Odd circular marks on resized cases

[jambrdly]

Hello:

I was resizing some 30-30 cases today and several of them came out of the die with an odd circular mark on the shoulder. Anyone ever see this kind of thing before?

If I figured the attach function out, there should be a picture here.

Thanks in advance

JCB

[Tuzo]

Inspect the inside of your resizing die. Seems as if a circular piece of loose brass (maybe from a trimming operation) became stuck in the die.

On the other hand, this may be a insidiously crude form of "macrostamping" proposed by gun control advocates.

[William T. Watts]

The cases were pressure rounds using a copper pellet (crusher method), Remington still uses this method.. I should ask if those cases are R-P cases and do you know where you picked them up? My guess you purchased them off some website, check your unsized cases prior to sizing and you may find more! William

[Kimber84]

Only time I've ever seen that was on fired brass (2 pieces). I ended up finding a sliver of copper or brass from a previously fired round stuck on the chamber wall that was causing it. Never had that happen from sizing though, guessing it might possibly be the same thing though??

[F. Guffey]

If the case was being imprinted in the die there should be a skid mark, meaning William T. Watts is correct.

If on the outside there is a chance there is a problem in the chamber load one of the imprinted cases then fire it, ‘BUT’ first index the case, if the problem is in the chamber the case will be ejected with two imprints.

I have no clue where the cases came from, if the cases were new and you know you did not acquire the cases off the Internet check the die and chamber. Next time examine the cases before firing and again after firing, then after sizing.

F. Guffey

[jambrdly]

I will follow your advice. FYI they are winchester cases

JCB

[rg1]

They are factory pressure test cases. I'd toss them or at least closely inspect them and you be the judge. I've bought once fired RP brass and found a couple with the pressure test circle.

[sundog]

I do not remember when or how I came about getting them, but I have a large quantity of '06 RP brass that was sold as once fired as Remington test brass. About 25% of them were so marked by the pressure test. Over the course of several years I culled out the ones so marked after they were several times fired - still sitting in the recycle bin. I am still using the rest of that batch that have no such mark.

[William T. Watts]

I should have added I have Federal, Winchester & Remington cases that have the circular mark, I have fired hundreds of these cases up to three firings without a failure. As long as the cases do not have splits, cracks, loose primer pockets etc I would shoot them. I note nothing unusal about any of the cases I fired. I still have 200 or more hundred 308 cases I intend to fire if I ever pick up another rifle in this caliber! William

[Mike Irwin]

"The cases were pressure rounds using a copper pellet (crusher method)."

I'm not so sure about that.

The crusher tests are normally done closer to the case head. And, if I'm not mistaken, cases used in copper crusher units have a very precise hole cut in them, to allow full pressure to bear on the crusher piston as the hardness of the brass can significantly affect the pressure reading.

[William T. Watts]

I'm very sure about the circular mark below the neck body juncture, I have examples of F-C,W-W, & R-P plus one of the copper pellets that came from the The Local Remington Ammunition plant located in Lonoke, Ar. Additionally I have several hundred cases so marked that I pulled out of lots of brass that went thru Remingtons ballistics lab that was sold to Blue Star Brass and ammo in Searcy, Ar. I purchased the brass from Blue Star in 2007 in lots of 1000 cases in many calibers and sold as once fired brass. Further, the pressure guns chambers are cut to insert the pellet, when the round is fired the case expands and crushes the pellet, the crush of the pellet is measured and the amount of crush is converted to CUP! Google has several articles covering this subject.. William

[Mike Irwin]

Interesting...

Point me to the google articles, please. I'm not finding anything applicable that describes using a whole case for pressure testing, only ones that have been cut to allow full pressure on the piston.

I'm probably not using the correct search terms.

[FrankenMauser]

They're cases that were fired in a transducer fixture.

Copper crusher fixtures require a hole in the case.
(Piezoelectric) Transducer plunger fixtures use a plunger/piston against the brass, but no hole.

[Mike Irwin]

"Copper crusher fixtures require a hole in the case."

That's EXACTLY what I was thinking, and that piezo doesn't require a specially prepped cut away case.

[F. Guffey]

Requires a hole in the case? And the case is designed to seal the chamber and the gas in the case is hot, high pressure, metal cutting gas and now we have a hole in the case, one of the most boring conversations I have have ever heard or read is the one between experts trying to explain the difference between CUP and PSI and Strain etc.. Then there is the ‘no correlation’ thing, and now I am told there is a hole in the case.

