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Old November 22, 2006, 06:45 PM   #1
timothius
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Signs of too much pressure

I am really new to reloading so please indulge me on this one. Could somebody please tell me what the signs of too much pressure on a brass case would look like. I have been working up a load but I realized that I have never seen a caes that was subjected to too much pressure. Is there a web site that has some pictures on it. I am a regular dumb*ss and pictures really help me. By the way I have been working up a load on my 45 ACP and it has been fun, but trying. I start with a 200 grain plated Rainier bullet over 5.1 grains of Unique. I am now at 6.6 grains of Unique and all is still good. But I want to be sure of the signs before proceeding. All of the other brass looks the same as the lowest start load. I really wasn't expecting to get as high with the Rainier.

Thanks for all of your help.

Tim
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Old November 22, 2006, 07:16 PM   #2
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A good sign of too much pressure is primers that look flat another is your slide sticking out of your forehead lol just kidding. The primers are a good sign though
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Old November 22, 2006, 08:49 PM   #3
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-Flattened primers.
-Flowing primers or firing pin smearing.
-Light colored ring at the base of the case near the case head.

Worth noting that the above aren't always pressure related. Could be signs of improper headspace or other gun related issues.

I'm out on a limb here but it sounds like you're flying blind without a single load book. All the name brand load books discuss this stuff in detail, including pictures. If this is the case you're asking for serious trouble. Spend the 30 bucks now and save yourself a trip the the ER. Losing a few fingers and an eyeball is one thing, destroying a perfectly good firearm is another matter all together.
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Old November 22, 2006, 09:18 PM   #4
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Go here http://stevespages.com/table3.html and click on "Diagnosing Problems" under "Case Information".
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Old November 22, 2006, 09:34 PM   #5
timothius
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Ares45

Actually I am using the Lee 2nd edition of modern reloading. They have a picture of 3 shells 1, normal, 1 never exceed load ,and one that was loaded hot. I hate to say it but I see very little difference in those that are pictured. That's why I am asking this question. So no I am not flying blind, but may as well be as the picture that I have seen are not very good to me. In fact! The primers of my factory ammo such as federal or CCI Brass look like the the picture of the so called hot load from my manual. So maybe my factory ammo is too hot?? This is an interesting situation.

However if i used the information in the Lee manual alone I am far and beyond the safe load for this particular combination, but several other books give vastly different info. So I am trying to find the best answer. I feel that I am getting close but still a bit off.

The powder that I am using is Unique It burns fairly dirty. I have been told that the closer that one gets to a good load with Unique the cleaner it burns. Mine is still pretty dirty. That's why I asked my question. I am just trying to get the best load and still be safe. Manuals are very expensive I will buy another when I can afford it.

Thanks for your concern, but I don't think that I have reached a over pressure situation. My primers still have rounded edges and are not flattened at all.

Regards

Tim
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Old November 22, 2006, 09:47 PM   #6
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I had the same issue with my Lee load book. Better pictures were found in the Sierra Manual, IMHO.
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Old November 22, 2006, 09:54 PM   #7
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I have read and read and read about pressure signs and have come to one conclusion. No one knows. Some praise flat primers as a sign of too much pressure, some dismiss it. I can tell you first hand that flattened primers can also be a cause from too much head space. I had flattened primers and when I switched to neck dies, the flat primers went away immediately. The light ring around the web is another common belief that there is excessive pressure. This just isn't the case. Unless you have a custum made match chamber with very tight tollerances, you are always going to get this ring. Because the factory chamber is much larger than the brass, when fired, the brass expands to the chamber walls. Thing is, the case head is solid clear up to the web, so it does not expand thus the ring you see on the outside of the case. After you resize with a full length sizer a few times, this area gets weak from getting worked so much and can cause case head separations. I think the only way to know is if your gun blows up LOL. A chrono is a great tool. I would never go above book max's so if your at max and not getting the speed you want, you'll just have to try a different powder. And a powder getting cleaner when get close to the load you need? That one made me laugh.
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Old November 22, 2006, 10:52 PM   #8
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Actually, there is no one pressure sign that is reliable, and in rifle you get some different ones than pistol. Flat primers, as stated, are common to both. They constitute a warning that you are starting to get close, but usually they start to flatten out before you are at maximum. In truly hot loads they are more than just flat; they flow outward at the edges of the primer pocket so they have a slightly mushroom-headed profile when you decap them. Depending on how tightly your firing pin fits, they may flow around the firing pin and into its hole, so the firing pin indentation looks like a lunar crater with the edges of the indentation raised above the flat of the primer like crater walls. This, appropriately enough, is called cratering. However, if your firing pin is loose in its hole at the end of the firing pin tunnel, cratering can begin at perectly acceptable pressures.

