What increments do y'all use when seating depth testing. I have heard folks doing as little as .003 and Barnes says .015. Would love to hear thoughts.
Seating Depth Increments?
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Rick Richard
Well-Known Member
I use the Berger recommended method. Fortunately most of the projectiles I shoot like either.010 or .030 OTL.
birddog 68
Well-Known Member
I have been working in .020 increments and fine tune once I find a preferred depth.
My last bullet I worked with preferred a .070 jump and I would have used a bunch of components finding that moving back only .003 at a time and probably would have moved to a different bullet thinking it wouldn't shoot.
My last bullet I worked with preferred a .070 jump and I would have used a bunch of components finding that moving back only .003 at a time and probably would have moved to a different bullet thinking it wouldn't shoot.
Rick Richard
Well-Known Member
From Berger regarding Elite Hunter and Hybrid Target bullets.
"A general rule of thumb with the Berger Elite Hunter and Hybrid Target bullets is to start your bullet seating depth testing at .015" off the lands. Then you work back into the cartridge case in .015" increments (.015",.030", .045", .060"). When you find a bullet seating depth that shows promise, you can test .005" to either side of that CBTO if you wish to see if accuracy can be improved. All bullet seating depth testing is done using the starting powder charge!"
"A general rule of thumb with the Berger Elite Hunter and Hybrid Target bullets is to start your bullet seating depth testing at .015" off the lands. Then you work back into the cartridge case in .015" increments (.015",.030", .045", .060"). When you find a bullet seating depth that shows promise, you can test .005" to either side of that CBTO if you wish to see if accuracy can be improved. All bullet seating depth testing is done using the starting powder charge!"
Laguna Freak
Well-Known Member
I've found that 0.050 to 0.070 thou off the lands is a good starting point with Accubond and Scirocco II in 4 bullet weights, 3 different rifles, and barrels from Steyr, Winchester, Brux, and Bartlein. Then fine tune when you ID a potential node. I like to find an accuracy node that is atleast 0.003" wide.
Perhaps an oversimplification but I always start out at .020 off and only tweak from there if I can't get .5 MOA or less. It seems that "closer" (but not too close) works for me the majority of the time. I don't know what the hierarchy is when it comes to manipulating controlled variables (which I understand, should be done one at a time) but I almost always get good results within .005 of .020. Of course, all bets are off when you are limited by mag length or when you have an ogive profile that does not give you a definitive "hard stop" at the lands. Just my .02.
Is that a long jump in your opinion? I guess that's what some rifles like. A node within .003 is tight by my standards, almost within my margin of error but I'm sure it can make a difference. What do you accept for run out? Just curious.
Laguna Freak
Well-Known Member
I used to think it was a long jump until all my rifles liked it. Now I think anything under 0.050" is tight to the lands. Actually all 3 of these rifles are loaded > 0.060" off the lands. I don't have any that like 0.050" but that's where I started load development after I figured out the first one years ago. Of course I only shoot 3 different bullet ogives in these rifles. One being ABLR. I don't load for anything else except a few handguns. I don't worry about run out. I guess I never had an issue at these seating depths. Maybe there is something to a neck full of bearing surface.
I've always been able to develop a load that suited me.I like to find a wider node but I don't accept anything less than 0.003".
I tried the the Berger method and found it lacking. Top bench rest and F-class shooters will tell you a seating depth node is only .006 wide. You may luck into a good node, but if you make big jumps you'll be skipping over good nodes. I shoot mostly heavy for caliber, high BC bullets in long range competition. They are very long and I want to make sure I maximize powder space while keeping my bullet away from the dreaded donut. I start .020 off the lands unless that won't fit in the magazine. I move back in .006 increments, even if I miss the first node window, the next depth will hit one. Once I find the window I move .003 above and below looking to find both ends of the window and shoot confirmation groups at the long end of the window. As the throat wears, it will stay in tune longer. I rarely have to shoot more than 4 or 5 depths before I find a good node. If I can't get there, I'll change powders or even switch to a different bullet. It works so well for my competition loads, I follow the same method with my deer and varmint loads.
nksmfamjp
Well-Known Member
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I hear what you hear…..0.006" wide nodes….maybe 0.012" on a big one….
