Raised Ring at Base of .223 case?

[jlow]

And "WHY" would someone use Lapua brass in a rifle that throws perfectly good brass away and makes you go look for it?

I for a fact use Lapua 223 brass in my AR-15 with an over max load and don’t have a problem like the OP has found. Go to Reply #30.

 

[bigedp51]

And "WHY" would someone use Lapua brass in a rifle that throws perfectly good brass away and makes you go look for it?

I for a fact use Lapua 223 brass in my AR-15 with an over max load and don’t have a problem like the OP has found. Go to Reply #30.

And I have a stock factory .223 Savage with a longer throat than either of my AR15 rifles.

Meaning the OP is the one having the problem with "HIS" rifle.

And your AR15 isn't the topic of this posting and also why load data varies.

And as a side note I would never brag about going over the rated pressure of any rifle.

And 95% of what I shoot is 5,000 psi "BELOW" the rated chamber pressure of the .223/5.56 and the brass lasts a long time and doesn't have ring around the collar.

 

[jlow]

I posted that data to support the fact that Lapua cases can take reasonably high pressure without expanding its base. That is not bragging but providing hard data to help trouble shoot the OP's problem. You should learn to recognize the difference.

Speaking of hard data, you have put out a ton of stuff but not NOT one single piece of data that actually support your notion that the metal in LC brass can take more pressure than that use by Lapua....

 

[bigedp51]

I posted that data to support the fact that Lapua cases can take reasonably high pressure without expanding its base. That is not bragging but providing hard data to help trouble shoot the OP's problem. You should learn to recognize the difference.

Speaking of hard data, you have put out a ton of stuff but not NOT one single piece of data that actually support your notion that the metal in LC brass can take more pressure than that use by Lapua....

Jlow, what does the statement below tell you??????

Strange that it showed up on these, but not my other brass. I have shot LC in the past without this issue.

Jlow

It isn't my "notion", milspec brass is made to higher standards than SAAMI cartridge cases, and is made to higher military standards. The M249 machine gun has a even larger diameter chamber and Lake City brass doesn't get a ring around its base.

The OP answered his own question, his Lake city brass doesn't have the same problem as the Lupua brass.

And if a few more people read the book below they would understand what I'm trying to get across. I'm not giving my opinion or a wild a$$ guess, I'm passing on published facts.

And my finger below is pointing at a "hard fact" brought out in Congressional investigations as to just one of the causes of jamming with the M16 rifle when it first came out.

The milspec brass was made harder to stop it from deforming and it is a published fact. If you think 5.56 brass is made to the same standards as commercial SAAMI .223 brass then you have a reading disability and don't understand the data I posted. Meaning what is yield strength in relation to brass hardness. :

 

[WindSurgeon]

Go back to my post above. You reference a reloading manual. Which one and does it give loads specifically for the AR-15 or just for the .223 Rem? If you are using .223 data not designed for the AR, then all bets are off. Many of us are giving you the answers you need and you are not listening.

You are treating a mil-spec chamber like a match chamber. You are running overpressure loads to hit some mythical node you have found. At the least, get yourself a carrier weight system, some new brass and start over carefully with your load development using data designed for the AR-15 platform.

Scott

I am using the AR15 Loading manual from Sierra. See attached. It is also on this website in the .223 section.

 

[jlow]

Ed,

I only wish you are right as it would quickly help the OP figure out his problem, but unfortunately there are holes big enough in your conclusion to drive a semi through...

So the OP “shot LC in the past without this issue” would be great evidence except:

• If we know that everything he used in those reloads were exactly the same.
• If the Lapua brass had exactly the same weight and internal dimensions as the LC.

But we the answer at least for the second point is a resounding NO. The fact is the difference in volume could also be responsible.

As for the notion that milspec brass is of a higher standard and that congressional investigation. You do realize that article only talks about 5.56 brass but NOTHING about the Lapua brass. So this whole notion that Lapua brass is different is not supported by any data you have shown.

 

[WindSurgeon]

Guys (and maybe gals, don't know), There's a lot of great ideas here. This is the purpose of this thread is to show a condition I could not find anywhere on-line so all could benefit. I really appreciate everything and will be pursuing all ideas to find a root cause and solution. The collaboration among shooters is tremendous! I don't want to rule out anything at this point, most of all my own mistakes and wrong assumptions loading for this rifle. Right now, I don't think there is wrong or right, just great thoughts and data to consider. Much appreciated!

 

[bigedp51]

As for the notion that milspec brass is of a higher standard and that congressional investigation. You do realize that article only talks about 5.56 brass but NOTHING about the Lapua brass. So this whole notion that Lapua brass is different is not supported by any data you have shown.

And you sectioned Lake City cases and Lapua cases and have a pressure test barrel and a Rockwell hardness tester to back up your "notions" ??????????????????

 

[jlow]

As for the notion that milspec brass is of a higher standard and that congressional investigation. You do realize that article only talks about 5.56 brass but NOTHING about the Lapua brass. So this whole notion that Lapua brass is different is not supported by any data you have shown.

And you sectioned Lake City cases and Lapua cases and have a pressure test barrel and a Rockwell hardness tester to back up your "notions" ??????????????????

My notion is like everyone’s notion coming into this discussion and that is there is no significant difference in the hardness of the LC and Lapua brass. That may or may not be correct, but since you are the one that says they are significantly different, it is up to you to come up with the evidence to prove it.

You cannot come into any discussion making claims with no proof and then challenge people who ask you for proof to come up with the goods – that is just twisted logic.

 

[bigedp51]

My notion is like everyone’s notion coming into this discussion and that is there is no significant difference in the hardness of the LC and Lapua brass. That may or may not be correct, but since you are the one that says they are significantly different, it is up to you to come up with the evidence to prove it.