In a rifle the solid casehead will actually expand under high enough pressure. This causes the primer pocket to stretch so it doesn't properly retain primers anymore, but a .45 ACP will be overpressure before that happens. If you have a standard 1911 type barrel, you will see the cases start to bulge slightly where they overhang the feed ramp portion of the chamber as they get to maximum pressure. Cases that start to show increasingly deep extractor marks are probably too warm. If you see cases wear out quickly ou are prpbably running too hot.

You will also find the slide batters the frame harder as loads get too hot. If you shoot a bit of hardball through it to get the feel, you can tell if you are hammering it harder with your reloads.

The reason Unique will appear to burn cleaner near maximum is that it burns faster as the pressure gets higher, and will burn hotter and more completely while the bullet is still in the barrel. This cuts back on the unburned flakes you find and to some degree on the soot. For example, a hardball pressure load for a lead 200 grain bullet of 6.9 grains will burn about 93% in the tube, while a target load of 4.5 grains under that same bullet will burn only 76% before the bullet leaves the muzzle. The target load will therefore be dirtier. That said, this old powder's graphite coating will always leave a lot of black dust with the soot. And even at 6.6 grains you are close enough to a maximum load to be burning almost 92% in the tube, so you don't have much difference to look forward to. You might consider Hodgdon Universal Clays if you want a cleaner alternative. About 6.2 grains should get near hardball pressure with a 200 grain lead bullet and will burn 99% in the tube and it has no graphite.

As to your true maximum load, frankly even hardball, if it isn't military, will usually not be at maximum. Lyman puts their 200 grain cast bullet maximum at 7.5 grains of Unique. Hornady uses 6.8 grains as a maximum for their 200 grain lead bullets. Lee's book only shows 5.1 grains for 200 grain lead bullets because that is a target load. You'll note the pressure is half what they allow for the jacketed 200 grain bullet with 7.1 grains of Unique.

Exactly what you can get to with the Ranier depends on the depth you seat it too, and this depends on the bullet dimensions. One problem with a straight wall case, and especially with a short straight wall case, is that the depth the bullet seats into the case only has to change a little bit to significantly change pressures. If you find loads in the range of 6.8 or 6.9 grains satisfactory in performance, I would stay there. If you want to keep working up toward the Lyman limit, go very carefully and be aware that you can shoot hot loads that are safe, but which will wear your gun out faster. You will also likely encounter more metal fouling in your bore driving these soft bullets to the max.

Nick
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Old November 22, 2006, 11:16 PM   #9
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Do you have a chronograph? One way to check for high pressure is to check velocity. If the bullet is moving faster than the max loads in the manual, you can be sure you pressure is over max.

FWIW, in Speer No. 13, the loads for Unique and a 200gr. bullet run up to 7.3gr.

I have never trusted myself to recognise high pressure by looking at a case or a primer. (Unless its WAY over max.) Just stick to published loads to stay safe.
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Old November 23, 2006, 12:05 AM   #10
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DaveR is giving some great advise about a chrony!
Several chrono'd speeds and several referencing load manuals will help you not guess too much.
Reading primer sign is generally taken from an extra high intensity overloaded rifle round, not a pistol round.best-o-luck
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Old November 23, 2006, 12:38 AM   #11
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Your loads are reasonable for a 200gr bullet. If you find a lot of leading in your barrel after shooting, you should back off your loads, switch to harder cast bullets or jacketed bullets. Additionally, be sure to clean the leading out of your barrel as it can build up and increase pressures.

Any time you are concerned about pressures is a semi-auto pistol, examine a couple of spend cases for;
  • Flattened primers with obvious breechface markings on them.
  • Bent, ripped or gouged case heads where the extractor pulled the case out.
  • Bulging of the case near the base, just above the extractor groove in one area.
  • Cratered primers
  • Smeared or flattened case head markings

Because most semi-autos do not fully support the case head at the 6 o'clock position when a round is chambered, bulges can appear only in a small section of the case near the extractor groove. Stop shooting these loads and back off your powder weight. If a case ruptures, it will blow hot burning powder, under pressure, down the magazine well. This may cause the mag to be blown out of the gun and damage the gun, grips, your hand and perhaps blow hot powder towards your face!

Flattened primers may have flowed outward to fill the primer pocket, perhaps in an uneven pattern. When this happens the primer usually picks up any tool markings from the breechface.

Deformed case heads or extractor grooves indicate excessive pressure shoving the case against the breechface or the case expanding tightly in the chamber and the extractor almost failing to extract the empty.

One more factor to consider when evaluating loads is the bullet type.

The Speer manual lists a 5.3 gr Unique load as max for their 200gr LSWC and 7.3gr Unique as max for a 200gr JHP.

