Head separation on my brass

[montana west]

new incase lenght mm are easer to work with and the military uses mm.
example 308 win case 51mm 284 win 56mm- 6mm remington 57 and257 roberts 57
30/06 63mm 270- 280 64mm 7mm mag 264-338- 358 norma and 304 norma 416 taylor 63mm
300 win 66mm 375 hAH 8mmremington mag and 416 remington 72mm 63mm=2.5"

 

[Slibey]

Strange on once fired cases, had a separation like that on my 7mag, but they had been reloaded seaveral times. Started using a paper clip straightened out with a 180 1/8 bend on one end to check inside case wall, found some with shallow indented rings, tossed those to many full length sizing

 

[montana west]

slibey I too did that but i used a bycicle spoke cut it to 6 "or 150mm amdit wotj tje rpimd jead with a 90 bend you could feel the weak spots/but now with the 280 rem cases I do not have that problem. extra mm in case length worked for me but on a mag case you have a belt that controls the head space. in my case the chamber was a bit long i suppose for the 35" sholder.

 

[338 dude]

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

I agree but would like to add he has checked with gauges his chambers proper which leads right back to the factory ammo being too small which is still a headspace or length problem

 

[CatShooter]

I agree but would like to add he has checked with gauges his chambers proper which leads right back to the factory ammo being too small which is still a headspace or length problem

ALL factory ammo or cases are too short - it is the nature of ammo and chambers. You can have 0.014" of space between the case head and bolt face, and everything is in "SAAMI spec". And everytime you "bump" the shoulders with a FL die, you make things worse.

None of this is a problem if case length is properly managed.

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This is a post I did a few weeks ago on another forum, and it is relevant here because it is about excess headspace - a full 1/10" of excess headspace.

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I have always loved the .220 Swift, and have continuously owned one (or more) since the early 60's.

Back in the end of summer, 2013, I sold my last .220 Swift (with it's brass), in anticipation of getting my new, special order .220 Swift.

In March, 2014, I picked up a new Rem 40XB stainless single shot, chambered for .220 Swift.
It had been on order for 14 months, and I had a new 2 ounce Jewell trigger waiting for it.

I was in Groundhog shooter's Heaven... or so I thought!!

It was right after the Sandy Hook school shooting in Connecticut in Dec 2013.
Obama promised massive gun controls, everybody was buying up everything in sight... and no .220 Swift brass, even fired brass, could be found ANYWHERE.

I was chatting on a varmint shooting forum, and bemoaning the lack of .220 Swift brass. A very nice guy offered me 200 pieces of brand new Norma brass for free + postage. It doesn't get any better than that!!

The only catch was that he got them at a tag sale and the original owner tried to form the cases for the .220 Wilson Arrow (a popular wildcat in the 40's and 50's).
He did a very bad job. The cases were, for all practical purposes, useless.

But in desperation, I eagerly snapped them up and sent him $10.

Two weeks later, I was the proud (?) owner of the ugliest .220 Swift cases I ever saw.

Inspection of the cases showed the following.

1 - The cases had the worst hydraulic dents I had ever seen.

2 - Since the shoulders had been flared for the .220 Wilson Arrow, the cases wouldn't chamber and the bolt couldn't close on my rifle. (but that turned out to be an advantage).

3 - The biggest problem was that the shoulders had been pushed back so far that the cases had an average 0.100"+ of headspace (the shoulders had been pushed back a 1/10th of an inch).

The good part...

4 - They DID say "NORMA .220 SWIFT" on the case head.

The solution...

1 - I bought a used RCBS FL .220 Swift die on eBay for $10 (with free shipping ).

2 - While waiting for the die, I annealed the necks and shoulders, and then polished them in a vibratory polisher with corncob and Dillon polish for ~12 hours.

3 - Then I tested the case heads for hardness - it was not really necessary, but I have the gauge, so I did it - the cases were fine (they averaged 91 Brinell - very hard).

