I am now using a Dillon 550 press vs my old RCBS Rockchucker. I feel I need to revisit my loading practices. Thanks for all the feed back as it has lead in the direction of the actual issues.
sending back the Kimber and then me botching up my 308 loads.

 

[Almondgrower]

After so many posts on different threads I have read in the last few days , I can't remember if you have a Hornady headspace comparator (Assuming defective brass is ruled out ) that will be helpful to set up dies . Use a fired case to adjust dies every time you set up a sizer die to get just the correct shoulder bump . For me, I like to use my single stage press to do load work up , then use progressive for pistol or varmint/plinking rifle loads , hunting and competition rifles are all loaded on a single stage so powder charges can be as close to perfect as possible . Best of luck !

 

[Unoboats]

Hornady comparator

 

[montana west]

I had this problem with mt 35 gibbs wildcat. my neighbor a designer of supressors and cartridge engineer told me to go to 280 remington brass instead of the 35 whelen brass of which the sholder on the 280 was a bit longer as the 280 case is 64 mm instead of 63 mm and my problem was solved.. I am not sure but i believe the chamber is a tad too long but this issue can be solved and you will gain 25 to 39 fps over the original design.

 

[Mram10us]

I had this problem with mt 35 gibbs wildcat. my neighbor a designer of supressors and cartridge engineer told me to go to 280 remington brass instead of the 35 whelen brass of which the sholder on the 280 was a bit longer as the 280 case is 64 mm instead of 63 mm and my problem was solved.. I am not sure but i believe the chamber is a tad too long but this issue can be solved and you will gain 25 to 39 fps over the original design.

I've never known a man from Montana that measured in millimeters