The jacketed bullet will have more friction than the lead bullet and require a somewhat stiffer charge to drive the bullet to effective speeds.
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Old November 23, 2006, 08:39 AM   #12
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Folks,

Thanks everyone for the help! Steve, the web page is exactly what I was looking for. Thanks Unclenick for the information, it really helped. I feel that I am very close, if not on the load that I want for my 45 auto with these bullets. They shoot well, accuracy is good and they are fairly inexpensive.

I struggled with the conflicting data both form rainier and my Lee book. as my Lee book said 5.1 as start load and 5.1 as Never exceed. Rainier's info was shoot as lead, which I used the Lee data aformentioned or 10 percent less than jacketed with was a whopping 6.03 grains of Unique. That's almost a full grain of pwder higher than the 5.1 Maximum load for lead bullets in the Lee manual. So I really wanted to make sure of what I was looking at in my spent cases. As I said before I am a regular Dumb*ss, and need all the help that I can get. I appreciate all that was said here. I think that I will start to look at another powder as Unique is just too dirty for my tastes. I also think that a chronogragh is in my future too.

Thanks again to all.

Tim
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Old November 23, 2006, 10:40 AM   #13
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6.6 probably isn't max,

but it's getting closer.

According to the data from Alliant (www.alliantpowder.com), max load for a 200 gr, JHP is 7.1 grains of Unique. As you are using Ranier bullets, you should hypothetically back that down, as the 7.1 gr is for jacketed bullets. However, an examination of other Alliant data shows that they recommend the same load of American Select (5.4 gr) for a 200 gr LSWC as for a 200 gr JHP. (American Select is the only one they list for the 200 gr LSWC.) So by extrapolation, one might assume that 7.1 gr of Unique would be a safe max load for the Ranier bullet. I say might assume. You are responsible for your own actions.

That said, I've been shooting 6.8 gr of some old Unique under a 200 gr LSWC in IDPA out of a Ruger P90. Never a problem going bang. Can't tell any difference in recoil or report compared to factory jacketed ammo.
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Old November 23, 2006, 01:08 PM   #14
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As I said, the 5.1 in the Lee book is for a target load. They put it in the not-to-exceed column as well as the starting load column because they wanted to keep it a target load, and not because it is dangerous to load higher. Their own pressure for that not-to-exceed 5.1 grains is under 10,000 PSI. Normal max is 19,000 PSI for the military loads, with 21,000 being the SAMMI piezo method PSI limit. So blow that off to Lee not making the distinction as they should have.

Like chronograph manufacturers, I do NOT recommend you rely on chronometer readings as any kind of load indicator. For one thing, the same load can vary 100 feet per second from one gun to the next, depending on internal dimensions. For another, many inexpensive chronographs may not be relied upon to have great accuracy. You see lots of good user reviews for some, but when you think about it you will realize their absolute accuracy are not being checked against anything but themselves. What the reviewers are telling you is they didn't have any apparent malfunctions and the readings seemed reasonable so they expect it is accurate. It’s not checked against an objective standard. It’s like having an electronic scale with no check weight to calibrate it.

I've seen the very reliable Oehler 35P with 4 foot screen spacing and check screen disagree by 200 fps with a less expensive unit with 1 ft spacing. The same unit’s reading would change over 100 fps depending on the angle at which you tilted it into the sunlight. This kind of problem caused the IPSC nationals to go to using an in-line pair of CED Millennium chronographs (a make with good accuracy reputation) inside black boxes with powered artificial IR light sources for determining power factor. They have to get agreement in the readings, don't trust natural light and don't trust any one unit to get it right every time. The Oehler covered this last problem with its check screen.

The PVM-21, made by a German company that specializes in high speed electronic switching and detection, is likely the closest thing to lab grade instrumentation for home use, but costs over $700. It also relies on a powered artificial IR light source. Most home units are good for looking at % velocity variation, but their absolute accuracy is not something to let your safety rest upon. Keep watching for pressure signs. Don’t trust any one pressure sign alone. Read this, for example.

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Old November 23, 2006, 01:38 PM   #15
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Bolt sticking while trying to extract is one.Loose primers is another(like when they fall out.Blown primers is another.Some signs are not definate but you would be foolish not to check for them..I have fired some nato 223 rounds in my tighter chambered ar15(Not smart )and found One that expanded the primer pocket so much a primer would rattle around in it,as well as almost ripping the head from the case while it extracted..Usually in my rifle the hotter loads tend to push the primers flat and out to the outside ring of the primer pocket(you can notice the difference between slightly flat and so flat you can barely see a gap )..The signs are real but can be read wrong very easily.The chrono is the best aid(getting you in the ballpark of safe velocity) in figuring were you are safe and not in relations to reading the pressure signs more accurately..JMO
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Old November 23, 2006, 10:33 PM   #16
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Bolt sticking isn't likely in his .45 ACP. However, a common list of pistol & rifle pressure signs might be a useful post. In the the interim, a search of the forums will uncover them all.

