One post says that you can approach 3200 fps in a 300 Win Mag case with a 180-grain bullet -- which can only be done by greatly exceeding the manual maximums. Another says that manual maximums should NEVER be exceeded, which means that I'll flounder around 2950 fps with my 300 forever.

This doesn't take into account the trememdous differeces in loads published in different manuals (ie. Hodgdon says the Max 180-grain load in a 300 with H4831 is 73 grains. Lyman says it's 76 grains. Both manuals list about the same velocities with their maximums.)

I'm not really complaining or asking for a response, just carping about not being able to put my finger on "absolutes" when I reload.

When reloading, follow the loading tables. If you have a chronograph and plenty of reloading experience, you can in some circumstances exceed maximum load tables. This is not blindly recommended. The maximums are there for a reason. Excessive chamber pressures can be accumulative. It may not get you the first time or the one hundredth time, but metal fatigue is a real phenomenon. Chamber failures can and do happen.

A chronograph and careful inspection of your fired brass can tell you a lot about your loads. I will say that the animal you are shooting will not know the difference between 2900fps and 3200fps. Your bullets will not magically find the target with another 100 to 200fps behind it. Most of the time, your best accuracy is achieved below maximum pressures, so pushing bullets is not the best solution.

There is a lot of wisdom on this site and there is a lot of experience on this site and then there are the opinions on this site. I would be careful of the opinions....

GAHUNTER....the secret to getting higher velocity when reloading is to use a bigger case....if you want more velocity out of your .30 caliber than you WinMag can give you, move up to a Weatherby or UltraMag or whatever. Trying for the last few fps is a losing proposition...it's hard on the brass and the least little glitch in seating etc can give you a pressure spike you won't like.
After all the energy difference between a 180gr bullet doing 3000fps and 3100 fps is only is only 240 ftlbs.

quote:

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Originally posted by Zero Drift:
.....When reloading, follow the loading tables. If you have a chronograph and plenty of reloading experience, you can in some circumstances exceed maximum load tables. This is not blindly recommended. The maximums are there for a reason. Excessive chamber pressures can be accumulative. It may not get you the first time or the one hundredth time, but metal fatigue is a real phenomenon. Chamber failures can and do happen.....

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Hey GAHUNTER, Looks like I'm going to have to agree with that portion of ZD's post. He's right on the nose with it.

I also understand the high regard some folks have for using a chronograph to "assist" in understanding what is happening in a Load. Only problem is, it can be misleading depending on the barrel and Load used. But it is much better than nothing.

I'd encourage you to learn about Case Head and Pressure Ring Expansion which tell you what the "weakest link" in the firing sequence(the case) is experiencing. It works on every cartridge made and has been used ever since self-contained Loads came into existance. Plus it only costs $25 or so for a 0.0001" capable set of Micrometers.

The fundamentals are rather simple. You need a box of factory ammo to use as your Benchmark Standard. And you measure the "Expansion" to 0.0001" (0.001" is not accurate enough) with Micrometers. Reload those same factory cases and once you reach the same amount of expansion with "a Specific Lot" of Primers, Powder and Bullets - STOP!

Now, there are a few tricks to it and it does take a bit of time to do the measurements properly. But, that's just the way it works. I never am in a big hurry when I'm testing new Loads, so it doesn't matter to me at all. Plus it allows the barrel to cool a bit between shots while I'm doing the measurements.

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Good hunting and clean 1-shot kills, Hot Core

Look at all the variables...

Barrel (length, width, bore, type of rifling)
Chamber (over?/under?, short?/long?)
Hundreds of different powders which vary from lot to lot.
Hundreds of different bullets which vary from lot to lot.
Scores of primers which vary from lot to lot.

Then there is temperature, wind, barometric pressure, angle of departure...

Oh...and finally the frame of mind of the reloader/shooter.....

Unfortunately, the bullet manufacturers themselves add to the confusion by not telling you which of the bullets their data are based on.

Nonetheless, if you limit your comparisons to loads using the same powder and the same bullets, the differences are much less dramatic.

I recently made up some tables for cartridges I reload, showing multiple loads using the same powder for the same bullet. (E.g., .30-06, 165-gr. Hornady SP with IMR-4350.) If you look up the same bullet in the bullet maker's manual, the powder maker's manual, and books like Ken Waters' "Pet Loads" you will find that the difference between listed maximums is only a grain or two.

BTW, for the loads I looked at, Waters' loads marked as "maximum" (based on pressure ring expansion measurements) are usually, if anything, a little lower than the ones in the manuals.

