Quantcast
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Identifying signs of excessive pressure

Discussion in 'Handloading and Reloading' started by Timothy, Jan 9, 2003.

Thread Status:
Not open for further replies.
  1. Timothy

    Timothy Member

    Joined:
    Dec 27, 2002
    Messages:
    73
    I’m just gonna be honest here:
    I hear so much about pressure signs and I’m not sure I ever saw any! Either I never had any or I didn’t recognize them. At the range guys are always trying to be nice and helpful but I’m not sure their observations are always factual. I’ll show a fired brass to one guy and he will say it looks to have been loaded a little hot. I’ll stick it in my pocket and later show it to someone else and they will say it looks normal to them. I really do appreciate their intentions, but can I count on their opinions? I always start at the bottom and work up my charges, but I’m not sure where to stop. I’m sure if I saw a split mouth I would back off but I don’t really want to be “closing the barn door after the horse is outâ€. The important words here are “signs of excessive pressure†. Sounds like a matter degree and I’m not really sure I could identify and interpret them correctly. For instance, flattened primers. I use Federal and they are always flattened. I’ve learned that this their nature so I’m not too concerned, but how flat is “too flatâ€? What conditions, and how severe, are telling me that I am entering the danger zone?

    I appreciate anyone’s help to make me more correctly observant.
     
  2. Dave P

    Dave P Member

    Joined:
    Dec 24, 2002
    Messages:
    1,600
    Location:
    North Florida
    Couple of brief thoughts:
    If you have trouble extracting the brass, watch out.
    If your primer starts cratering (flowing into the firing pin hole), watch out.

    And of course read and heed the manuals! Many are online. Stick with "standard" loads until you gain more experience. Don't try to invent something new (reminder for self!), and don't rely on internet loads!:)
     
  3. MoNsTeR

    MoNsTeR Member

    Joined:
    Dec 29, 2002
    Messages:
    790
    Location:
    Lakewood, CO
    Primers flow slightly into the firing pin hole of my wife's Beretta 92 no matter what. Winchester white box, Fiocchi, PMP, full-power handloads, super-light handloads, doesn't matter.

    I share Timothy's question, how do you tell?
     
  4. colima

    colima Member

    Joined:
    Jan 9, 2003
    Messages:
    34
    Location:
    San Diego
    I don't want to hold myself up as one of the wise old timers on this list, but I have done a lot of reloading for .45 ACP and .357, along with a bit of dabbling in 45 Colt.

    My opinion is that overpressure signs will vary from gun to gun. With my .45s (three Kimbers, a Norinco, and a Colt) I see the following signs when the pressure gets too high:

    1. Flattened primers - yes, I know they all look flat and that some primer brands are softer than others. But a really high pressure load will REALLY flatten in my guns - including flowing into the curved edges of the primer hole. The size of the firing pin indent is sometimes reduced when the primer really flattens.

    2. I tend to use brass until it either splits or won't fit the gauge anymore, so split brass is not always a sign of overpressure - its sometimes a sign of really old brass. But if you get splits on relatively new cases, that can be a overpressure sign.

    3. For autos with barrels that do not completely support the brass (most unramped .45s), a good sign of overpressure is bulging in the case near the bottom where the case was not supported. I set up one of my Kimbers with a Schueman ramped barrel just to experiment with .45 Super - because of the better case support.

    4. As noted by others, for revolvers brass that sticks in the chamber during removal is a possible sign of overpressure. I have had inconsistent experiences on this with my .45 Colt. I have had medium range loads stick while Paco-level loads popped right out. Sticking has however been a pretty reliable overpressure indication in my .357 loads.
     
  5. KP95DAO

    KP95DAO member

    Joined:
    Dec 27, 2002
    Messages:
    229
    Location:
    Central Oklahoma
    The "pressure ring" method is the best barring pressure equipment. I have been using this method for over 20 years and have never had a surprise. It is useful in dealing with any round that generates 20,000 or more. It, in cunjunction with a cronograph, will allow you to go where mere mortals fear to tread.
     
  6. redneck2

    redneck2 Member

    Joined:
    Dec 25, 2002
    Messages:
    10,453
    Location:
    Northern Indiana
    Good question...

    there was an article in Handloader titled "Pressure Guessing"

    this should be required reading for everybody that's a handloader/reloader

    it was VERY detailed, but basically, what it said was there is no reliable way for the average person to test pressure other than velocity. The pressure ring method has been the holy grail for a number of years now, but it's only marginally accurate

    there's a lot of conjecture about the "old" reloading manuals and why some of the info has dropped so much. What they found out was that some of their loads had way high pressures but weren't giving any typical signs.
     
