Anyone try Pressure Trace????

If used properly a strain guage setup like the oehler 43 can quite accurately measure chamber pressures.On the other hand a chronograph measures only velocity which can't be directly converted to chamber pressure.
 
I don't know if they are stillin business. I bought one last year as well as a kit with 6 extra strain gages. Haven't gotten around to playing with it yet t, though!
 
stubblejumper said:
If used properly a strain guage setup like the oehler 43 can quite accurately measure chamber pressures.On the other hand a chronograph measures only velocity which can't be directly converted to chamber pressure.
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The powder companies have already done all the pressure testing for you. With a crony, you can compare your velocity and powder charges to those published and will have a very good idea of pressure.
Besides, velocity is primarily what you are interested in when loading anyway. You want a powder that will fill that case and give you the desired velocity at normal operating pressures for the given cartridge. You can get all that info free online....no need for expensive pressure testing guages.
Just my 2 cents.:eek:
 
The powder companies have already done all the pressure testing for you.
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The people publishing load data have measured pressures and velocities in their rifles not yours.The same pressure can produce different velocities in different rifles even with identical barrel lengths.That is the reason that the same load in the same length barrel can list the same pressure but different velocities in different loading manuals.
 
Besides the fact that I am working outside the normal realms and published data. I figure a pressure strain guage is needed to play it safe.

As far as that goes you can never gather too much information.....
 
stubblejumper said:
The people publishing load data have measured pressures and velocities in their rifles not yours.The same pressure can produce different velocities in different rifles even with identical barrel lengths.That is the reason that the same load in the same length barrel can list the same pressure but different velocities in different loading manuals.
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Of course, I didn't say you could determine the exact pressure, just get a good idea, probably within 5000psi or so. If you use the exact same loads in the same barrel length as published data, and find your velocity short, then it's safe to assume you are under the published pressure. Same if your velocity is over but the charge is the same, you are probably over the published pressure. When I work up a load, my goal is a certain velocity. I look for the powder that will give me that published velocity with a slightly compressed charged (optimum burning speed), with published pressure within spec for the cartridge and rifle I'm using. If the velocity I want is higher than published, then I need to move up to a larger cartridge. I would not use a pressure guage to try and justify overcharging published max loads.
This is the method I have always used and never had any problems.
 
If you use the exact same loads in the same barrel length as published data, and find your velocity short, then it's safe to assume you are under the published pressure. Same if your velocity is over but the charge is the same, you are probably over the published pressure.
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Again you are assuming that a given pressure will always produce the same velocity in every barrel of the same length.That is an assumption that simply is not true.Just because your velocity is below the velocity in the manual,you can't be sure that you are developing less pressure.

I would not use a pressure guage to try and justify overcharging published max loads.
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A properly used strain guage setup will accurately measure chamber pressure in your gun,whereas comparing your actual velocity against those listed in loading manuals will not.How do you suppose the people producing loading manuals measure the chamber pressures in psi?That maximum load published in the loading manual is only accurate for the gun that it was developed in.Due to variances in chamber and barrel dimensions the load that produces the maximum safe pressure in your gun may be a few grains more or less than the charge that produces the maximum safe chamber pressure in the gun used by the people publishing the loading manual.Why do you suppose that the maximum velocities produced by a certain load often varies by well over 100fps from manual to manual even though they all supposedly load to the same chamber pressure for a given cartridge?
 
stubblejumper said:
Again you are assuming that a given pressure will always produce the same velocity in every barrel of the same length.That is an assumption that simply is not true.Just because your velocity is below the velocity in the manual,you can't be sure that you are developing less pressure.



A properly used strain guage setup will accurately measure chamber pressure in your gun,whereas comparing your actual velocity against those listed in loading manuals will not.How do you suppose the people producing loading manuals measure the chamber pressures in psi?That maximum load published in the loading manual is only accurate for the gun that it was developed in.Due to variances in chamber and barrel dimensions the load that produces the maximum safe pressure in your gun may be a few grains more or less than the charge that produces the maximum safe chamber pressure in the gun used by the people publishing the loading manual.Why do you suppose that the maximum velocities produced by a certain load often varies by well over 100fps from manual to manual even though they all supposedly load to the same chamber pressure for a given cartridge?
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I think pressure has a direct effect on velocity when you are talking about the same speed of powder---higher pressure = more velocity. Take a military .5.56 case and a winchester or other commercial case and load them with the same charge. I've found a 100fps+ gain from the use of military .223 brass. Same powder charge, same bullets, fired out of the same rifle, but the pressure is higher with the thicker military brass due to reduced capacity, end result is higher velocity. Did I need a pressure guage to figure that out?
I agree that there are variances from rifle to rifle, and from published test barrel data to the real thing, I'm not saying velocity will give you the exact published chamber pressure.
I'm saying if velocity is the same as published data using the same components, in the same barrel length, pressure is very close to published that it doesn't warrant individual pressure testing equipment.
I think a pressure guage would be a neat toy, I just don't think it's necessary or even important to the average handloader when there are dozens of bullet and powder companies that have already done the work for you.
 
Same powder charge, same bullets, fired out of the same rifle, but the pressure is higher with the thicker military brass due to reduced capacity, end result is higher velocity. Did I need a pressure guage to figure that out?
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The key factor being "fired out of the same rifle,".That is not the case when using data from a loading manual.Your rifle is not their rifle.
 
Missing Something said:
Besides the fact that I am working outside the normal realms and published data. I figure a pressure strain guage is needed to play it safe.

As far as that goes you can never gather too much information.....
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Again I will state that it is an additional tool in the reloaders tool box. It's nice to be able to use reloading manuals but that doesn't always mean reliable data... there is a fair bit of differences between manuals and maximums.

Read line 1.
 
stubblejumper said:
The key factor being "fired out of the same rifle,".That is not the case when using data from a loading manual.Your rifle is not their rifle.
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That comparision was the counter arguement to you saying that pressure doesn't have a direct effect on velocity, it does.

Again you are assuming that a given pressure will always produce the same velocity in every barrel of the same length.That is an assumption that simply is not true.Just because your velocity is below the velocity in the manual,you can't be sure that you are developing less pressure.
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I think if you are steadily pushing the limits on all your loads then a pressure guage might be worth while, but I doubt you will find much difference from all the published data out there.
 
More tools have got to be better, however as long as you're working up from below and useing good case life (tight primer pockets) as a guide you shouldn't go too far wrong.If you're working at max first time out and loading at the range I find measureing the case head to be a fairly effective if a little crude way to stay safe. I'm just too cheap, a gauge would no doubt be very interesting.
 
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I think you need a load that produces a known pressure to calibrate the unit. You could use factory loads but realy you don't know exactly what pressure they are making in your rifle. So in the end you are only going to measusure as accurately as your inital calibration, which could be way off. This is the weakness of the pressure trace system.
 
Missing Something said:
Besides the fact that I am working outside the normal realms and published data. I figure a pressure strain guage is needed to play it safe.

As far as that goes you can never gather too much information.....
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Does line one refer to 14.5x114mm Russian AT rounds? I can't seem to find any info for that one in any of my Nosler, Speer, etc. manuals.:D

Stay in touch. I am interested to learn from your testing.
 
I have not been reloading for long. But the relationship between pressure and velocity is not unique. There are multiple variables to consider.

1. Bullet seating
2. Primer
3. case
4. Temperature

Yes I run published loads, but in order to further tweak the loads, a pressure gage would be an excellent addition IMHO
 
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