Some where I read about this method of load developement. I can’t remeber if it was here or if anyone here uses it in thenload development. If not please point me to the correct forum. Otherwise I will proceed as if someone here knows what I’m talking about. I decided to try this method for the first time using my “new” Husqvarna custom model 640 chambered in 7x57mm. I still haven’t determined twist rate which I need to do. Nonetheless I started this test using Hornady 154grain SP’s, and IMR 4064. I shot three charge weights of three shots each. They were 36.1gr, 36.5gr and 36.9gr. Bellow is a picture of the groups. Obviously not the best groups but this is just the beginning. I have a feeling lighter bullets might do better. So now that I’ve shot these groups, and based on the results, what next?
Optimal Charge Weight load testing
- Thread starter KneverKnew
- Start date
Well, I would step the different charge weights by 0.3 gr for that case. Basically use 10% of the total charge weight as a step size.
What is the min and max charge weight for that cartridge?
You should probably determine twist on the barrel just so you know.
What is the min and max charge weight for that cartridge?
You should probably determine twist on the barrel just so you know.
Minimum is 32.9, max is 38.3. I still have room to go. Just my first try. Any suggestions would be great.
I also want to do the OCW test with my 6.5 Creedmore, K31 and Husqvarna M96. Miles to go before I sleep!
I’m trying @sstacllc ’s 10 round method on my new 6.5 barrel. I feel it holds the promise of less rounds on the barrel and time, in initial development. : http://www.65guys.com/10-round-load-development-ladder-test/
I did cheat a little and did a 10 round pressure test ladder first to establish my high range and get some idea where my target velocities would be.
I did cheat a little and did a 10 round pressure test ladder first to establish my high range and get some idea where my target velocities would be.
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Finding a sweet load for a rifle can be addictive or sometimes frustrating.
For your 7x57 you should probably check the twist on the barrel first to ensure the bullet should work. You can do that with a cleaning rod. Use a tight fitting patch and start the patch/rod into the bore. Put a mark on the rod so that you'll be able to see it after it's gone 12". Also put a mark on the rod to indicate a starting point. Now push the rod making sure it is turning as in following the rifling. As the first mark rotates one revolution mark this as the end. Measuring between the start and end is the twist.
What distance did you shoot the target at?
For your 7x57 you should probably check the twist on the barrel first to ensure the bullet should work. You can do that with a cleaning rod. Use a tight fitting patch and start the patch/rod into the bore. Put a mark on the rod so that you'll be able to see it after it's gone 12". Also put a mark on the rod to indicate a starting point. Now push the rod making sure it is turning as in following the rifling. As the first mark rotates one revolution mark this as the end. Measuring between the start and end is the twist.
What distance did you shoot the target at?
I appreciate the suggestions. Target range for now is 100 yards. Once a load is developed I can shoot a qualifier target at 100 yards, with the goal of putting three shots inside a two inch circle. This qualifies you to take that particular rifle to the 200,300 and 400 yard line. Not a hard task with scopes and a good load/ ammo. A little more of a challenge shooting open sights. My eyes aren’t what they used to be. LOL.
Still, I consistently get groups between 3/4” and 1-1/2” with irons on my Swedes and K31’s with M41 and GP11 surplus ammo. I just have a hard time keeping all three shots inside that dang little circle. So far I’ve Quayle’s one of my K31’s using a scope, my scoped 5.56 AR and my scoped 6.5C M5 build. This 7x57mm will be next.
Still, I consistently get groups between 3/4” and 1-1/2” with irons on my Swedes and K31’s with M41 and GP11 surplus ammo. I just have a hard time keeping all three shots inside that dang little circle. So far I’ve Quayle’s one of my K31’s using a scope, my scoped 5.56 AR and my scoped 6.5C M5 build. This 7x57mm will be next.
Here's a link to the website for the Optimal Charge Weight (OCW) system. There's a lot of reading here, but it's good stuff.
http://optimalchargeweight.embarqspace.com/
http://optimalchargeweight.embarqspace.com/
Thanks. I have read most of the information. Still processing it in my feeble brain. Got a good idea how it goes. Hence my initial efforts. I may do the ten round chrony method for a try.
Well then how about my other bullets...139 and 145??