  7. Edward429451

    Edward429451 member

    Joined:
    Dec 24, 2002
    Messages:
    2,251
    Location:
    Colorado Springs Colorado
    Pressure ring method??

    Are you guys talking about the bright ring that shoes up after resizing near the base of the case? I think so but noone went into any depth on it so I want to be clear.

    If so, thats what I mostly use on rifle rounds for my method. If its too bright I double check with a paperclip bent 90 deg on the tip and feel in the case to see if there is ANY ridge or bump felt in the area of the ring, if so I toss it. If its scored at all, I toss it. When in doubt I toss it. Brass is cheaper than rifles. (credit that idea to CRSam or Art, cant remember..)

    If I'm out in left field on what you guys meant, by all means please expound on the subject a little. Thanks.
     
  8. Timothy

    Timothy Member

    Joined:
    Dec 27, 2002
    Messages:
    73
    Redneck2:

    Sure would like to read that article on "Pressure Guessing"
    Could you please guide me to it?...or... Would it be to much of a pain in the arse to scan and attach to an email? My address is in my profile.

    Appreciate all your help, thanks.

    Timothy
     
  9. Big_R

    Big_R Member

    Joined:
    Dec 27, 2002
    Messages:
    384
    Location:
    That little strip of land between New York and L.A
    Timothy:

    The best advice I can give you is stop when you reach the maximum listed in the manual provided by the powder manufacturer. Any loads above maximum is not only asking for trouble, it is hard on your gun regardless of if you get pressure signs or not. I have seen guns that have had significan failures because someone was trying to turn a 30-06 into a 300 Win mag. Use your firearm for the load it was designed for. The extra couple hundred fps you achieve by overloading is never worth it. End of rant.

    Pressure signs: The most common pressure signs vary for the type of weapon and are pretty much covered in the previous responses. Any weapon that works smoothly with factory loads and starts jamming, failure to extract, or difficult bolt opening can be a sign of excessive pressure. With a long gun, excessive recoil is an obvious sign, but it's probably too late.

    Ryan
     
  10. KP95DAO

    KP95DAO member

    Joined:
    Dec 27, 2002
    Messages:
    229
    Location:
    Central Oklahoma
    Another topic I, "The Heretic", know something about.

    Once again something is said/printed, "The pressure ring method has been the holy grail for a number of years now, but it's only marginally accurate.", which proves that you can hand a tool to a monkey and it will do him no good. The monkey must have the ability to think, analyze, and act on data presented to him.

    The Handloader magazine is not what it was 25 years ago. Back then there was not the constraint of possible liability due to some ignoramous trying to deal with complicated subjects presented in it's pages. I haven't subcribed for over 15 years because of the dumbing down of it's topics and their content.

    If there is enough interest I will write up the procedure and techniques of using the "pressure ring method." Let me know if you are interested.
     
  11. Timothy

    Timothy Member

    Joined:
    Dec 27, 2002
    Messages:
    73
    KP95DAO:

    I, like a lot of other guys, would like very much to see the procedure and appreciate your effort.

    Timothy
     
  12. Pistolsmith

    Pistolsmith Member

    Joined:
    Jan 4, 2003
    Messages:
    158
    Location:
    Pacific Northwest
    KP:
    If you have 86 million dollars worth of liability insurance, go ahead and write it up because we'd all be interested. But, make no mistake: As the man said about monkeys with tools, somebody will misconstrue what is stated even if it is words of one syllable.
    Handloader was never at the top of the game. Also, they hardly ever paid their writers. When it was first on the stands they had a brilliant series of articles on pressure amd how other elements resulted in different pressure levels. If you can find the series, don't believe it; most has been proven only marginally true even though Dr. B used his university's computer and had access to the physics department.
    Almost NOBODY knows how to measure water capacity of a case, and even if this is done very carefully, and is fine for certain guns, harken to what the poster said about his wife's Beretta jacking up pressures on normal loads.
    One outstanding problem is that if you are a real old timer in reloading, all of your hard earned data from the past is unreliable. Modern powders are made in different factories now and they seem to vary significantly from older data. So, if your old data approached the red line, re-test and re-record.
    As for the Beretta cited above, if it is a recipient of the so called NATO chamber it MIGHT not show pressures in excess due to the long throat ahead of the chamber. Other barrels could show flattened primers. Or, if bullet seating depth changes, strange effects begin to show. Even harder or looser taper crimps will have their effect.
    The worst pressure signs I have ever seen came from a pistol that never had a problem that way before, but suddenly the primers were almost blowing out. I discovered that the "pressure signs" came from ammunition that had been stored primer down in the back of my 4X4 that had bounced over logging roads for several weeks before the fodder was fired. The constant shaking had jarred some of the retardant coating loose from the granules and a very fine dust had settled into the primer, causing very high pressures. A return to normal ammo returned me to normal pressure indications.
    Once, when testing a friend's .45 magnum pistol, we found that some very excessive loads used as a pressure test cycle on the pistol he had built in prototype, showed up absolutely the same as much lower pressure loads we had been firing.
    In firing my 9X23 Win caliber pistols, I found that identical loads with virtually identical water capacities and uniformity of loading settings resulted on brass being scuffed off the case head on some days and was less noticeable on other days, perhaps due to ambient temperatures being different.
    The only real identifier would be from Oehler's device that uses a strain gauge, but ammo that passes the test would still be subject to the "Beretta phenomenon" our poster mentioned.
    If you need a tad more velocity, you might consider buying one of the computer programs that purport to give pressure readings. I bought a rather expensive one made in Germany and found that it was based on lots of obscure powders and some "just likes" that weren't.
    Pressures in firearms falls under the category of physics, not handloading, so until somebody comes up with a method of measuring pressure in each individual handgun or rifle, it is by guess and by body english.
    "You sure you used enough 3N37 there, Butch?"
     
