Hoping to get some time to work up a few loads for my 7 mm stw today. Was going to work up five then make some adjustments then work up five and so on. What is the best way to test the loads. Squeaky clean barrel, shoot the first five, clean and so on? What do you guys suggest?
Best way to test loads?
- Thread starter Blacktail
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For developing a load, its the ladder test for me. Also known by the incrimental load development test, and others.
The short description would be shooting a series of rounds, each with different powder charges loaded in increasing incriments of charge wt in an attempt to find vibration nodes that minimize the dispersion caused by varying charge weights, while allowing an accurate, repeatable load to be found for a rifle, with a minimum round count being fired.
Ive got a document that does a passable job of explaining the ladder test. If you would like a copy, id be happy to email it to you.
Ive been working with a 7STW a lot lately. if youre interested in componet suggestions for an application...
The short description would be shooting a series of rounds, each with different powder charges loaded in increasing incriments of charge wt in an attempt to find vibration nodes that minimize the dispersion caused by varying charge weights, while allowing an accurate, repeatable load to be found for a rifle, with a minimum round count being fired.
Ive got a document that does a passable job of explaining the ladder test. If you would like a copy, id be happy to email it to you.
Ive been working with a 7STW a lot lately. if youre interested in componet suggestions for an application...
I agree that the "ladder test" is relatively efficient and accurate.
What I would consider as better method, due to less emphasis on any individual shot for decision making, is Dan Newberry's "OCW" method. Here is a link to Dan's site:
http://practicalrifler.6.forumer.com/index.php
I have used both methods extensively and while either beats the old methods by far, I find Dan's more reliable and easier to interpret.
/ubbthreads/images/graemlins/cool.gif
What I would consider as better method, due to less emphasis on any individual shot for decision making, is Dan Newberry's "OCW" method. Here is a link to Dan's site:
http://practicalrifler.6.forumer.com/index.php
I have used both methods extensively and while either beats the old methods by far, I find Dan's more reliable and easier to interpret.
/ubbthreads/images/graemlins/cool.gif
I don't think anyone has answered your question yet. The correct answer is probably "clean and cold," but I believe it depends on how you will use the rifle. For instance, if you will be doing long sessions of prairie dog shooting with the barrel dirty and hot, then that's how you should test. For target shooting at extreme ranges, you probably want the barrel clean. I am mostly a deer hunter, so it's the first shot that counts and that will be done with a cold barrel. Frequent cleaning at the range seems like a waste of time to me and I haven't seen any significant difference in accuracy at normal ranges, so I don't do it. A cold, dirty barrel is my standard. When I clean the barrel between shooting sessions, I always fire a fouling shot before I start any accuracy testing. I go hunting with a dirty barrel that I have run a dry patch through to remove the big crud, hoping to simulate the conditions under which it was tested at the range. Other shooters will have a different rationale and I would expect to hear from them here also.
justgoharder
Well-Known Member
blacktimber
Member
aginok,would you email me that document as well. Thank you!
jrdoty
Well-Known Member
Abinok can you email it to me also. Thank you.
300stw
Well-Known Member
how about a copy for me as wekk, thanks in advance
The way I do it is pick a perticular bullet and weight you want to shoot at X fps that is achievable of course.
Get a measurement of the ogive to back of case and start with 10k jump. This is a good starting point and in some rifles it's perfect and in some they may want more or less jump. It also will give pressure signs when tipping the jug to much.
I also like to do this part when it's hot and you are sweating like a whore waiting her turn in line for confession. Load 2 identical rounds and run thru the chrony. What you are looking for is velocity consistancy within 15fps or less and pressure signs. Continue loading and shooting 2 rounds till either you reach your velocity you want, or pressure makes you halt.
Once this is established and you have a load that has consistant 15fps or less, load 3 identical rounds and start your seating depth variations. 3 at 10k then 3 at 15k and so on in 5k increments and you will hit a node. Usually there is 2.
The ladder test in my opinion is that you are tuning the harmonics by powder charge with a certain oacl. Problem with this is that I do not want to settle for what the powder dictates. You might be able to get more velocity and the load be more efficient.
The way I was explaining above is I'm getting all I can out of the load with that bullet I can and I will tune the harmonics with bullet seating.
Just the way I do it and it's always worked for me.
Tim
Get a measurement of the ogive to back of case and start with 10k jump. This is a good starting point and in some rifles it's perfect and in some they may want more or less jump. It also will give pressure signs when tipping the jug to much.
I also like to do this part when it's hot and you are sweating like a whore waiting her turn in line for confession. Load 2 identical rounds and run thru the chrony. What you are looking for is velocity consistancy within 15fps or less and pressure signs. Continue loading and shooting 2 rounds till either you reach your velocity you want, or pressure makes you halt.
Once this is established and you have a load that has consistant 15fps or less, load 3 identical rounds and start your seating depth variations. 3 at 10k then 3 at 15k and so on in 5k increments and you will hit a node. Usually there is 2.
The ladder test in my opinion is that you are tuning the harmonics by powder charge with a certain oacl. Problem with this is that I do not want to settle for what the powder dictates. You might be able to get more velocity and the load be more efficient.
The way I was explaining above is I'm getting all I can out of the load with that bullet I can and I will tune the harmonics with bullet seating.
Just the way I do it and it's always worked for me.
Tim