4 - When the die arrived, I slowly ran the cases into the die, turning the die down in small steps, while test chambering the cases in "trial & error" until I could close the bolt on an empty case with a lot of force. (When fired, I wanted the forward case movement to be as small as possible).

5 - I loaded the cases with stepped loads of 4064 and an assortment of 55gr bullets, seated to touch + 10 thou, so I could use fireforming to gather loading data at the same time..

When firing, I first rolled the cases over a pad soaked with a light gun oil (G-96) so they were wet with oil, and then fired the cases.

All the cases formed perfectly - none stretched at all. The reloaded cases are perfect.

What this shows is that cases can take a beating and still be fine - so don't worry about blowing out oil/hydraulic dents - they blow out to make perfect cases.

The biggest mistake handloaders make is using a full length die to bump their case shoulders, which causes case stretch - this is a case killer which leads to head separation, that cannot be corrected.

 

[Ekupp]

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

Did you ever determine if the etched rings on your brass were purely from excessive headspace or if there was engraving from an irregularity in your chamber? I am sorting out a similar issue.

 

[26Reload]

Well...id say the 280ai is etching on metal in chamber...
The 308....hot loads....
I've had 2 boxes of 65284 that couldn't handle the previous load I was shooting in original box of brass...most of that brass was loaded 9x.....the 2 boxes gone in 3 or 4 loads.....same head separation line...about same place on brass..
I watch very carefully with a 'pick' to the crevasse inside the brass..if it feels rounded..i shoot once more..it if sticks it gets tossed.....

 

[Unoboats]

Did you ever determine if the etched rings on your brass were purely from excessive headspace or if there was engraving from an irregularity in your chamber? I am sorting out a similar issue.

It was chatter marks from the reamer. Took barrel off and saved it, but rebarrelled to a 284 with a hart # 3 contour bbl

 

[Fedwell]

I have had some Head seperation with my 25-06 AI. The only New Brass I could find was some Over-priced Norma for Fire forming so i added a few once fired Hornaday to the mix. While working up a Ladder with HH 75 Bullets I got at or Near MAX Pressure. I havent seen any signs of seperation with the Norma brass while a few of the Hornaday Brass have failed? I'M kinda new at this do I have a head space Problem or is it just the Brass?
Thanks for any and all input.
Fed-Well

 

[ButterBean]

I have had some Head seperation with my 25-06 AI. The only New Brass I could find was some Over-priced Norma for Fire forming so i added a few once fired Hornaday to the mix. While working up a Ladder with HH 75 Bullets I got at or Near MAX Pressure. I havent seen any signs of seperation with the Norma brass while a few of the Hornaday Brass have failed? I'M kinda new at this do I have a head space Problem or is it just the Brass?
Thanks for any and all input.
Fed-Well

It's tha Brass

 

[Fedwell]

It's tha Brass

Thanks Bean, Hope you are having a good weekend.

Fed-Well

 

[montana west]

for sure the head space is a little long--easy to fix fire form yor brass - neck it up to .308 or 30 cal. set you resizing die up a half turn so it does not complete.y re size the sholder. when you fire the case with the false sholder it will completely fit your chamber perfectly; this is not always a bad thing and there are some gains for a long chamber like increased velocity with lower pressure. this will put the 280AI right up there with the 7mm rem mag.. of course you will use from 1 to 2 grains more powder like r-22 h4831 imr 7828 and h- 1000 . I have a 35 gibbs with this problem and for sure once I made the adjustments like going to ..375 the fire forming I have no more case seperations and it is very accurate and I push the heck out too the 358 norma mag. IN my case I use 280 brass because it is 64 mm long. but you just will have a case nedk about 1mm shorter and again you will never have to trim your cases from fireing growth. good luck

 

[spladi]

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.

View attachment 181224

FWIW.........masking tape is about .003" thick

 

[Ken61]

Have you checked the headspace on the rifles?