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Old November 24, 2006, 01:10 PM   #17
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Oops,I guess I missed the 45acp part of the question.I was thinking bolt action with a bottle neck.I sometimes miss the little details
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Old November 24, 2006, 02:05 PM   #18
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The third 308 round is starting to show excessive pressure but stll safe. A 45 will probably blow a hole in the primer before reaching 10 but this gives you an idea as to what to look for.
Attached Images
File Type: jpg 308dscf0003small.jpg (36.7 KB, 2786 views)
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Old November 24, 2006, 02:25 PM   #19
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When using primers to evaluate pressures, some consideration should be given to the type of primer used as well.

I recently loaded a large quantity of 9mm using CCI primers. In the batch 100 cases were primed with Winchester primers.

Shooting the same bullet, the same powder load, and comparing cases of the same manufacturer, the Winchester primers had expanded to fill the entire primer pocket, including the chamfer. When the primers were removed, the winchester primers were "mushroomed" while the CCI primers were not. None of the cases showed signs of overpressure, just the mushroomed winchester primers.
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Old November 25, 2006, 02:14 AM   #20
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molonlabe, I can tell just by the firing pin strikes that those are Fl sized loads. Unless your firing pin is horribly out of line with your chamber. And another thing that was mentioned was primer brand. In my experience CCI are harder to flatten than any other. I think those .308's have improper headspace and flattened primers can be discredited as a sign of over pressure. I've shot plenty of my first (improperly headspaced) loads that extracted fine but had flattened primers. When I switched to neck sizing, all my flattened primers went away even with Win primers and max charges. I also think that the instructions that come with FL dies are junk and just cause wear on your brass and rifle. FL dies instructions ought to say "If your not using a semi-auto, go buy some neck dies". Just my opinion.
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Old November 26, 2006, 12:10 AM   #21
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Their not mine but taken from this board. Each load was increased a few percent over max.(sorry I could not find the original post0. I suspect it was a bolt action given the placement of the brass flowing into the extractor. I own a match M1A and I would never test loads like this in my semi but I think it is a good illustration of what to look for which is why I saved the image. CCI is known to be harder than other primers but if you experience cratering flattening of primers or flowing into the extractor you have pressure warning. That was the question asked.
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Old November 26, 2006, 01:24 AM   #22
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I don't see how this is a good illustration as to what to look for. They all look exactly the same to me until 9 and obviously 10. The only reason 9 looks any different to me is the wear on the T in Winchester. Those primers aren't even filling the entire primer pocket. And the wear on the T just might be a manufacturing defect. I've got pieces of new, never been shot Win brass that has imperfections on the case face so bad that I had to throw it away. About 3 per 100 actually.
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Old November 26, 2006, 10:02 AM   #23
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Swmike,Im with you on that one.My ar15 while loading my 70gr-80gr will do just what they did in those pictures.Thats using a collet neck sizing die with the rcbs precision mic to check my shoulder displacement..The winchester primers are just soft and I like that because it helps give me an early warning of high pressures..My bolt face has a slight chamfer at the end were the firing pin exits so My primers have that look almost all the time except for the when loading the lightest loads..I have never blown a primer except when trying some NATO 5.56 once(not a good idea in 223 chambers ).Expanded primer pockets are a definite sign of over pressure If they happen all of a sudden.Along with blown primers..
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Old February 20, 2011, 03:32 PM   #24
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I primarily use Winchester primers. I looked at 4 or 5 different fired brass out of different types of guns and all the primers were somewhat flat. I never load to maximum. I think Winchester (and other brands) primers flatten even with modest loads.

Just noticed that when I prime with my Forster press, the primers are somewhat flattened do to the strength of the press.

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Old February 20, 2011, 05:37 PM   #25
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Actually, if it's the Forster Co-ax press, it has a unique primer seating system that ensures the primer is 0.004" below flush with the case head. That's for floating firing pin military gas operated rifles. It's a good system. The slight flattening doesn't hurt and actually sets the bridge for most reliable ignition.

In the case of pressure signs, look at how the primer goes in and how round the heel is as the primer cup bottom transitions to the sides. That's what flattens out. Some flattening is normal. Also note that different brands of primers have different cup thickness, so the pressure at which this happens varies with the brand. When you use a primer for pressure signs, you are seeing what pressure does to the primer and are loading to the primer. It may or may not have much relationship to what pressure is doing to the brass or to rest of the gun. Nonetheless, having primers piercing damages the breech face with gas cutting.
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