If you are 0.015" off the node, what do you see?
Let's say you choose 0.030" increments…. Then you are 0.015" off at worst.
If you start 0.050" off of ideal and work towards ideal, do groups incrementally shrink until you get to perfect or are groups all over from big to small as you approach the node?
How many shots per group(same oal) as you approach the node? 1? 3? 5? 20? 50? 100?
If you are 0.015" off the node, what do you see?
Let's say you choose 0.030" increments…. Then you are 0.015" off at worst.
If you start 0.050" off of ideal and work towards ideal, do groups incrementally shrink until you get to perfect or are groups all over from big to small as you approach the node?
How many shots per group(same oal) as you approach the node? 1? 3? 5? 20? 50? 100?
MagnumManiac
Well-Known Member
After years of competitive LR shooting, my procedure always finds a measurement the bullet likes in the fewest number of shots.
I start touching, NOT JAMMED, then I go 3 shots for each measurement at .010" increments AWAY from the rifling.
Normally, between touching and .030" off I find the best depth, then I try +/- .005" of that, if .005" is still not quite there, very rare, I will try .003" +/- of the first measurement.
More often than not, say 9/10 times, my rifles all prefer somewhere between .010"-.020" off and then about .050"-.080" if I can't reach the lands with that bullet. This pattern repeats so often, it is normal testing procedure I use. There is one bullet that does not abide by this, and that is the Lapua Scener L in 6.5, it likes .005" jammed and will not shoot otherwise FOR ME & my 6.5x47…
A bullet that likes jump in my 264WM custom chamber is the 123g Nosler CC, it will shoot fantastic no closer than .050". It does not like this in my 6.5x47, it likes .015" off, go figure.
Cheers.
I start touching, NOT JAMMED, then I go 3 shots for each measurement at .010" increments AWAY from the rifling.
Normally, between touching and .030" off I find the best depth, then I try +/- .005" of that, if .005" is still not quite there, very rare, I will try .003" +/- of the first measurement.
More often than not, say 9/10 times, my rifles all prefer somewhere between .010"-.020" off and then about .050"-.080" if I can't reach the lands with that bullet. This pattern repeats so often, it is normal testing procedure I use. There is one bullet that does not abide by this, and that is the Lapua Scener L in 6.5, it likes .005" jammed and will not shoot otherwise FOR ME & my 6.5x47…
A bullet that likes jump in my 264WM custom chamber is the 123g Nosler CC, it will shoot fantastic no closer than .050". It does not like this in my 6.5x47, it likes .015" off, go figure.
Cheers.
MagnumManiac
Well-Known Member
@Pdyson,
Magazine length plays no part in this, none of my F-class or ELR rifles use the magazine, the rules state single loading on TOP of the follower, so why would you take magazine length into consideration?
I have LR repeaters too, but you throat your chamber to accomodate the cartridge to fit the mag, yes?
I agree with your seating depth method, but not all nodes are .006" wide, many are double that depending on throat design, proven fact.
Cheers.
Magazine length plays no part in this, none of my F-class or ELR rifles use the magazine, the rules state single loading on TOP of the follower, so why would you take magazine length into consideration?
I have LR repeaters too, but you throat your chamber to accomodate the cartridge to fit the mag, yes?
I agree with your seating depth method, but not all nodes are .006" wide, many are double that depending on throat design, proven fact.
Cheers.
Use .003 when you think you are close.
Use something wider to get you there, whether it's 10 or 15 or 5 or whatever.
It makes a difference. You can normally watch the groups open and close as you move either in the right direction or not, the trend should be apparent.
I try to settle on the longer side of a sweet spot, to allow for future erosion.
Use something wider to get you there, whether it's 10 or 15 or 5 or whatever.
It makes a difference. You can normally watch the groups open and close as you move either in the right direction or not, the trend should be apparent.
I try to settle on the longer side of a sweet spot, to allow for future erosion.