John

quote:

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Originally posted by GAHUNTER:
One post says you should be aware and look for signs of over-pressure. Another says that over-pressure signs are not reliable and over-pressure is achieved most of the time with no signs.

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Part of the problem is understanding what the weak point is which will fail at excess pressure.

Most of the people on this forum are devoted to bolt action rifles such as the rem 700. This is claimed to be a very strong action and in most calibers the failure will be the brass. As such, monitoring the brass should show if pressures are causeing the brass to give beyond the safe point.

Other actions may be weaker or stronger. Some calibers such as 45-70 are chambered in some weak and some strong actions. The brass may not be the weak link in some of these actions. So what can we use to gauge pressure if the brass is stronger than the action? In my .256 win mag in my ruger hawkeye, I felt the top strap was springing and letting the brass stretch enough that the action would open hard. Right? or Wrong? Safe?

Further, I thought guns were proof tested but to what pressure? A 30-30 won't be tested to the same level as a 30-06, or will it? If we exceed or even run close to proof test loads how can we know we any safety margin left?

I expect some of us will keep pressures down to extend barrel life. Certainly running 70,000 to 80,000 psi in a varmint rifle will shorten the life of the throat compared to 50,000 psi. Understand that a rem 700 in something with a small case head like a .223 will have far less stress than the same action with a large case head like the RUM, while haveing far more steel around the case to hold the stress. I won't worry about the strength of the steel in a rem 700 with a .223 or even a .30-06, but in a RUM I would have to wonder.

Of course, pistols have their own weak points. Look at the thickness of the steel around the cylinder of a S&W J-frame .357 and decide how far you would want to push it. Or read the stories of KB's in some auto pistols.

What a lot of words just to say that pressure signs are mostly for STRONG actions like bolt action and falling block rifles.

JerryO

http://www.serveroptions.com/ubb/Forum6/HTML/003015.html

One reference in JerryO's post caught my eye. 70-80000 psi. For a couple reasons this is very unlikely. Stan Watson who posts as OKShooter sez most all primers give way at 72-73000- piercing that is. This is one fella I believe and listen to. And- those supposed pressures are awful hard on brass and tend to expose the gun's flaws. Lugs uneven, barrel roughish- it'll foul more that those pressures and you might actually start obturating some of those varmint bullets- which will shot like hell. Just no reason for a fella with a drop of sense to operate there.

I let the gun tell me where it wants to run. A combination of brass life and pocket feel, how the gun groups-- just to find that sweet spot. It might be a max and it might not be. But it's gotta be accurate.

Mike

I have a standard anvil 0.0001" capable Mitutoya(sp?) Micrometer that I got from an Instrument Company in Louisville for $35, years ago. And I found a set of "Thin Blade" micrometers in a Pawn Shop(normally $165) that I got for $25, 10 or so years ago.

For everyone else reading this thread, I see mention of OKShooter who typically quotes pressure figures based on a few hundred shots through 3 rifles using an Oehler M43 as his pressure indicator. He used to quote actual Loads that approached 100,000psi and I called him on it numerous times over at Shooters. So, though I'm glad to see that ignorance has stopped, I'd encourage you all to stick with data provided by "the actual Component Manufacturers", or what you see in your own firearms.

The Component Manufacturers data is developed over hundred of firearms with hundreds of thousands of shots expended. Comparing their data to any single person's data is just not in the same league.

One additional problem with the M43 is the "Calibration Procedure" using an "unknown" value to set the instrument. If you are thinking of buying one, I'd encourage you to buy a M43 Owners Manual and read the Calibration Section, see how it says to do it and then think about it.

That said, it is still a nice instrument for a Lab environment, but I would never put a Strain Guage on one of my barrels in order to get "Second Hand" information. But that is just me. If you do get one, all the bast to you.

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Good hunting and clean 1-shot kills, Hot Core

Then again in the olden days when the copper crushed ruled, you'd hear of lab tech's forgetting to calibrate their new crusher ball reading with the data currently produced. Each lot # was a different hardness to be accounted for. And the new equippment has it's bugs too. In the end, there's some slack in each system.

quote:

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but I would never put a Strain Guage on one of my barrels in order to get "Second Hand" information.

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Gee, I guess all the time I spent in the materials lab at school I was being graded on "second hand information." Ever fly? The airplanes in which you fly are certified as safe by the FAA using this "second hand information." Even worse, most of it isn't even "second hand information" but "third hand educated guesses."

Explain to me how you would design a guage that wasn't "second hand information."

Information from a strain guage is no more "second hand information" than any other method. The only difference is that any method you want to put on your pride and joy without butchering it can't be calibrated absolutely. That doesn't mean that the relative readings are anything but as accurate as can be.