F. Guffey

[F. Guffey]

Hydraulic, a hydraulic is a fluid, it flows, it is a solid, it can not be compressed. Gages should have been using a hydraulic, problem, speed, someone with slow eyes would miss gage deflection, unless there was a one way valve in the line. then if only there was something in the chamber besides the gage, wait, there is, the case, the case is in the chamber when the case was tested, but still, no correlation, we do have copper crush, we have lead crush but no brass crush, I have crushed a few case heads, those do not count.

F. Guffey

[William T. Watts]

The crusher method of determining pressure doesn't require a hole in the case, the hole is drilled in a specially prepared chamber, the copper pellet is inserted in the drilled chamber, the crush of the pellet by the case expanding exerting pressure on the pellet can be be converted to CUP when the pellet is measured and compared to a table that has been supplied by whoever supplied the pellets. Google crusher method/Copper units of pressure.. William

[SL1]

Looks like a "conformal transducer" pressure test case to me. Those are typically used by labs that need to run a lot of tests, because there is no set-up between test rounds. The case does NOT require a hole for those, because there is an anvil that exaclty conforms to the chamber wall shape that can slide radially to transfer force to the piezo transducer. The readings need to be corrected for the pressure needed to defect the (average for the lot) case, though.

I don't really care what Google says, my old reloading manuals say that the copper crusher method uses cases that at least END-UP WITH A HOLE in them because the gas needs to impinge on the anvil that is tensioned against EACH copper crusher by hand for each shot. I thought that those holes were drilled ahead of time, but perhaps some were simply blown through on firing?! Anyway, the brass seals around that hole like it seals around the case mouth, or even around a longitudinal crack in a case body, while the pressure is at its peak.

SL1

[Mike Irwin]

" I thought that those holes were drilled ahead of time, but perhaps some were simply blown through on firing?!"

No. I don't believe that they were. They were prepared by drilling prior to seating in the pressure gun.

The piston assembly used a gas check (also replaced after every shot, I believe) that stopped chamber pressure from blowing past the piston and ruining the test results.

I just REALLY changed my google search terms and I found this site:

http://www.frfrogspad.com/intballi.htm

Which has this statement...

"Some set ups also drill the cartridge case which changes the results compared to non-drilled cases."

That's VERY interesting. In other words, BOTH types of case prep (drilled and non-drilled) are used. Probably it varies by the manufacturer of the test equipment.

I'd really like to know how they would factor in the hardness of the brass in testing where the case isn't drilled...

[mehavey]

What I find interesting is that these cases found their way into the reloading world. I would think the
labs would have "de-milled" them (crushed the neck or something) after testing to prevent re-use.

[William T. Watts]

I have never had a failure using any of these cases, usually I fired them 2-3 times before recycling them. I thought I had 500-600 rounds left, I found I have at least 1K rounds in various calibers plus one bag of 30/06 cases with a 1k rounds in it I have never checked. No matter what label you fellows want to put on these cases they are unusual and do catch your attention when you see them! William

[SL1]

It is hard to tell in that fuzzy picture, but it does not look like those circular marks have edges that are actually cut by the edge of the pressure test port. So, the brass should not be deformed in a manner that would weaken it. And, it is in a fully supported part of the case when it is fired in a regular chamber. So, I do not see any reason why these cases cannot be reloaded.

As for why they would be for sale, the only two reasons that I can think of are:

1. the seller can make some money by selling them, and
2. there is a shortage, so throwing away useable brass only makes that worse.

SL1

[orionengnr]

Learn something new every day.
I wouldn't be happy with whomever sold me those, unless it was disclosed prior to sale and they were priced really right.
On the plus side, I guess those marks are not in the worst spot (as far as shortening brass life goes).
Wonder if firing will "iron them out"?

[F. Guffey]

Again, a most boring conversation starts with “Hather said,,,,,” Then “Ackely said........” Just behind those two but jammed right-up against the first two is the discussion about CUP and PSI, cut them out hold them up with the sun shinning through, all the threads are the same, iso, iso, (a Greek term for same-O, same-O).

There there is absent, as in the term “I do not know” is absent. Followed by the insistence there is nothing good, there is only fault in everything.

Reminds me of the men from India examining an elephant they could not see.

I have cases with little ‘Os’, they got their little ‘Os’ before there were strain gages, etc., and ‘NO!’ they keep their little ‘Os’

Reloading forums are eat up with those that can not do, because of variations and inconsistences. Then there are those that assume, like they heard there were holes in test cases, therefore they drilled the hole in the case before they started, again, I say: Gas is hot, it has high pressure, hot high pressure gas is hot high pressure metal cutting gas, and now, someone is going to tell me the ammo testers have test guns that are exempt from rendering their test rifles scrap because they are testers.

