How many grains from node to node?

[searcher]

If that is what you are finding, then you have the wrong powder or other issues going on. When you are using the optimum powder for your case/bullet combination, and at a reasonably close seating depth, you should find a very repeatable load that shows up like a stable consistent girlfriend. When the combination is wrong...it will be like dating a girl with multiple personality disorder; you won't know who will show up at the door on any given date night. I've got the T shirt.

My definition of a "node" is a range of velocity in which the bullet maintains tight grouping. I'd venture to say this is universally accepted by more than a few shooters. That is not to say that a very minor tweaking of powder may be necessary to keep one in fine tune, but some loads are much harder to keep in tune at all as the good-grouping velocity range may have been very narrow to start with, if non-existent. I'm sure there are folks out there that have tried a handful of powders in their rig and never could find a solid, wide velocity range where their rifle shot fantastic. Sometimes, one gets lucky on the first powder. I have a .243 that found the standout powder after 12 powder changes - which is the most I ever had to try. It is now one of my most accurate rifles and accuracy wavers little during external ballistic changes. Had I settled on using all the published "accuracy loads" and most recommended powders for that caliber, I'd probably have cut up the rifle with my Sawzall.

 

[jxb]

3%, keep in mind we're working with percentages here, so 3% works while increasing... If I recall correctly checking my fps for each node also calculated out to ~3% between em.

example from stocks: your stock goes down 50%, it then must go up 100% to get back to break-even. Most people don't really understand that and why they get in trouble... but it is a good example to show how 3% down and 3% up is not the same number of grains of powder. Just another reason to start low and work up

 

[rardoin]

My definition of a "node" is a range of velocity in which the bullet maintains tight grouping. I'd venture to say this is universally accepted by more than a few shooters. That is not to say that a very minor tweaking of powder may be necessary to keep one in fine tune, but some loads are much harder to keep in tune at all as the good-grouping velocity range may have been very narrow to start with, if non-existent. I'm sure there are folks out there that have tried a handful of powders in their rig and never could find a solid, wide velocity range where their rifle shot fantastic. Sometimes, one gets lucky on the first powder. I have a .243 that found the standout powder after 12 powder changes - which is the most I ever had to try. It is now one of my most accurate rifles and accuracy wavers little during external ballistic changes. Had I settled on using all the published "accuracy loads" and most recommended powders for that caliber, I'd probably have cut up the rifle with my Sawzall.

OK

 

[ebb]

Sorry guys I have been occupied and haven't given this thread much attention. Storms are looming. My shutters are mostly up, and the rest of them will wait till I see if we are going to be affected. They are under the front and back porch and could go in the rain or dark, cause they are covered. An older neighbor is waiting to the last minute to decide, I think he wants to spare me the work if he can. I would like to do them now and avoid purring them up in the rain or dark if possible.

 

[Alex Wheeler]

I'm a 3% guy, and it's usually real close to that. Experience limited to using ladders at distance as Charlie mentions above.

I've seen the same thing from 21" sporters to 34" 1.450s, and barrels with tuners on and off. It seems we tune powder by pressure and not so much speed, is what that tells me.

Pretty simply find max - work down covering at least that much - if it sucks then change powders and start over.

Tom

This. Nothing seems to be able to change barrel frequency enough to make any difference.

 

[Idaho-Lefty]

After Buying, a 6.5 Creedmoor,. I NO Longer have, to "Worry" about,.. accuracy Nodes !
Yup,.. It's,.. THAT,. "Good" !
Once the 6.5 Cal., High BC, Bullet gets Afloat,. it STAYS afloat for,.. 4 Miles.
Some guy in Montana, Killed an Antelope at,. 1,507 Yards with,.. a 6.5 creed, using, a147 gr ELD-M !

 

[Idaho-Lefty]

Sorry guys I have been occupied and haven't given this thread much attention. Storms are looming. My shutters are mostly up, and the rest of them will wait till I see if we are going to be affected. They are under the front and back porch and could go in the rain or dark, cause they are covered. An older neighbor is waiting to the last minute to decide, I think he wants to spare me the work if he can. I would like to do them now and avoid purring them up in the rain or dark if possible.

Stay SAFE, ebb and,.. Good Luck !!

 

[Alex Wheeler]

I recently tried a ladder with IMR 4064 in my 6 BRA, it just seemed odd that the charges went straight up to the top and pressured at just over 3000 fps. It didn’t seem to pause at 3 % increments at all. Have you seen that before ?

Many times

 

[Doom]

I recently tried a ladder with IMR 4064 in my 6 BRA, it just seemed odd that the charges went straight up to the top and pressured at just over 3000 fps. It didn’t seem to pause at 3 % increments at all. Have you seen that before ?

Since you shot this at 500yds it appears that this rifle is very stable and is not exhibiting a specific node. If shot at 100yds I would expect all other the POI's would be the same or very close to the same. This is what Litz has eluded to in his PRS rifle.

Jeff Siewert made a comment about bore straightness on one of the Hornady podcasts having an effect on dispersion. I wonder if this one of the differences between custom barrels and production barrels that comes into play?

 

[nwmnbowhunter]

I recently tried a ladder with IMR 4064 in my 6 BRA, it just seemed odd that the charges went straight up to the top and pressured at just over 3000 fps. It didn’t seem to pause at 3 % increments at all. Have you seen that before ?

This looks great. It's going to shoot awesome.

 

[nmkid]

I believe that any NODE is only good for the day it was tested. My node testing showed constant changes.... I now save my testing components for practice on wind and lighting changes. If there are really nodes, why do we need scales that measure to tenths of a grain? But I am not a ballistic scientist....

Can you answer me this? I already have my 243AI load and sighted in for this winter's coyote season. Since sighting in I have been out to the range 3 times to verify and my groups never change. My rifle is very happy at .500 at 100 yards and it doesn't change regardless of which day of the week I go out.

 

[Alex Wheeler]

If I were too look at this again , it would be both sides of 31.7 and - 3% = 30.7

First, I would never look at a single shot ladder like that and make any decisions. Single shot ladders like that will fool you often. Sometimes what looks like a node is actually vertical, you just caught the right shots to many it look like a spot. If you were to go back and shoot groups, you would find the other node, it might not be a good node but it will be there. Also ladders that never stop climbing are usually a sign to switch powders or keep going up. Low pressure can look that way too. About all I use a true single shot ladder for is to find pressure and see if the powder is even worth trying to tune. We want narrow, climb, stop, climb, stop. Wide, round, no stop, and going down are all less than ideal in my opinion.

 

[Webster]

I am thinking about saving my bullets, powder, and primers, I don't need to get all the speed available out of any given cartridge. But I would like to get to a high point in the vibration cycle and get a good chance on an accurate load. In days gone by I would start a grain or grain and one half above min and go to max. I am tuning a 308 win load that Nosler gives for their 125 grain BT, with WIN 748 how many grains would I have to go to find the top of the barrel travel. I guess what i am asking is how many .01s does it take to get one complete cycle. Is this question even answerable?

Keep it simple. Go with the best group.