I am reloading for my .243. After resizing I notice a nice bright shiny ring on the base of the case. This is probably the 4th resizing of the brass. I keep my loads well below max. These were fired with 35 gr of 4064 and 90 gr nosler AB. My press is set to slightly cam over for head space. I size and trim each case. Question: Do I toss the brass and move on?
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Pressure ring on .243 brass,toss'em?
- Thread starter Sea Buck
- Start date
jwrowland77
New member
Take a paper clip and make a L at one end. Stick it in the case and check to see if there is a "valley" down where that ring is. Sounds like you might have incipient case head separation. In which case crush the neck and toss in recycle bin to sell later for scrap.
If you're getting an incipient separation pressure ring, your dies are improperly set up. Here's how to correct the problem.
Loosen the lock ring on your sizing die. Back off the die about a hald turn or a bit more.
Take a once fired case and blacken the neck and shoulder with a Sharpee pen or Magic Marker. Carefully lube the case so not to wipe out the blackened portion of the case.
Slowly size the case and note where the case is marked. Lower the sizing die a bit and try again. When the marks on the neck come up against the shoulder of the case, carefully clean off the lube and try it in the rifle. You should feel some slight resistance closing the bolt. Lower the sizing die just a hair more, lube and size the case and clean off the lube and try it in the rifle again. Should go easy this time but if not, lube, size after slightly lowering the die once more. Then tighten down the lock ring and try another once fired case just to be sure. You just want the case to entered the chamber with ease without setting the shoulder too far back.
In essence, what you have just down is set up your sizing die to do a custom fit of your brass for your rifle's chamber. I set up every one of my sizing dies by this method.
Paul B.
Loosen the lock ring on your sizing die. Back off the die about a hald turn or a bit more.
Take a once fired case and blacken the neck and shoulder with a Sharpee pen or Magic Marker. Carefully lube the case so not to wipe out the blackened portion of the case.
Slowly size the case and note where the case is marked. Lower the sizing die a bit and try again. When the marks on the neck come up against the shoulder of the case, carefully clean off the lube and try it in the rifle. You should feel some slight resistance closing the bolt. Lower the sizing die just a hair more, lube and size the case and clean off the lube and try it in the rifle again. Should go easy this time but if not, lube, size after slightly lowering the die once more. Then tighten down the lock ring and try another once fired case just to be sure. You just want the case to entered the chamber with ease without setting the shoulder too far back.
In essence, what you have just down is set up your sizing die to do a custom fit of your brass for your rifle's chamber. I set up every one of my sizing dies by this method.
Paul B.
FrankenMauser
New member
Or, he could just have a chamber with a wide butt.If you're getting an incipient separation pressure ring, your dies are improperly set up. Here's how to correct the problem.
I have seen that situation, before.
The chamber was more oversized near the case head than the neck and shoulder. As such, you had to "overwork" the brass up front, in order to get the base sized far enough to be useful. (A custom die or barrel set-back and rechamber was too expense, and not justifiable.)
The result was reduced brass life, but I/we still had the ability to use that ammunition in more than one rifle.
The cases all had very obvious 'pressure rings', but typically lasted for 6-8 firings before being work-hardened or showing evidence of imminent separation.
for decades the go to powder for the .243 was 4350. Ed matunis referred to it as the "only correct powder". a 100 grain bullet can reach about 3,000 fps, and in my testing it was the absolute best accuracy compared to any other load. the load fills the case to a few mm. It is not only highly accurate in 100, I also had great results with nosler 60 gr (iirc) HP. Yes, it uses a bit more powder, iirc over 40 grains, but the sierra btsp at 45 (iirc) chronographed at 3k, gave accuracy about MOA at every shooting session, and never showed pressure signs.
You'll obviously get other opinions, but "camming over" is unnecessary and IMO can eventually compromise the bearings of the machine, or cause other problems. As long as your die body is fully in contact with the shell holder, no matter how much harder you press on it, it's not going to change anything in the eventual sizing. Of course, it would take a machinist with a micrometer set to confirm that absolutely. I'd just stop doing it.
I think that brass is too cheap to take any risks. If you are pressing your loads to the point that you got a genuine pressure ring, that brass will be compromised when you continue to use identical loads. I have just recently begun to reload again, after several years of not shooting at all due to health issues. I dumped hundreds of rounds of rifle brass because I could not positively identify which rifle I had used them in, how many loadings, etc. I will also be dumping the brass from all loaded ammo as I fire it. Yes, I have hundreds of dollars in future costs to restore my full complement of ammo.
IMO:
dump the brass. Start with new brass. Look at another powder. use a slow powder such as 4350 or another in that same category, stick ball, whatever. It is traditionally held that most powders function best when the case is almost full; it allows for more consistent ignition. This does not mean that compressed loads aren't efficient, the consistent ignition is still there. Pressures that are position sensitive will be, as stated, position sensitive, and may cause erratic ignition if the case has a lot of air space.
You failed to mention what rifle you use, full length vs neck only dies, and other things that will have bearing. A bolt rifle neck sized is going to perform very differently from a semi rifle that is full length resized every time to allow easy chambering,
You'll obviously get other opinions, but "camming over" is unnecessary and IMO can eventually compromise the bearings of the machine, or cause other problems. As long as your die body is fully in contact with the shell holder, no matter how much harder you press on it, it's not going to change anything in the eventual sizing. Of course, it would take a machinist with a micrometer set to confirm that absolutely. I'd just stop doing it.