  13. mete

    mete Member

    Joined:
    Dec 31, 2002
    Messages:
    3,579
    Location:
    NY
    Some years back Norma had a great idea. They realized that the handloader had no instruments to measure pressure, so they made cases very precisely so that pressure signs would show up at the max pressure of the cartridge. These cases are marked Re on the headstamp. Unfortunately there are lots of dummies out there, one group thought that the " Re " meant that they had been reloaded , and the other group , used to loading to 70,00 or so rejected the cases as being far too soft. So norma scrapped the idea. There was an article about reloading the 7mmrem mag using the criteria I think of .0005 expansion of the head. He then sent the loads to a lab-- 70,000 psi. When you criticize gun companies for legal stuff ( do not use reloads etc ) remember that they do it because there are many shooters who don't know what they are doing or they are downright irresponsible. Reloading books are made with much time effort and cost and if you follow that advice you'll never have a problem.
     
  14. Edward429451

    Edward429451 member

    Joined:
    Dec 24, 2002
    Messages:
    2,251
    Location:
    Colorado Springs Colorado
    I'd be interested. It sounds like a good read.




    Following in someone elses footsteps that did or made something is like trying to use someone elses recipe for soup. If a single aspect of it is deviated from like an ingrediant or cooking time The soup is not the same. It may be close, but it is not the same. You'd think it would be common sense that people would realize this. Even copying a reload from data from a published source with specific conponants is not to be regarded as the same in my mind. The conponants that they used even if the brands the same can not be reasonably construed to be the same, because the manufacturing run or lot will have variances in makeup and will yield different pressures. The data is general guidelines only. Don't they teach logical thinking anymore? God help us all.
     
  15. MoNsTeR

    MoNsTeR Member

    Joined:
    Dec 29, 2002
    Messages:
    790
    Location:
    Lakewood, CO
    No, in fact, "they" do not :fire:

    I would also like to read of this "pressure ring" method.
     
  16. JSR

    JSR Member

    Joined:
    Jan 1, 2003
    Messages:
    108
    Location:
    Oregon
    Heres the link to Stan Watsons(OKshooter) site,about the most comprehensive regarding pressure signs that I'v seen.
    Jeff
    w.reloadingpro.com/http://www.reloadingpro.com/
     
  17. Poodleshooter

    Poodleshooter Member

    Joined:
    Dec 30, 2002
    Messages:
    1,237
    Location:
    Mr. Jefferson's country
    Personally, when I develop a load I run it up until:
    A. The primer flattens (I use hard CCI's so this is a useful measurement.)
    B. I see any extractor mark wear on the case
    C. The bolt handle feels sticky or extraction is otherwise difficult or altered

    I see these signs appear in "A,B,C" order everytime I work up a load too high. I always quit increasing charges when I see B, but occasionally "C" crops up at the same time.
    I'd use the micrometer/web measurement, but I don't have one yet.
    It's not pressure guessing, it's pressure assumptions based on prior experience and testing :)
     