I think the standard 7mauser load was around 140 wasn’t it? So if my twist is 1:9.5 or 1:10, what Bullet weights would be optimal?
I think the standard 7mauser load was around 140 wasn’t it? So if my twist is 1:9.5 or 1:10, what Bullet weights would be optimal?
So am I correct in thinking that with the ten shot velocity node test, shooting at a target isn’t really necessary? Sounds like you find thenvelocity mode first, then load up rounds to shoot for group. Sound right?
I would assume letting barrel cool between each of the ten shots.
I would assume letting barrel cool between each of the ten shots.
I'm not real familiar with the 7x57 but a little lighter bullet might be better. I suppose it depends on what distances you plan on shooting.
As far as I understand the 10 shot velocity test, yes you have it right. This method really relies on perfect loading techniques so that you can see the effect of increasing the powder charge while everything else is the same.
As far as I understand the 10 shot velocity test, yes you have it right. This method really relies on perfect loading techniques so that you can see the effect of increasing the powder charge while everything else is the same.
I stand corrected. A 154 grain Spitzer bullet was developed which gave a velocity of 2900fps (29” barrel).
Yes that is the premise. Scott’s videos go into more detail but if I understand correctly finding the center of a node with a velocity flat spot high or low of it and getting your Standard deviation low is going to be more benificial at long range than super tight groups at 100 yards. He also make the point that once found the same velocity node will work with any powder. These are my understandings, not speaking for Scott.
I do a 2 minute timer with my iphone between shots, during testing. I also try not to let a cartridge cook in the chamber. I use a small cooler with a hot water bottle to keep ammo around 80 degs F in winter. This way I am not over pressure in the summer.
Please advisor if the following test efforts sound correct.
I’m about to load up 10 rounds each of Hornady 139 gr BTSP’s and Speer 145 grain Spitser SP’s for a velocity node ladder test. I’m using IMR 4064.
My Husqvarna M640 7x57mm is built on a Husqvarna commercial 640 receiver. How does the strength of this receiver stack up against modern receivers such as the Winchester 70, which Hornady used for the book load developement? Max loads listed in the Hornady and Speer books are for stronger modern actions and say to work up loads cautiously in actions such as the model 98, which took to be a strong action.
My plan is to take the listed max load in the Hornady book for the 139’s and IMR4064, which is 41.5grains, and reduce by 1.5 grains, my start load for the test is 40 grains. Minimum start load in the book is 34.2 grains. So if I load ten rounds with .2 grain increments starting at 40 grains, my tenth round ends up being 41.8 grains, which is .3 grains over the book listed maximum load, should my M640 action with new 7x57mm barrel be able to handle it? Or course I’ll be checking pressure signs with each shot.
I’ll be testing V’s with my LabRadar. I will be shooting all ten rounds at one target at 100 yards just to see how they string out with the different V’s. I’ll be letting rifle rest 2 minutes between shots. I expect the barrel will still be getting slightly warmer with each shot despite the rest. So does my proposed testing method sound about right? Thanks for any help.
I’m about to load up 10 rounds each of Hornady 139 gr BTSP’s and Speer 145 grain Spitser SP’s for a velocity node ladder test. I’m using IMR 4064.
My Husqvarna M640 7x57mm is built on a Husqvarna commercial 640 receiver. How does the strength of this receiver stack up against modern receivers such as the Winchester 70, which Hornady used for the book load developement? Max loads listed in the Hornady and Speer books are for stronger modern actions and say to work up loads cautiously in actions such as the model 98, which took to be a strong action.
My plan is to take the listed max load in the Hornady book for the 139’s and IMR4064, which is 41.5grains, and reduce by 1.5 grains, my start load for the test is 40 grains. Minimum start load in the book is 34.2 grains. So if I load ten rounds with .2 grain increments starting at 40 grains, my tenth round ends up being 41.8 grains, which is .3 grains over the book listed maximum load, should my M640 action with new 7x57mm barrel be able to handle it? Or course I’ll be checking pressure signs with each shot.
I’ll be testing V’s with my LabRadar. I will be shooting all ten rounds at one target at 100 yards just to see how they string out with the different V’s. I’ll be letting rifle rest 2 minutes between shots. I expect the barrel will still be getting slightly warmer with each shot despite the rest. So does my proposed testing method sound about right? Thanks for any help.
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