I think that brass is too cheap to take any risks. If you are pressing your loads to the point that you got a genuine pressure ring, that brass will be compromised when you continue to use identical loads. I have just recently begun to reload again, after several years of not shooting at all due to health issues. I dumped hundreds of rounds of rifle brass because I could not positively identify which rifle I had used them in, how many loadings, etc. I will also be dumping the brass from all loaded ammo as I fire it. Yes, I have hundreds of dollars in future costs to restore my full complement of ammo.
IMO:
dump the brass. Start with new brass. Look at another powder. use a slow powder such as 4350 or another in that same category, stick ball, whatever. It is traditionally held that most powders function best when the case is almost full; it allows for more consistent ignition. This does not mean that compressed loads aren't efficient, the consistent ignition is still there. Pressures that are position sensitive will be, as stated, position sensitive, and may cause erratic ignition if the case has a lot of air space.
You failed to mention what rifle you use, full length vs neck only dies, and other things that will have bearing. A bolt rifle neck sized is going to perform very differently from a semi rifle that is full length resized every time to allow easy chambering,
I've loaded mine waaaaay more than 4 times with Speer 90 using 40.5 of IMR4350(mid range load) and FL resizing every time.
If you're cases are about to separate after only 4 loads, something horrible is going on. Possibly with your rifle. More likely that your just seeing the result of resizing. Tends to leave a mark. Check 'em with the bent paper clip just to be sure though.
If you're cases are about to separate after only 4 loads, something horrible is going on. Possibly with your rifle. More likely that your just seeing the result of resizing. Tends to leave a mark. Check 'em with the bent paper clip just to be sure though.
SeaBuck, how far down on the case is this ring? And what make of brass is it?
If it is almost all the way down at the case head you probably have nothing to worry about and what you are seeing could be an artifact of the sizing die not making contact with the case all the way to the case head. I have seen this for my 308 when I was using a Lee die. Nothing to worry about since it has to do with cosmetics as opposed to integrity of the case.
If the ring is further up on the body it is more likely to be indicative of incipient case-head separation.
Either which way, check using the paperclip method.
If you do have incipient case-head separation, the main thing to make sure is that you are not bumping back your shoulders too far when resizing. If your case-head to datum line for a fired case is 1.622 (to pick a random number) and you bump the shoulder back too much (say 1.600 in this example), you have a higher chance of experiencing case head separation no matter how mild the loads since there is too much room for expansion when the case is fired. Higher pressures will work the case harder but as long as you keep the resized case to about 5 thousands of the fired head-to-datum measure you can work most quality brass pretty hard without any separation issues.
If it is almost all the way down at the case head you probably have nothing to worry about and what you are seeing could be an artifact of the sizing die not making contact with the case all the way to the case head. I have seen this for my 308 when I was using a Lee die. Nothing to worry about since it has to do with cosmetics as opposed to integrity of the case.
If the ring is further up on the body it is more likely to be indicative of incipient case-head separation.
Either which way, check using the paperclip method.
If you do have incipient case-head separation, the main thing to make sure is that you are not bumping back your shoulders too far when resizing. If your case-head to datum line for a fired case is 1.622 (to pick a random number) and you bump the shoulder back too much (say 1.600 in this example), you have a higher chance of experiencing case head separation no matter how mild the loads since there is too much room for expansion when the case is fired. Higher pressures will work the case harder but as long as you keep the resized case to about 5 thousands of the fired head-to-datum measure you can work most quality brass pretty hard without any separation issues.
I'm with Paul B. You can take the worst case with the stretch condition and try the wire feeler on the inside of the case. Cut open or grind the area open to inspect the condition. If it is much thinner than the surrounding area toss those that are alike. Then adjust the die as Paul B. mention and you should not have any more issues for a wile. It is not un unusual to see those stretch marks when slightly over sizing the cases. You should get much longer live out your cases using Paul's process.
Often the die will leave a ring just ahead of the rim, where the interior of the die stops squeezing down the brass. That is normal, and not a cause for alarm. Always a good idea to do the bent paperclip test to verify though. In my experience the bright ring associated with case stretching normally happens a bit further up the case, above where the thick web area transitions into the thinner sidewall of the case. Google photos of case head separation, compare what you're seeing with the photos - in many photos you can also see the ring left by the sizing die further down on the case.
Snyper said:A bright ring on the outside of the case is perfectly normal.
If you can't feel it on the inside there's nothing wrong.
^^^This!^^^
That said a picture of these cases would be helpful.
Question: Do I toss the brass and move on?
I do not know what you should do with your cases, I do suggest you develop a way/means to measure the length of the case from the shoulder to the case head. Meaning? Before you toss the cases practice measuring the length of the case from the shoulder to the head of the case. Then start measuring case length from the shoulder to the case head before sizing and again after sizing, the difference in length between the two cases will indicate the amount of sizing.
Then there are different schools/thoughts. I want to reduce case travel meaning I do not mindlessly place a case into the shell holder with the die screwed down to below contact with the shell holder 'unless' I have one of those fancy chambers.
F. Guffey