Case - my 1st rupture/seperation

dcloco

Reloading for my 270 Winchester and experienced my first case failure.

Primer is slightly flattened, but the case is definitely cracked, almost 1/2 the diamter, about a quarter inch up from the base.

I dumped all fifty brass.

Going by the books, this load is 3/4 of a grain under maximum. But, I changed one thing, my OAL is longer, I am seating 0.020" off the lands.

n/a

I doubt the seating depth had anything to do with it. .02 off the lands is WAY off the lands...plenty of bullet jump. I seat most of my bullets at .005 off the lands. You might have a head spacing problem. I'd definitely check it out. You may be setting the shoulder too far back during sizing, as well. You should definitely take this rifle to a gunsmith and have him check out your chamber deminsions with headspace guages. If that ends up not being the problem, I would lay money on the fact that you are resizing the brass incorrectly. Someone with more knowlege than me will probably chime in here though. good luck.

dcloco

I agree...0.020 is way off the lands.

This is a commercial, sporter rifle.

I am using 150 gr bullets over H4895 (42.0 grains).

Of note, the cannelure on the bullet, is nearly 1/4 inch above the mouth of the neck.

How should I set up my dies? I am using RCBS.

PJ

How many times have you reloaded this brass?
Pete

dcloco

This was the second time.

I set the die up, per RCBS instructions. Touch the shell holder and another 1/8 to 1/4. In this case, I went 1/4 turn more.

JustC

Are you FL sizing? if so, how many times? FL kills cases almost as quick as excess headspace[:0] Set your dies to "Partial Full Length" size the case. This sizes maybe 3/4 of the neck and only compresses the expansion ring at the case-head while pulling the shouler fwd for a good tight fit and far less case stretch.

NK sizing makes cases last longest, but isn't always feasable depending on purpose.

Casehead seperations and flat primers in only a few firings says excess headspace, if that is the case, send it off for a barrel set-back.

JustC

I see you replied while I was typing,..so it was only a few firings and you set those shoulders wayyyyyy back by your set-up description. Screw the die in until it is about a nickels thickness away from the shell-holder,.....then size a case. Take your headspace guage and check the datum line on the shoulder,...then start to screw the die in 1/8 tunr at a time until the shoulder datum line comes fwd by .002-.003". If you don't have a tool, you can chamber the fired round each time until you feel resistance closing the bolt. This case is now PFL sized. It WILL last longer and it will most likely shoot better.

AND, STILL, I would have that chamber inspected. Even that few firings says you have excess headspace without the FL sizing included.

dcloco

JustC,
Thanks.

I have been reading since I got home.

I know that I am near the max with this bullet/powder/and OAL combination.

I will get the chamber checked.

I do not own a set of gauges.....will have to order a set. Nothing like being in the middle of BFE....USPS and UPS are my friends!

Of note on neck sizing versus full length sizing, I have been doing extensive experiments with my 223. To date, neck sizing has not produced a group better than full length sizing. I posted about my first under 1" group at 300 yards. 60 gr Vmax, H4198, and full length resized. To date, I have shot 300 rounds, in groups of 10, with two different bullets....150 cases neck sized, 150 cases FL...everytime, the FL has beat the neck sized. Has been very close a couple of times, but overall, FL has been the way to go.

I believe that I can begin to get a reference, by using a 30 caliber Stoney Point OAL insert and measure the shoulder with that.

JustC

have you run the load ladder sperately with nk sized cases?? if so, you may find an accuracy load that is a bit higher in charge due to the greater internal volume of a NK sized case vs a FL sized. Try the PFL method and see if you get the accuracy but with better case life.

Check how far the datum line is on a new case and a fired case. That may tell you how large the chamber is. But, if the chamber is correct and it is just overworking of the brass,..maybe try turning the die out just a tad at a time to size the case down, but not as much. I would think crapping out brass necks in so short a time has to point at something wrong somewhere, but I can't tell for sure.

Maybe look at annealing the necks each time and keep doing it the way you are now,..that may double or triple your case life and you can still run them as is.

dcloco

Case failed at the bottom - about a 1/4" up from the case head.

I loaded 100 rounds, at the same time, using the same powder charge, scale, etc, etc.

I checked the first 50 cases that I fired, slightly flattened primers, but no failed cases.

The second 50 cases, were fired yesterday.

Not sure yet...I will keep trudging! Thanks for the help everybody!

n/a

quote:Originally posted by dcloco
Case failed at the bottom - about a 1/4" up from the case head.

I loaded 100 rounds, at the same time, using the same powder charge, scale, etc, etc.

I checked the first 50 cases that I fired, slightly flattened primers, but no failed cases.

The second 50 cases, were fired yesterday.

Not sure yet...I will keep trudging! Thanks for the help everybody!


I would venture to say that it's a headspacing problem. Have the rifle checked out by a gunsmith and if that's not the problem, your dies are set up wrong...you are pushing the shoulders back too far. The flattened primers can be the result of a headspacing problem as well. I would not shoot the rifle again until you find out what the problem is. If you have any ammo left, it might be worth pulling the bullets and primers and starting over after you reset your dies. Good luck!

dcloco

No loaded ammo left.

