QL and why or GRT

Both are fine tools. But they remind me of static AM channels that need a fine dial to tune and hope clouds or other environments don't interrupt the frequency at just the wrong time.

Know your end goals and if the tools aren't working go back to what's others were doing turn of the century. Aka talk to the powder makers, caliber designers, barrel spinners, case designers with your list of practical questions.
 
So WHERE in the GRT interface do you enter the primer choice? I have not found that. Powder, yes. Bullet, yes. Primer, NO.

WHERE???
In the projectile window (GRT) you can select caliber type, projectile type and primer type (standar vs magnum) and it will adjust the initial pressure. Or you can adjust the initial pressure yourself.
You can also adjust initial pressure in QL.
 
I know about QL and its default value for start pressure...same for GRT. Those are just SWAG values, in reality (but you gotta have something). If we really knew all these values we could probably make the program work really well.

I see NO field for primer choice in GRT. I also checked for updates and I have the latest version of GRT.

And YES, I understand that start pressure will be affected by numerous things including the primer used. That's a given. To quantify start pressure with any precision is a different story.
 
I know about QL and its default value for start pressure...same for GRT. Those are just SWAG values, in reality (but you gotta have something). If we really knew all these values we could probably make the program work really well.

I see NO field for primer choice in GRT. I also checked for updates and I have the latest version of GRT.

And YES, I understand that start pressure will be affected by numerous things including the primer used. That's a given. To quantify start pressure with any precision is a different story.
when you click on the "star" by the initial pressure, you will get the folowing screen. Initial pressure will be adjusted according to your choices.
1673798158955.png
 
Thank you.

I didn't realize that clicking on the stars did anything at all...I thought they were there to draw attention to the fact that the corresponding field could be edited. More stuff to pay with!

Thanks again.
 
I agree. Internal ballistics is a universe unto itself.

When I fist experienced QL I spent many, many hours just playing round with various inputs to see how they affected the solution. GRT offers even more to fiddle with. I hope it survives and flourishes. There are holes in the component databases that need to be filled, but if that ever takes place it's going to be a formidable tool.
 
If you calibrate QL using a calculated weighting factor and adjust BA to set the velocity to your measured velocity, it will spit out a barrel time within 1.5% of matching the barrel times in the calculated tables. This works every time for bottle neck cartridges with a weighting factor less than 0.7 for me. GRT, on the other hand, has not ever provided me with a correct barrel time. Your mileage may vary.
 
DC just proved it didn't know everything! At least some on this thread is giving info that could be useful in the end!
 
That's part of the "why and how" should you use or change that input on which primer is being used?

DC just proved it didn't know everything! At least some on this thread is giving info that could be useful in the end!


I never said I know everything. Your answer was irrelevant to the question at hand whether or not I was aware of the option to select a magnum primer because either way you get a default value for start pressure which is at best a SWAG, and distance to the lands (which you cannot precisely account for in the software) is the one thing you CAN influence by how deeply you seat...the problem becoming you cannot effectively estimate the correct start pressure value any way you slice it. Either default value most certainly not correct in any case.

Now go away...you've proven that you're every bit as useful as a housefly.
 
I never said I know everything. Your answer was irrelevant to the question at hand whether or not I was aware of the option to select a magnum primer because either way you get a default value for start pressure which is at best a SWAG, and distance to the lands (which you cannot precisely account for in the software) is the one thing you CAN influence by how deeply you seat...the problem becoming you cannot effectively estimate the correct start pressure value any way you slice it. Either default value most certainly not correct in any case.

Now go away...you've proven that you're every bit as useful as a housefly.
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