For absolute readings, any instrument needs to be calibrated. But whether your strain guage system reads 2000 psi high or low doesn't really matter because it will read consistantly. For instance, if you get an ejector mark at a reading of 69,000 psi, you know that any load that shows 65,000 is 4000 below the pressure of the first load.

That's useful information. Case head expansion? Do you know the tolerance of the web thickness at the head of the brass you're using? Think it won't make a difference? That's sounds more like "4th hand information" to me.

quote:

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Originally posted by aladin:
Hot Core: Stan's figures since I've followed his postings are mostly right in line with component manufacturers. He offers some unique perspectives not usually discussed around reloading circles.

....And the new equippment has it's bugs too. In the end, there's some slack in each system.

---

Hey aladin, Real glad it finally sunk through his skull that posting those 100,000psi Loads could possibly hurt someone. I would have bet, that he never would understand it. I can remember his insane argument that, "If people don't know not to load-up those 100,000psi Loads, then they shouldn't be reloading!" I just can't see where anyone with even half a lick of sense would not understand how posting ANY Loads like that was/is wrong.

So, always be on guard (regardless of the source of information) and maintain your own counsel.

I agree completely with your assessments about each method having some bugs, slack or quirks.

So as not to mislead anyone, I personally disagree with many of Stanley's "unique perspectives". Watch your results as you continue reloading and at some point you might just see through those "unique perspectives".

Hey Jon A, If you like the M43, I'm all for you. I do stand by my original post however, since it is TOTALLY 100% CORRECT. HAHAHA

I agree that "some" of the information gathered in the Material Labs was indeed 2nd or 3rd hand info, but that really adds nothing but clutter to this specific discussion since it is irrelevant. Same with info from airplanes.

Jon A: Explain to me how you would design a guage that wasn't "second hand information."

Hot Core: Glad you asked since there is no need to design one at all. The good old 0.0001" capable Micrometer will provide "1st Hand info" directly from the Case, which is the Weakest Link in the firing process - not the chamber. (I feel sure you understand that.)

Jon A: But whether your strain guage system reads 2000 psi high or low doesn't really matter because it will read consistantly. For instance, if you get an ejector mark at a reading of 69,000 psi, you know that any load that shows 65,000 is 4000 below the pressure of the first load.

That's useful information.

Hot Core: Maybe it is and maybe it isn't useful information. It is REALLY dependant on the actual composition of the cases being used and just how far-off the Calibration "actually is". Now, if you take a bit of time and read the Calibration procedure for the M43(as I previously mentioned), then you will see it is only a "guess" as to what the REAL Pressure is. So, that creates false confidence that everything is OK, when it might or might not be.

The real problem as I see it, is that once you beging seeing those XX,000psi values listed, you might just begin to believe they are infalable. Of course that is based on the false premice that you got the M43 Calibrated "accurately". Then you have people begin quoting (for Rookies to see) those values(like Stanley) as if they were gospel, and that just isn't true.

JA:Case head expansion? HC: Yes!

JA: Do you know the tolerance of the web thickness at the head of the brass you're using? HC: No.

JA: Think it won't make a difference? HC: Since you are using the "factory loaded cases" to establish your Benchmark Standard " AND " you use those same cases to compare your Development Loads in, you are correct in that it will not make a difference. It is unnecessary information when using the Case Expansion Method.

JA: That's sounds more like "4th hand information" to me. HC: Think about it with an "Open-Mind" and it will become clear to you since you've apparently had Material Lab courses.

If you want "First Hand" data from the most critical component, then you simply need to analize what is happening to the Case. If that does not make sense to you, then I can understand why you "seem" to disagree with my first post.

Sure is nice that you can get 1st Hand, accurate, SAFE and repeatable Pressure information with only needing to spend $25 and a bit of time reading the case Expansion values though. AND, not have to screw-up the barrel by sticking a Strain Gauge on it.

And Jon A, seriously, best of luck to you when using which ever methods you choose. Merry Christmas to you and your family. And if you are using a M43 to develop your Loads, might I suggest giving your "Honey" a BIG Insurance Policy on yourself!!! HAHAHA

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Good hunting and clean 1-shot kills, Hot Core

Go to Stan's website today- it's well done and presented so the vast majority can come away with something learned- of value to their reloading education.

<<And if you are using a M43 to develop your Loads, might I suggest giving your "Honey" a BIG Insurance Policy on yourself!!! HAHAHA>>

Now the above is not in line with the spirit of these forums. One thing that's holding around the Accurate Forum is for the most part a lack of this kind of verbal trash. Guys disagree on points- the exchgs get a little emmotional-- then this schoolboy tit for tat starts. I mean- who cares? This hobby is supposed to be recreation- hey right?

