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Posted By: FatAlbert CUP to PSI? - 01/10/20
How are you adj. CUP to PSI for QL?
Posted By: Ehryk Re: CUP to PSI? - 01/27/20
there is no conversion formula. The only thing you can do is find the actual PSI and enter those in for QL.
Posted By: Swifty52 Re: CUP to PSI? - 01/28/20
Originally Posted by FatAlbert
How are you adj. CUP to PSI for QL?


Originally Posted by Ehryk
there is no conversion formula. The only thing you can do is find the actual PSI and enter those in for QL.


Go here, answers some of OP’s question, debunks single answer.

https://www.shootingsoftware.com/ftp/psicuparticle2.pdf
Posted By: DonFischer Re: CUP to PSI? - 01/29/20
Why do you worry about it? Most likely you can't measure either and I'm guessing your gonna judge it with a chronograph? Doesn't make any difference what the pressure of a load is so long as the gun doesn't blow up and your getting results you like. If the gun is reaching 100,000 CUP or PSI either one and doesn't blow up but gives tiny groups, you gonna down load because of pressure you can't even measure in the first place?
Posted By: 5sdad Re: CUP to PSI? - 01/30/20
Originally Posted by DonFischer
Why do you worry about it? Most likely you can't measure either and I'm guessing your gonna judge it with a chronograph? Doesn't make any difference what the pressure of a load is so long as the gun doesn't blow up and your getting results you like. If the gun is reaching 100,000 CUP or PSI either one and doesn't blow up but gives tiny groups, you gonna down load because of pressure you can't even measure in the first place?


I believe that there is cumulative effect of excessive pressure that needs to be considered.
Posted By: DonFischer Re: CUP to PSI? - 02/03/20
Originally Posted by 5sdad
Originally Posted by DonFischer
Why do you worry about it? Most likely you can't measure either and I'm guessing your gonna judge it with a chronograph? Doesn't make any difference what the pressure of a load is so long as the gun doesn't blow up and your getting results you like. If the gun is reaching 100,000 CUP or PSI either one and doesn't blow up but gives tiny groups, you gonna down load because of pressure you can't even measure in the first place?


I believe that there is cumulative effect of excessive pressure that needs to be considered.


It the gun doesn't blow up, your good to go. Your worrying about something you have absolutely no way to measure!
Posted By: jwp475 Re: CUP to PSI? - 02/04/20


Denton Bramwell has a conversin formula that works well. Just google it and check it out
Posted By: Steve Redgwell Re: CUP to PSI? - 02/04/20
Overstressing the action is cumulative.

For QL, just follow their safe loads. Because the pressures are computer simulations, they will not match actual pressure measurements.

QL does not have a conversion formula built into it. To satisfy your own curiosity, the suggestion to use Denton's method will work.
Posted By: MickeyD Re: CUP to PSI? - 02/04/20
Originally Posted by DonFischer
Originally Posted by 5sdad
Originally Posted by DonFischer
Why do you worry about it? Most likely you can't measure either and I'm guessing your gonna judge it with a chronograph? Doesn't make any difference what the pressure of a load is so long as the gun doesn't blow up and your getting results you like. If the gun is reaching 100,000 CUP or PSI either one and doesn't blow up but gives tiny groups, you gonna down load because of pressure you can't even measure in the first place?


I believe that there is cumulative effect of excessive pressure that needs to be considered.


It the gun doesn't blow up, your good to go. Your worrying about something you have absolutely no way to measure!

If the gun doesn't blow up??? WTF?
This has got to be one of the most ignorant and dangerous comments I ever read!.
Einstein once said that there is no limit to the stupidity of mankind....further evidence that he was right.
Posted By: Henryseale Re: CUP to PSI? - 02/04/20
Someone, I THINK it was Ken Howell, once said in an article about reloading that he had a method that was pretty accurate in estimating pressure using chronograph info. Unfortunately, in the article he said that he would address this in a later article that he would publish at a future time. I do not know if he ever published it or not, as I have never seen it. I sure would like to learn about it. I can guess that maybe by taking a published pressure for a given load and comparing it to a published pressure of another load using the same powder, bullet, barrel, and primer and calculating the difference and then determining the amount of difference a grain of powder increase or decrease has on velocity, this could be converted to an estimated pressure for another load. ...Dang, that was a long sentence....I see a problem with this, if in fact this is what he had in mind - I'm only guessing. This does not take into consideration any pressure spikes a powder may have at different points. IF a particular powder is COMPLETELY CONSISTANT in equal increments with pressure increases with no spikes, I can see this as an accurate calculation. Again, I am only guessing what he was going to say. I would really like to know what he was going to say about this. If anyone has access to information about this, please post it. Thanks.
Posted By: FatAlbert Re: CUP to PSI? - 02/04/20
MickyD: I think that we just discovered another person that you would not have at the shooting bench next to the one that you are using. PS : how I do it is make a correlation between the two numbers. On a 223 Rem the max # are 55.0K PSI and 52.0K CUP. I dev. the 55.0 by 52.0 and get 1.0577. To get PSI from CUP, I mult. the CUP by 1.0577. To go from PSI to CUP, the # is 0.9455. So PSI X 0.9455 = CUP? or there about .
Posted By: BufordBoone Re: CUP to PSI? - 02/05/20
I've conducted a lot of Piezo pressure measurements. I've also conducted a lot of velocity measurements.