You cannot come into any discussion making claims with no proof and then challenge people who ask you for proof to come up with the goods – that is just twisted logic.

The only thing "twisted" is your ability to look at what I posted and realize the material isn't my "notion".

The key words below from the photo are "harder brass" than SAAMI standards. :

The photo above is from an article on .223 vs 5.56 comparisons from Gun Digest 2013 by Patrick Sweeney. And jlow if you think you know more than Mr. Sweeney you should contact him and dazzle him with your brilliance and knowledge on the subject.

And the last time I looked Finland wasn't part of NATO and doesn't shoot our mouse gun caliber in 5.56. Meaning Lapua is making standard .223 cases and not milspec 5.56 cases.

So let me know if Lapua has a contract to produce 5.56 NATO ammunition for our military. :

 

[jlow]

Whatever you say bud... :

 

[bigedp51]

Whatever you say bud... :

Its amazing how the accurate information I supply has been praised by so many of the forum members here.

Thanks bigedp51! Good to hear of your experience – that is comforting.

Thanks bigpedp51 – that is interesting.

bigedp51 - Thanks – some very interesting data – thanks for posting.

This one is my favorite. ;D (and they have a internet spell checker you can download that works in forums if you have the "notion") :

Thanks bigedp51 – your frank input is much apparciated.

I'm sure the forum members here enjoyed our back and forth physiological warfare dissertation on half hard and full hard brass.

Have a nice day.

 

[jlow]

Thanks for posting my comments. It just goes to show that I am fair and always appreciate good input and information, but not bad ones when they show up.

You might think it is fun psychological warfare (BTW not physiological warfare – not really sure what that would be...) but this type of thing just makes you look bad. :-\

 

[bigedp51]

Thanks for posting my comments. It just goes to show that I am fair and always appreciate good input and information, but not bad ones when they show up.

You might think it is fun psychological warfare (BTW not physiological warfare – not really sure what that would be...) but this type of thing just makes you look bad. :-\

Dear jlow

It was physiological warfare, I'm better looking, smarter and far more humble than you are. :

The above statement is called humorous psychological warfare because your statements in this posting come under the heading of psychological egoism.

"Psychological egoism is the view that humans are always motivated by self-interest, even in what seem to be acts of altruism. It claims that, when people choose to help others, they do so ultimately because of the personal benefits that they themselves expect to obtain, directly or indirectly, from doing so. This is a descriptive rather than normative view, since it only makes claims about how things are, not how they ought to be. It is, however, related to several other normative forms of egoism, such as ethical egoism and rational egoism."

The above meaning you actually think you tested Lapua brass without any test equipment to backup your flawed testing methods.

 

[jlow]

Dude, you just don't know when to quit do you? Give it a rest and stop digging... Nobody is interested and you'll be talking to yourself from now on. Good luck.

 

[BoydAllen]

If I may, since we seem to be an argument taking place that is in need of some hard data, perhaps there is something short of a pressure gun, and materials testing laboratory that can she some light on the situation, a chronograph. If the same bullet, with the same seating depth, and the same weight of the same lot of the same powder, with primers from the same box, are loaded into the LC and Lapua cases, and shots fired over chronograph screens, would not the data that resulted tell us something about differences in pressure? Could it not be that the cases are a similar hardness, and it is the differences in pressure that they are subjected to, because of their differences in capacity that are the reason for their differences in expansion? Finally, what I am suggesting should be easily within the reach of the average reloader. Another thing to consider is that powders' charge to pressure curve is not linear beyond a given range, and if one is at the top end of that range and some factor takes pressure above that , a disproportionate effect will result.

 

[jlow]

Boyd, dissusing ideas using hard data is always a good idea. The problem here as I have pointed out more than a few times is the cases have known significant differences in volume. We know of course that cases with smaller internal volumes will give higher chamber pressure - this is why we always reommend shooters who change cases to one of smaller internal volume to reduce the charge and work out the load again. So going by the experiment you suggested, how do one determine if we see an expanded case head using the same bullet, powder and primer that this was causes by softer case or smaller volume?

 

[BoydAllen]

Obviously one does not...but I think that it would be useful to get some idea of size of the difference in velocity that is the result. The next step would be to load the LC brass to the same velocity, or perhaps a little higher, so see how those cases react. The reason that i say a little more is that with a larger volume, at the same pressure, the velocity will be greater, but it will take more powder. Example (exaggerated difference in capacity to make point) : .222 vs .223

 

[jlow]

I can tell you from firsthand experience that using LC cases results in lower pressure. I frequently use LC09 cases for fouling rounds and as an example in one run both sets of cases loaded with 24 grains of TAC, same bullets and primer the velocity was 2592fps for Lapua vs. 2528fps for LC, that is a 62fps difference.

I don’t think anyone should do as you suggest which is to “load the LC to the same velocity, or perhaps a little higher, so see how those cases react”. Remember when a case head expands like what the OP saw, you are getting excessive pressure and I don’t think anyone who values their fingers, eyes, or rifles should do this.

Backing up a little, remember that there are already at least two good potential reasons why the OP are seeing excessive pressure – loading cases with smaller volume with the same charge and possibly jamming. Now because someone else comes out with an unsubstantiated claim that this is because the Lapua cases are softer than LC cases and someone should risk life/limb/rifle to test this idea?

My suggestion is if someone thinks this case softness idea is real and they want to champion/proof it, test some cases with hardness tester and report back.

 

[effendude]

All of the points above are valid but... I sound like a broken record here but with an AR unless the gas port is blocked, the bolt may be unlocking before pressure is down to safe levels. The gas port's only regulation is its location and size. It takes as much gas as it can handle.

Testing over a chrono will show the differences in velocities but the inherent design of the rifle adds a huge variable to the experiment.

Scott