Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Rifles, Reloading, Optics, Equipment
Reloading
I bet I'm not the only one using powder they've never used before
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="sfdoc2000" data-source="post: 2177323" data-attributes="member: 76742"><p>The other thing I have learned about Quickloads is that burn rate can vary with the load used. The Universal Gas Law, pV=nrT shows that with increasing pressure, the temperature of the gas increases linearly, which in turn makes the powder burn faster. I see this all the time where I often have to "tune" the burn rate coefficient to get the measured velocity to match the predicted velocity with all other factors being equal. This gets really critical when using powder loads near maximum where even small incremental increases in powder weight can drastically increase the maximum chamber pressure into unsafe zones. I try to use slow enough powders to get >98-99% powder burn without over pressurizing the chamber. Best to get 100% burn if you can. The SD's seem to be more consistent with a full burn. </p><p> Again, this is a simulation and the results are dependent on the parameters you enter into the computer program. Garbage in = garbage out. You still have to watch for signs of excess pressure in your fired cartridges whenever doing load development. Sometimes even a 50 FPS increase in measured velocity can result from a chamber pressure that is in the red zone. Seabeeken is right, using a .3gn step in your "guided ladder" in medium and large cartridges starting 1 grain below your predicted "best" load is good. If the lowest load gives your measured MV that is at or over where the program predicted the 'best' load would be, then DO NOT fire the high volume loads. Pull the bullets and use the lower load as the new midrange.</p></blockquote><p></p>
[QUOTE="sfdoc2000, post: 2177323, member: 76742"] The other thing I have learned about Quickloads is that burn rate can vary with the load used. The Universal Gas Law, pV=nrT shows that with increasing pressure, the temperature of the gas increases linearly, which in turn makes the powder burn faster. I see this all the time where I often have to "tune" the burn rate coefficient to get the measured velocity to match the predicted velocity with all other factors being equal. This gets really critical when using powder loads near maximum where even small incremental increases in powder weight can drastically increase the maximum chamber pressure into unsafe zones. I try to use slow enough powders to get >98-99% powder burn without over pressurizing the chamber. Best to get 100% burn if you can. The SD's seem to be more consistent with a full burn. Again, this is a simulation and the results are dependent on the parameters you enter into the computer program. Garbage in = garbage out. You still have to watch for signs of excess pressure in your fired cartridges whenever doing load development. Sometimes even a 50 FPS increase in measured velocity can result from a chamber pressure that is in the red zone. Seabeeken is right, using a .3gn step in your "guided ladder" in medium and large cartridges starting 1 grain below your predicted "best" load is good. If the lowest load gives your measured MV that is at or over where the program predicted the 'best' load would be, then DO NOT fire the high volume loads. Pull the bullets and use the lower load as the new midrange. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Reloading
I bet I'm not the only one using powder they've never used before
Top