I happen to agree with you that mic readings are of merit. Certainly not a predictor of exact pressures, but a tool to find a safe load within the confines of that lot # of brass in said gun. I'll give you an idea for an interesting experiment- least from my pt of view. Have a group of cases your working with precisely measured for hardness- and as there used. Find your load predicting pressure levels, then send some samples out to say Alliant. They'll pressure check those loads for free if their Alliant powder. Maybe the other powder co's will too- I dunno. Be a real interesting correlation between all those factors..

quote:

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Originally posted by Hot Core:
And if you are using a M43 to develop your Loads, might I suggest giving your "Honey" a BIG Insurance Policy on yourself!!! HAHAHA

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As I'm pretty sure that was a joke, let's dispense with it anyway as there are inexperienced people reading this that might get the wrong impression.

To imply that anybody that is into this hobby enough to spend $800 on a tool to aid in the reloading process would be dumb enough to ignore obvious, visual pressure signs and continue to add more powder simply because "the machine says I can" to the point he "blow himself up" is absurd and counter productive to this discussion.

Whatever tool or "system" one uses, simply being careful and using common sense should be more than enough to keep him from "blowing himself up."

There are a multitude of reasons a strain guage is going to be more accurate than measuring case head expansion. Let's discuss some:

First, consider that the same case can have a different amount of expansion with the exact same load (which should give nearly identical chamber pressures) when new, once fired, twice fired, etc--it's up to you to "calibrate" this and try to make some sort of sense out of it. A strain guage would read the same chamber pressure every time.

Different kinds of brass, lot numbers, etc will show different amounts of expansion for the same pressure. Consider a case with a rather thick web of material at the head--it will show the same amount of expansion at a higher pressure. Some would argue that's OK because the case is the weak link. That's true if you look at it one way but not another.

If one kind of brass will last 10 loadings but another shows loose primer pockets after 7 and needs to be tossed at the same pressure, that doesn't mean to me that the "tough" cases are safe at higher pressures. I'm more interested in the margin of safety of my rifle's action. If I actually measure that a certain load puts more stress on my action than I have deemed maximum, I'm going to back off. I don't care if the "tough brass" handles it OK. It's reducing the margin of safety of the action itself causing the chamber, recoil lugs, etc to flex more. A strain guage is the only way to measure that. Having to throw your brass away after 3 or 4 loadings instead of 7 or 8 never blew anybody up (no matter how long the cases last, they should always be properly inspected before reuse). Increasing the fatigue on your recoil lugs, etc, because the "tough brass" handles higher chamber pressures OK not something I agree with.

Finally there is the way the material itself reacts to different stresses. Have you ever seen a stress/strain curve? For most metals known to man, there is a nice linear relationship between stress and strain (a straight line) for elastic deformation--the material returns to its original shape once the stress has been removed. For a given amount of stress, you'll have a given amount of strain. Consistant and predictable. That's what a strain guage measures.

Once you exceed the yeild limit of the material and go into plastic deformation, the relationship is no longer linear. By measuring how much the material was deformed plastically you cannot accurately determine how much stress the material has been subjected to. If you compare it to the copper crusher method--although much different--consider that each lot of copper material is measured and calibrated against a known standard to determine how much the copper will crush for a certain amount of pressure. And do they use the same chunk of copper twice? Do you know how the material properties of your case changes after being cold worked a certain number of times?

At anything close to safe pressure levels, you aren't going to change the material properties of your chamber. A certain amount of strain equals a certain amount of pressure acting on the rifle's chamber. Always.

Once you determine a maximum amount of strain (using various "calibration methods"--as you must using head expansion as well--and of course using much common sense, etc) you want to subject your action to, you'll be able to quickly easily and accurately work up new loads to that exact pressure.

As long as you stick to that amount of strain you'll be keeping the same margin of safety for your rifle's action. Exactly the same, every time, regardless of what brand of brass you're using or how many times it has been loaded (using "common sense" should obviously help you choose a limit that is well below the point that any brand of brass would have any visual pressure signs). It will be a hell of alot less time consuming than measuring cases (and "calibrating" for different case lot #'s, etc) as well.

Oh, and the fact that SAAMI has accepted the strain guage method as a valid means of measuring chamber pressure might mean a little something. When they do the same for case head expansion, let me know.

BTW, I'm not considering the Model 43. It sure would be nice but my pockets aren't that deep. I am seriously considering the $150 unit mentioned in the other thread. Like I said, it would simply be a very valuable tool for reloading. One that a $25 caliper couldn't match (I already have one of those anyway).