Will get the rifle checked. That will be a couple of months, no local gunsmith.

n/a

quote:Originally posted by dcloco
No loaded ammo left.

Will get the rifle checked. That will be a couple of months, no local gunsmith.


Where are you at...someone here might be able to direct you to a local gunsmith...

Highball

If you have access to a Micrometer...and an unfired round...you can do a rough check of headspace.

Remove the firing pin first..you want to be able to 'feel' what is happening.

Cut a slightly-smaller-then case-head size disc out of paper..(mike it..you want paper .003 or .004) or shim stock is better...place a small dab of grease on the case head and place disc there.

chamber the round and CAREFULLY close the bolt...you are feeling for resistance. Slamming the bolt closed will just crush the case shoulder.
Try and determine exactly how much thickness is required so bolt will just start to close.
I cannot locate the exact min/Max headspace at the moment...but I prefer a minimum amount...a couple thou.

Headspace is not as serious a problem as some make it out to be...ASSUMING YOU RELOAD...and set the dies up properly.
Blacken the case with a marker..and see how far down the case the black is rubbed off. Do NOT allow the shoulder to touch..it takes lots of rounds to require bumping the shoulder back.(Clean the die well afterwards..)

I believe you are setting the die to far down...1/4 turn from touching is a bunch..imho.

Am curious about one thing. You mentioned that your OAL is longer..(then the book, I assume)..yet you say you are .020 off lands. Is there the SLIGHTEST possibility you are actually touching the lands...? This CAN cause severe pressure spikes...

nononsense

dcloco,

The headspace dimemsions for the .270 Win. are:

270 Winchester

Go = 2.049"

No-Go = 2.055"

Field = 2.058"

As long as everyone else is having a run at this, I'll join in also.

Without being able to measure your cases or work with your reloading set up, my guess is that what you've done is set the shoulder back and thus created the circumstances that you describe. By moving the shoulder back, you have moved the datum line that the case headspaces on, back as well. So the chamber probably isn't out of spec but your cases most likely were. All of your description seems to match this idea.

Don't take this wrong. Re-read your loading manuals or check with a couple of online resources to get the process of setting up your dies firmly in your in mind. I've never read that particular method that you described above without the admonishment of checking headspace and hindsight indicates that the +1/4 turn is tad too much as far as my guess goes. The +1/4 turn is the equivalent of nearly 0.018" which is a significant amount if touching the die to the shellholder achieved the correct headspace in the first place.

Even though H4895 is listed as a potential powder, in my opinion it is too fast to use in the .270 Win. case unless it is with the very lightest of bullets. With your 150 gr. bullets seated out, you essentially have only about 75% of the case filled with powder and that's at the upper end of the recommended loads. Better performance can be achieved by using something in the Re-19, H-4350 or V V N-160 because those powders will fill the case nearly full and give an appropriate pressure with consistancy.

Please let us know how this progresses!

Best.

Highball

Thats another point...150 .Gr bullet, seated out 1/4 inch from cannelure..sounds like its seated pretty far out....adding suspicion that it is engraved into the lands.... Be interesting to get a follow-up.

dcloco

Thanks everybody.

I have triple checked the OAL with this bullet on at different times.

On the second check, I blackened the bullet with a sharpie and chamber the round at the max OAL. Just touching the lands was the result.

To make sure of this result, I used another bullet, marked with sharpie, but set the OAL 0.002 less than previous - no marks on the bullet.

I will check my headspace as indicated.

I will also double check setting up this set of dies.

dljacko

I Have read your comments and also feel that there is a headspace problem. If you are using standard RCBS or similar FL dies I would suggest that you only size enough to chamber a cartridge in your rifle. The instructions are there to ensure that a loaded cartridge will fit every rifle and there could be up to .005" difference between minimum and maximum tolerance there. You are only reloading for your particular rifle so you only need to resize enough for that rifle. Remember the less expansion and contraction of brass will result in it lasting longer.
I would cut some of the others in half lengthwise to see if there is any chance of head separation there. Just rub one half on a fine file until the burr from the cut is gone and you will easily be able to see.
Regards.

dcloco

dljacko - thanks for the info.

That was the first item I did - cut a case, above where the case head failure would be, with a tubing cutter.

No seperation present.

I believe this is a plain and simple oversizing problem.

Check this topic that I started as well...

http://forums.gunbroker.com/topic.asp?TOPIC_ID=204051

bgjohn

Wrong, wrong, wrong! Headspace problem my BUTT! That's all you guys can think of. Who has headspace guages in every caliber they own? Nobody has suggested that the case LENGTH might be too long. If too long the bullet pinches the case at the mouth and can cause a seperation. See a picture of this situation in the Hornady Handbook of cartridge reloading, 3rd edition page 15. The only time I have ever blown a case this was the situation. The caliber was 22 Hornet. I had one TC barrel that would blow the case and another where the same ammo would work just fine.

Anyway check your case length!
JM

dcloco

Actually, the cause was/is oversizing the brass.

Improperly adjusted the sizing die (followed the directions!!!)...

The case length is perfect.