No one said the test cases were used to test for failure, the test cases were used to develop loads. And I always say “If only there was something else in the chamber besides the test gage when the trigger was pulled, Wait!, there is, the case was in the chamber when the trigger was pulled” and still, no correlation between a fired case and the test. It is possible for a ‘can-do reloader’ to measure case head expansion, Point? If the cases with the ‘little Os’ had been hammered the case head would be shortened, the case head would have increased in diameter and the flash hole would have increased in diameter.

I was asked to help in forming a few hundred wildcats from belted magnum cases from 8mm Remington Magnum and 300 Win Magnum and everything in between. OH YEAH! I was asked to bring the other #4 RCBS shell holder, I did, I brought a gasket cutting ball peen hammer, it is sort of case friendly when hammering cases into a shell holder after the case has been hammered with heady loads, not strange, the cases that would not fit the shell holder came in sets matched with head stamps, they decided not to use those cases, and? when measured ahead of the belt the cases were from .007” to .011” larger in diameter than other fired cases. I know, they could have spent $80.00+ dollars for a case diameter reducer-ahead of the belt, I will type slower, the cases had been hammered.

http://en.wikisource.org/wiki/The_po...d_the_Elephant

F. Guffey

[Unclenick]

Mr. Guffey is on point about nobody saying the rounds were proof loads or loads tested for failure. Indeed, SAAMI specifies that velocity measurements be taken separately after pressure measurements of the same load. This may be done in a separate velocity test barrel, but it is also allowed to be done in a pressure test barrel, which I suspect is often is because that barrel is already set up and is convenient to use. So it is even possible these cases were velocity test cases and not pressure test cases at all.

The cases in the photo appear to have been fired in a barrel equipped with a conformal Piezo transducer and not from a copper crusher barrel. The main reason I say this is that, in the SAAMI standard test barrel drawing on page 169 (page 175 as Acrobat Reader counts pages), here, a copper crusher piston port for .30-30 is located one inch forward of the base of the cartridge case. Conformal Piezo transducer ports are centered 0.175" below the case shoulder, which is where it looks to me like those rings are centered.

Read through the SAAMI standard at the end of that link for yourself. Page 92 (page 98 by Acrobat Reader's count) says drilling a hole in the case is optional, so I infer they don't think it affects the peak pressure reading much. But they do specify checking piston holes for erosion in that standard, which they say occurs when the gas checks leak. That suggests that even if the brass is not drilled, discs of brass are blown out of the sides of the cases as the copper slug crushes, accounting for why they don't think drilling has much effect on peak pressure and why you still need a gas check even if you don't drill.

The reason for taking the time to drill a hole in the case is brass would flow down into the piston hole during firing as the copper slug is crushed. This would tend to trap the case in the chamber even if the pressure cut a hole because of burrs at its edges. So not drilling adds the effort of clearing that piston hole with a brass drift punch before extracting an empty case. That's means more effort. I expect the choice is the personal preference of the facility test protocol author or the ballistic technician involved as to whether to take the trouble to drill or take the trouble to clear burrs.

Today, SAAMI has standardized on the conformal type of Piezo transducer, whose piston head is a match to the rest of the chamber wall, so that no hole needs to be drilled. This works because the quartz crystal transducers don't compress significantly, so the only mark on the case will be slight brass flow around the edges of the piston hole due to the gap in the piston/hole fit tolerance. Unlike the flat head of a copper crusher piston, this mark is fairly uniformly proud of the case surface all around, where the copper crusher would stretch the brass deeper at the circumferentially extreme ends of the hole.

There is a fairly good article starting on page 116 of the Lyman #46 Reloading Handbook comparing copper crusher vs. Piezo readings and including case pressure ring expansion (PRE) measurements at 0.3 inches forward of the breech end of the case. The article includes detailed schematic drawings of a copper crusher and an older style diaphragm type Piezo transducer that were both mounted, 90° apart, on the same barrel by H. P. White Laboratories to collect simultaneous crusher/Piezo data for each round for the comparisons used in the article. It mentions that holes were drilled into the cases for both. That diaphragm type transducer did not have a piston head conformal to the chamber, but used a gas check, same as the copper crusher. I believe the CIP still uses this type of transducer and still drills holes in cases for testing, but my information on that is not very current.

PRE proved to be a poor pressure indicator, giving no readings below 15,000 psi and little to no response differences above 45,000 psi. An expansion of 0.006" in the .30-06 cases tested was measured with anywhere from 45,300 psi to 59,500 psi.