brass with ejector marks

[amlevin]

The proper way to set up a full length die is to take exact measurements of a fired case, using one of the several tools designed for the job, and to set the die for a specific datum line to head dimension.

And this method works fine right up to the point where you've backed off the die for proper "headspace" measurement on the sized case but due to the taper, haven't sized the base of the case sufficiently to fit the tight chamber of your rifle.

Not too much of a problem when shooting brass from the same rifle but a bugger when moving brass "from one rifle to another".

This is where either a custom die, or having a rifle chambered to a dummy round comes in handy.

I've always felt that directions that come in ANY box of reloading dies are written "to address the lowest common denominator". That would of course be the totally new "beginner".

 

[BoydAllen]

That reminds me of when two friends, both experienced reloaders with factory chambers, each had a custom slow twist 6BR built for varmint shooting. I told them that they should send fired cases to Harrell's Precision for an affordable, but custom fit die that matched their chambers, but they shined me on and got what they thought looked much nicer, and because of that just had to be better, and then found that at the correct shoulder bump, that they did not get any sizing at the cases base. Then....they took my advice, and from that point on everything worked as it should. There are a couple of points to this story. The first is that if the die that you have does not size the base of your fired cases when set for the correct shoulder bump for your rifle, you will need another die. The situation cannot be remedied any other way. Edited later: (unless you polish out the back of the chamber so that it is big enough for the die to work) The second is that some people have had the mistaken idea that reducing all of the dimensions of a reamer to produce a so called match chamber is the best road to accuracy. While this can be useful at some points in the chamber it can be a bad idea, if carried too far in others. Personally, for a custom project, I prefer to buy a good die first, size some fired brass with it, making sure that it is actually sizing at the shoulder and near the head, and then order a chamber reamer for the desired clearance to those sized cases. I look for well used cases for this, since they have been work hardened so that they will produce the largest sized case that will come out of a particular die, due to the increased spring back.

 

[bigedp51]

The brass didn't flow into the ejector because of lube or oil in the chamber meaning additional bolt thrust. The brass flowed into the ejector due to high chamber pressure that exceeded the strength of the brass and extruded the brass into the ejector hole.

I could lube the cases of my 30-30 and shoot them all day long and the brass would not flow because the chamber pressure is only 38,000 cup or 42,000 psi and not high enough to cause the brass to flow.

Lubing a case or having oil in the chamber doubles the bolt thrust but does not increase chamber pressure unless the oil or lube is forced into the bore.

Just one of the reasons military chambers have longer headspace is because it reduces bolt thrust because the case stretches to meet the bolt face and acts like a shock absorber. This reduces the bolt thrust and the dwell time the base of the case is in contact with the bolt face.

The brass flowed into the ejector for the same reason the unsupported base of the case flows outward in the example below.

Military brass is made harder in the base to better withstand higher pressures caused by combat conditions like water in the chamber and bore. CatShooter in a post here measured the rockwell hardness of .223/5.56 cases with Lake City being the hardest and Remington being the softest. Lapua brass was the second hardest and if the OP had used Remington cases his brass flow into the ejector would have been more pronounced.

Just one of the many causes of the M16 jamming problem was soft brass and then mil-spec standards were set for all commercial contract military cartridges.

Below internal case capacity effects chamber pressure, the two charts below show .223/5.56 cases with the top chart being Lake City with the most internal capacity. Both cases have the same identical charge of H335 but the lower chart shows a case with 1.8 grains of H2O of less capacity and 6,000 psi higher chamber pressure.

Bottom line, if the brass flows into the ejector you have exceeded the structural strength of the brass and need to back off the load. And if brass flows into the ejector with Lake City or Lapua brass the pressure is higher than you think.


You could try soaking the brass in Viagra, but if the brass stays hard for over four hours you must call a gunsmith. :

 

[bigedp51]

This forum is filled with very smart and experienced shooters who know and UNDERSTAND what they are doing. BUT some people who do NOT understand what they are doing end up reading what is done HERE with MODERN bolt action rifles, and pass what is said here along. The problem is what they read here ends up in milsurp forums with rifles over 100 years old or in forums for lever action rifles that are not made as strong as a modern bolt action. These people even tell you its safe to leave any oils in the bore because what they have read in other forums.

I know a cartridge case could be lubed with a mid range load and the the bolt thrust would be no greater than a max load with a dry chamber. The problem with lubing case is stupid people doing this with the wrong rifle and allowing any lube or oil to get in the bore and raise chamber pressures to dangerous levels.

Bolt thrust is like walking around the block compared to running a 26 mile marathon, when you run you have 26 tons of force hitting your foot with each stride. I'm flat footed, I do not load my case to the max, I do not lube my cases and I know what age and gravity did to my feet.

Excessive bolt thrust can age your firearms prematurely and the first sign is increased headspace, the problem is getting the less knowledgeable shooters to understand this.

Right now at the castboolits forum a person by the screen name of mutigunner is handing out information. The problem with this information is mutigunner doesn't cast bullets or even have a reloading press. And what people read in forums, written by midgets sitting at their computers pretending to be giants can be hazardous to your health.

What I have said above is NOT meant to be an insult to the "EXPERIENCED" shooters who know what they are doing here. It is a warning directed at the inexperienced shooters reading second and third hand rumors in forums by people who do not know what they are talking about.

Know thy rifle................

 

[BoydAllen]

Personally, I never lube cases, even in situations where I am sure that I could easily get away with it. This is because I can get the same thing done with a dry case, and that leaves me with less to do. The only time that I have discussed oiling cases here was to report what someone does in a particular situation that cannot generate dangerous pressure. I completely agree about being careful what you try based on what you read on the internet. The best thing that you can do is to find yourself a couple of very experienced reloaders that do not know each other, and make sure that whatever you you try, checks out with both of them, and that they can give you a really good explanation of what you are about to try. Bottom line, we can do it all, without ever taking unnecessary risks, so why would you?

 

[Gary Manley]

I've been reading through several discussions re ejector marks.
I just thought I'd chime in another ejector issue that leaves identical marks to pressure.
That being a dirty ejector hole and spring.
I just purchased a new long-range rifle (brand is being withheld because I don't want to cause the manufacturer problems. I popped the firing pin assembly out and then tapped the retaining pin from the ejector until I could remove the pin and spring.
There were shavings from the drilling of the ejector hole in the bolt face, some small pieces in the spring coils also. I ran a small pick inside the hole then blew it out. Returned the spring and ejector and reinstalled the pin. Guess what? No more ejector marks!
I've seen ejectors have issues on AR platforms also. I have had to polish many in my 50 years of gun work.
An issue that can be easily overlooked and can cause temporary insanity.
That's it from me!

 

[J_idaho]

When fire forming you will see an increase in pressure on the first firing depending on how far the case has to expand to fit the chamber. Especially in heat. Do not move shoulder back until 3rd firing. And then only move it back .001”-.002” I believe it all depends on the size of the chamber. A max saami chamber plus a min saami case equals very high pressure spikes. And it destroys the life of your brass.