Also, I don't see how gluing a strain guage onto the bottom of the chamber (where it can only be seen when the action is removed from the stock) is in any way "messing up" the rifle. If you use the right glue it could be removed with no damage to the rifle anyway.

Been fun,

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Gerard Schultz
GS Custom Bullets

www.wideners.com (800)615-3006

The also have an RCBS Digital Micrometer for $35 - Item# RC87322.

Also noticed that Lyman(page 47) is offering a Vernier style for $20.50 - Item# 7832230. And a Digital Micrometer for $41 - Item# 7832234.

I was surprised at the low cost myself. However, I've not had a set of them in my hands, so I don't know how well they are made.

Hey aladin, Yes, the "HAHAHA" on the end was intended to indicate I considered that a joke. And I do consider "humor" a worthwhile part of this Forum. I certainly did not intend it as "mean spirited" or "verbal trash". When I do intend something as "mean spirited", there is NEVER any doubt.

aladin: This hobby is supposed to be recreation- hey right? HC: I agree with you once again.

Stanley has absolutely "nothing" at his site that I'm interested in. It gets back to the limited number of rifles and the limited number of shots through them. The Data Base is just not large enough to be Statistically Relevent, let alone offer that stuff as an alledged Manual.

Let me give you an example of why I consider it "Irresponsible" to use that information. At one time I had a 7mmRemMag that would easily take X6gr of a specific Powder with a specific 150gr Bullet. Probably fired 800-1000 of them through that rifle and it loved the load. The last two bullets I put through that rifle overlapped and then I sold it to a friend's nephew who was with me at the Range. X8gr was absolute MAX in it.

Got my next 7mmRemMag and X2gr of the same Powder with the same Bullet was absolute MAX. Even 1.0gr more got to the Sticky Bolt level.

Now, I know why the first rifle would take more powder, because of the bore/grove dimensions. Funny thing is that every rifle I ever owned from that particular manufacturer(prior to them implementing a major design change) ALWAYS had bore/groove dimensions "larger" than all other manufacturers.

That resulted in "lower pressure" with standard Loads, but "fast" because of less resistance. You could easily load those rifles with more Powder SAFELY and get excellent velocity and accuracy.

So, if I gave someone Loads from the first rifle, depending on the rifle that person had, chances are it would be an "overload".

With the information provided by the Component Manufacturers, the Data Base is large enough to be Statistically Relevant and in "most" instances will be SAFE in whatever rifle you put them in. Some still might be a bit hot and some not hot enough. That is why they should only be used as "Guidelines" and a person should ALWAYS Develop their own Loads for a specific set of components in a specific firearm.

So no, I'm just not interested in what Stanley is trying to get people to buy.

I also understand what you are saying about sending a Load to Alliant to test, but from the example above, you should be able to see the problem with that. A nice SAFE Load for that first 7mmRemMag is probably going to show up as a serious Over-Load in their Pressure barrel. The only thing it will tell you is how that Load performs "in their barrel".

Hey Jon A, Is there ANY CHANCE at all that you've NEVER tried the Case Head and Pressure Ring Expansion methods?

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Good hunting and clean 1-shot kills, Hot Core

The value of the extra speed is not so much in the power gained but in the added ease of hitting the right spot. The 210 gr bullet I had in mind was a partition from a 340 Weatherby but only by way of example......

An animal that takes off at the same instant that you break the shot will easily move 8" in .04 sec and that, plus increased wind drift on the slower bullet equates to a larger possibility of messing up. I prefer not to deal with handicaps like that, I am too slow as it is.

If you want real performance from your 300WM, use a 160 gr bullet at 3450 fps. More momentum and energy than 200 gr bullets and less wind drift, quicker time of flight and a flatter trajectory. It makes precise shot placement much easier and that is what counts.

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Gerard Schultz
GS Custom Bullets

I didn't abandon it because it was of no value, it was simply so time consuming for the accuracy it gave as well as some of the limitations mentioned above (you can't work up a new load with new cases without first loading a bunch of them with a known load to give a baseline, then after they've been fired once...etc). It simply didn't seem worth the effort.

I found the use of a chronograph, intimate knowledge of what the cartridge "should" be capable of with different bullet weights along plain old common sense (looking for visual pressure signs, reduction in the increase of velocity with an increase of powder, etc) would get me to the same place with a whole lot smaller PITA factor. Maybe not quite as accurate but good enough if you use your head. I had also just read an article on the Oehler and figured when I wanted to be really accurate I'd just get something like that.

Best of luck to you as you go forward in testing new Loads with your M43.

Merry Christmas!

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Good hunting and clean 1-shot kills, Hot Core