Prior to conducting Piezo pressure measurements, I had a favorite load that was MUCH faster than the reloading manuals.

The evening that I conducted Piezo pressure measurements on Proof loads I went home and pulled the bullets from my favorite loads.

The reality is that (assuming reasonable propellants) Velocity = Pressure. If you are getting way higher velocity, you are getting way higher pressure.

Blowing up a gun when you are planning it and recording the results can be fun. Blowing up a gun when you are holding it is not.

If you care about your safety, get a good chronograph and load reasonable components to reasonable velocity.
Posted By: Borchardt Re: CUP to PSI? - 02/05/20
Originally Posted by BufordBoone
I've conducted a lot of Piezo pressure measurements. I've also conducted a lot of velocity measurements.

Prior to conducting Piezo pressure measurements, I had a favorite load that was MUCH faster than the reloading manuals.

The evening that I conducted Piezo pressure measurements on Proof loads I went home and pulled the bullets from my favorite loads.

The reality is that (assuming reasonable propellants) Velocity = Pressure. If you are getting way higher velocity, you are getting way higher pressure.

Blowing up a gun when you are planning it and recording the results can be fun. Blowing up a gun when you are holding it is not.

If you care about your safety, get a good chronograph and load reasonable components to reasonable velocity.


Truer words were never spoken when it comes to hand loading ammunition.
Posted By: mathman Re: CUP to PSI? - 02/05/20
Originally Posted by FatAlbert
MickyD: I think that we just discovered another person that you would not have at the shooting bench next to the one that you are using. PS : how I do it is make a correlation between the two numbers. On a 223 Rem the max # are 55.0K PSI and 52.0K CUP. I dev. the 55.0 by 52.0 and get 1.0577. To get PSI from CUP, I mult. the CUP by 1.0577. To go from PSI to CUP, the # is 0.9455. So PSI X 0.9455 = CUP? or there about .


You need to read Denton's article.
Posted By: BushCaddy Re: CUP to PSI? - 12/19/20
Originally Posted by mathman
[quote=FatAlbert]MickyD: I think that we just discovered another person that you would not have at the shooting bench next to the one that you are using. PS : how I do it is make a correlation between the two numbers. On a 223 Rem the max # are 55.0K PSI and 52.0K CUP. I dev. the 55.0 by 52.0 and get 1.0577. To get PSI from CUP, I mult. the CUP by 1.0577. To go from PSI to CUP, the # is 0.9455. So PSI X 0.9455 = CUP? or there about .


You need to read Denton's article.[/quo

Here's another one that will get you into the ball park.. ball park only !
..not the Game.

1.516 X CUP minus 17,902
Posted By: BushCaddy Re: CUP to PSI? - 12/19/20
For those with Quickload who may not know.. you can adjust the burn rate of a particular powder/lot by simply tweaking the burn rate to coincide with the measured 5 shot average chronograph velocities from a particular rifle and cartridge. Be sure to tweak the ambient temperature setting as well . File the resulting burn rate/temp and bullet weight data in QL or in your log book. I've found burn rate/pressures to be quite consistent, but you have to enter Ba each time as QL reverts to default values after each use, .
Posted By: kwg020 Re: CUP to PSI? - 12/27/20
SAAMI does have a conversion formula CUP to PSI is CUP x 1.52 - 18,000 = PSI
Posted By: SheriffJoe Re: CUP to PSI? - 12/27/20
Originally Posted by DonFischer
Why do you worry about it? Most likely you can't measure either and I'm guessing your gonna judge it with a chronograph? Doesn't make any difference what the pressure of a load is so long as the gun doesn't blow up and your getting results you like. If the gun is reaching 100,000 CUP or PSI either one and doesn't blow up but gives tiny groups, you gonna down load because of pressure you can't even measure in the first place?




Anytime you get to the 100,000 CUP...wear eye protection.
Posted By: AU338MAG Re: CUP to PSI? - 01/01/21
Originally Posted by SheriffJoe
Originally Posted by DonFischer
Why do you worry about it? Most likely you can't measure either and I'm guessing your gonna judge it with a chronograph? Doesn't make any difference what the pressure of a load is so long as the gun doesn't blow up and your getting results you like. If the gun is reaching 100,000 CUP or PSI either one and doesn't blow up but gives tiny groups, you gonna down load because of pressure you can't even measure in the first place?




Anytime you get to the 100,000 CUP...wear eye protection.

And body armor.
Posted By: 1minute Re: CUP to PSI? - 01/08/21
With 30 seconds of surfing one can find several conversion formulas. Notice, however, almost no one ever includes their correlation coefficients or coefficients of determination (R or R²) which are indices of exactly how well the various values match up.
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