  18. Pistolsmith

    Pistolsmith Member

    Joined:
    Jan 4, 2003
    Messages:
    158
    Location:
    Pacific Northwest
    Poodocker:
    You have left out so much vital information that what you have said is virtually meaningless.
    You need to state what kind of rifle, the caliber and note whether the chamber falls within SAAMI specifications for this caliber and if the dimensions are on the low or high side of the tolerance given. Yup, you need a micrometer.
    You need to give the diameter of the throat.
    You need to give the groove diameter precisely.
    You need to determine how much excess headspace your rifle has by closing the bolt on a cartridge and a small piece of steel shim stock. Remove the striker for safety reasons. This rearward expansion can be a factor in weakening the case at the web and giving false "stickiness" feel on extraction.
    You need to state what cases you use and whether they are unfired or reloaded and how many times reloaded.
    If reloaded, state what die set you use and if it full length or merely neck sizes the cases.
    Then give the length of the throat and the proximity of the bullet ogive to the rifling, i.e., a slight gap of X thousandths, touching the lands, etc.
    THEN give the bullet make, weight and powder charge.
    Obviously, you don't need any of the above to "wing it" with your rifle, given your experience at handloading. But, there are first time reloaders on this forum that are going to take what you say as a guide. If they have a different rifle, caliber, different ammunition and loading dies, use different brands of case, primer, powder and bullets the observations you have made just might result in different results than those you have had for all of those years.
    You could spend a day or so pondering your definition of primers flattening. Just beginning to lose the roundness at the edge of the primer pocket, totally flat, ironed out flat, picking up some kind of characteristic like ironed out primer indent, rudimentary flow into the firing pin hole, etc., etc.
    One man's rifle may show these things out of sequence as the pressure spikes. Someone who crimps the case mouth may find yet another set of clues.
    I've seen rifles that were carefully chambered by a gunsmith who was a member of the Pennsylvania Original 1500 yard shooters that fired rounds approaching proof pressures that would befuddle someone trying to use your criteria.
    The best you can say is that you have not had any problems to date (or have you?)
    What you are doing is only for very experienced handloaders who like to live on the edge. Frankly, I have never heard of a target or a game animal that could tell the difference of fifty to a hundred feet per second difference in velocity of the bullet.
    If you are a first time handloader, do not deviate from the book, and compare the reloading book to the powder maker's data book.
    If you decide to use the scrape marks on the case as an indicator, there are several things that could make your rifle's ballistics different from the person's rifle who gives the instructions.
    He may have a bolt action and you have an autoloader.
    You may use small base dies.
    Your chamber may be slightly funnel mouthed for certainty of feed.
    Etc.
    Then, there are handguns that don't give up this "seat of the pants" data as easily as a rifle, and the consequences could be that somebody is hurt. Trust the loading book author, not the self-styled reloading guru at the range.
    And, if you feel that you need more velocity than max loads, consider that you may be using an inferior bullet design. Some of the most expensive ones out there are ineffective under certain conditions.
    I'm not trying to be difficult; I'm just worried whenever I sit down to a shooting bench to the right of somebody I don't know. I've been seriously hurt twice due to other people's handloads and I hate hospitals. Been in the E room twice in the past two weeks and I've seen enough of it. I don't think you'd enjoy going through what I've been through.
    So, remember that when using some powders, the pressure curve spikes straight up with little to no forewarning signs.
     
  19. RobW

    RobW Member

    Joined:
    Dec 27, 2002
    Messages:
    564
    Location:
    Henderson, NV
    Wow, after reading some posts:

    Don't reload!Don't reload! :uhoh:
     
  20. KP95DAO

    KP95DAO member

    Joined:
    Dec 27, 2002
    Messages:
    229
    Location:
    Central Oklahoma
    Remember: Light a candle instead of cursing the darkness.

    Pistolsmith,

    You are obviously unaware of some of the powders I use. The discussion of said powders were verboten on TFL and, since the same crowd is running this site, I would think said discussion would not be welcome here either. That being said, I pay attention to every detail of my reloading. Almost anal in that respect. Thank you, father and mother.

    As far as things out of the blue, no pun intended, I experienced the reported pressure spikes with Blue Dot at under 32 degree temperatures. And then I turned right around and loaded some more rounds to make sure of the loads and then subjected them to the same conditions and got the same results. I don't know why it happened; but, it did.

    As time allows I will put down what I know about this method. When it is ready I will post that it is available.
     
  21. Pistolsmith

    Pistolsmith Member

    Joined:
    Jan 4, 2003
    Messages:
    158
    Location:
    Pacific Northwest
    Nobody said don't reload. What was said is, stay under the maximum loads in the loading books and compare what the loading books say with the powder maker's literature. That should not discourage anybody. Use your head and don't believe everything you hear from the reloading gurus without verifying it or you may find your operation moved to that great reloading room in the sky.
    The proof loads I mentioned above were loaded with blue dot powder. Try your experiment with some of the newer powders like those from Finland and report your findings. I know what I found.
    In 55+ years of handloading (I began in '46 with a Lyman tong tool) I have known several people who always pushed the edge of the loading envelope. My knowledge of them did not show much advantage in going into the red, but what bothered me was having to investigate a death and two maimings that happened on the range and my own two encounters with hyper velocity loaders who had accidents that put me in the ER.
    And, I don't want anybody to feel he has been slighted by anything I have said. I am in no way connected with this web site; I have my own.
     
  22. Dan Johnson

    Dan Johnson Member

    Joined:
    Jan 4, 2003
    Messages:
    15
    Pistolsmith, Big R, and Redneck2 have offered some good advice and info here. Unfortunately, much of the rest falls under the heading of "a little knowledge is a dangerous thing".

    Dan Johnson
     
  23. colima

    colima Member

    Joined:
    Jan 9, 2003
    Messages:
    34
    Location:
    San Diego
    I fear that I am heading into territory where I'll get flamed, but I need to observe that much of the advice that is offered on this thread about reading the manuals and following their advice really does not apply in all settings. In particular, most of the official load data for .45 Colt is limited by the weaknesses of the Colt SAA and its clones.

    Many people, including myself, have loaded Rugers in this caliber to much higher performance levels. Some Ruger data is beginning to appear in official manuals, with appropriate warnings about not firing in other guns. Still, most of the intelligent discussion on this caliber is on the web. My references include those that can be found at:
    http://www.sixgunner.com/paco/Default.htm
    and other pages on that site.

    The usual advice applies - start low and work up a load that works for your gun and your situation.

    My basic assertion remains - you can't give the same advice for .45 Colt as you do for 30-06 with regard to staying within factory manual load data.
     
  24. Pistolsmith

    Pistolsmith Member

    Joined:
    Jan 4, 2003
    Messages:
    158
    Location:
    Pacific Northwest
    What about the powder manufacturer's information?
    The remarks are directed toward beginning handloaders, not those who have years of experience, as stated several times above.
    If your loads would damage older guns, how do you label your ammunition to insure that none of it will find its way into guns that would pose a destinct hazard? If unmarked, you would buy the liability, should it be fired in an older gun and an accident happens. This is a problem that needs to be addressed immediately. The 9X23 Win is another case inpoint, it would be lathal if fired in an old Spanish pistol chambered for largo. Is there a forumite who is a label printer? Perhaps we could give you some business and solve the problem.
     
  25. Archie

    Archie Member

    Joined:
    Dec 31, 2002
    Messages:
    1,925
    Location:
    Hastings, Nebraska - the Heartland!
    Another cautionary tale....

    Handgun calibers are usually loaded to a much lower pressure than rifle calibers. A slightly flattened primer in a .308 could indicate one should drop back 5 - 10 %. That same degree of flattening in a .38 Special means go to church this Sunday because its a miracle that revolver didn't come apart!

    The ladie's Beretta that always craters the primers is likely the result of an oversized firing pin hole. Not a guarantee, but if it happens with all factory stuff, it's likely. Still, 9x19 is a pretty stoutly loaded round in the first place; it is not for hotrodding.

    I have a .32-20 Savage rifle. I was trying some reloads in it, faithfully following the loading manual (I have several.) The starting load with 85 grain jacketed bullets made a *crack* noise instead of the usual -poof- sound. My chrono and pressure instruments indicated this was a maximal level loading.
    Remember what they keep saying in the loading books; every gun is different, test from the beginning? They are.

    On the other hand, I have an Improved .30-06. I worked up to a load I knew was on the top end... and shot it on a hot day. I won't give the exact load (I still have the data at home) but it threw a 200 grain Sierra SPBT at an average of 3271 f/s. Recoil was brisk, but not excessive and the bolt opened normally. No sticking, no nothing. Accuracy was real nice too.
    An older shooter pointed out where the primers were leaking around the edge of the pocket. And they de-capped real, real easy. But thanks to a 1917 Eddystone action and the Grace of God, I'm here to be embarrassed over it.

    Pressure instruments. Fabrique Scientific makes a fairly inexpensive pressure test meter. It will adapt onto most any firearm with a little finagling.
    That doodad and a chrono are the absolute best BS extractors I ever had for shooting. (Except for paper targets. Paper targets will take a lot of BS out of group size stories...)

    Pistolsmith. I have the series on "Firearm Pressure Factors" by Dr. Browning. You say that's not an accurate assessment of how interior ballistics works? Is there something better available? Do you know where I could read the opposing view or findings? Thanks.
     
Thread Status:
Not open for further replies.

Share This Page