ES/SD vs group size

[jxb]

Rather than start a new thread, I'll try resurrecting this one.

How much on average can a person expect bullet depth tuning to change group size? (in inches)

Say for example during a powder ladder test the small groups produce no single digit ES/SD, not even close however the groups with single digit ES/SD the group opens up about 3x (example 1/2" to 1.5")

I'm guessing I want those single digit ES/SD and tune seating depth to bring that group size back in, right?
If so, the question is how much improvement can I expect.

 

[Alex Wheeler]

Rather than start a new thread, I'll try resurrecting this one.

How much on average can a person expect bullet depth tuning to change group size? (in inches)

Say for example during a powder ladder test the small groups produce no single digit ES/SD, not even close however the groups with single digit ES/SD the group opens up about 3x (example 1/2" to 1.5")

I'm guessing I want those single digit ES/SD and tune seating depth to bring that group size back in, right?
If so, the question is how much improvement can I expect.

Well, you already found small groups though. Thats what we are trying to do right? But, I do understand what your saying. In my experience adjusting seating depth can change es/sd as well. So its not like you can just take a low es load, adjust seating until it shoots and expect the es to be what it was before you did that. Aside from that, bringing in a bad powder change with seating depth or any other means like a tuner is just not going to work out well in my experience.

 

[mikecr]

I see 3 separate things having big affects to results:
1. Tuning prerequisites; shooting system quality, primers/striking, and optimum seating
2. Powder tune
3. Barrel tune

While prereqs remain an abstract, forget tuning. You ain't ready.
Barrel tune, given compensation, is very powerful to accuracy.
Without powder tune, you can slip in & out of barrel tune, yet a perfect powder tune can leave you away from barrel tune.

Of these, I believe seating is most dominant, followed by barrel tune.
As far as powder, I want highest MV AND low muzzle pressure, with a given bullet and barrel length, at SAAMI max pressure, with 100-104% load density, -to begin.
Then I back off from that and work up into barrel tune.
IF ES/SD are too high there, time to try another powder meeting described requirements.
But I'll never give up barrel tune for low ES/SD.

 

[jxb]

Thanks Alex and Mike, yeah I should have qualified that as I was shooting at 100yrds and the thought was I wanted not only a good group but also low SD/ES to hold group consistency at long distances.

Maybe I'm just over thinking it, but really what I was asking is simply how much can a person expect bullet seating depth to change group size. I was also apparently thinking too simplistic in that my ES/SD wouldn't change a lot with bullet depth, but maybe it could change enough to be right back where I was with good groups (1/2 MOA @ 100yrds or less).

6GT, 103 VTAC, Varget. I have both Alpha and Hornady brass, going to stick with Alpha now that I got more as it appears more consistent. I don't shoot competition, just want to get it dialed in so it will shoot reasonably well near and far.

 

[Bill Norris]

Thanks Alex and Mike, yeah I should have qualified that as I was shooting at 100yrds and the thought was I wanted not only a good group but also low SD/ES to hold group consistency at long distances.

Maybe I'm just over thinking it, but really what I was asking is simply how much can a person expect bullet seating depth to change group size. I was also apparently thinking too simplistic in that my ES/SD wouldn't change a lot with bullet depth, but maybe it could change enough to be right back where I was with good groups (1/2 MOA @ 100yrds or less).

6GT, 103 VTAC, Varget. I have both Alpha and Hornady brass, going to stick with Alpha now that I got more as it appears more consistent. I don't shoot competition, just want to get it dialed in so it will shoot reasonably well near and far.

There is no set amount per say that any adjustment will change group size. Each rifle/load combination will demonstrate different changes in group size.

 

[jxb]

Well, you already found small groups though. Thats what we are trying to do right? But, I do understand what your saying. In my experience adjusting seating depth can change es/sd as well. So its not like you can just take a low es load, adjust seating until it shoots and expect the es to be what it was before you did that. Aside from that, bringing in a bad powder change with seating depth or any other means like a tuner is just not going to work out well in my experience.

I didn't really expect the ES/SD not to change, but I have no experience to know how much they might change. Currently my good groups have about 3x higher ES/SD and my single digit ES/SD have about 3x larger groups. I do want the consistency at 300-1000 so I was thinking I need to keep those ES/SD low as possible and of course have a good group size too.

So now I'm wondering if I tune seating depth how much my ES/SD might change, I was hoping not a lot but maybe I simply need to see.

I have other rifles I mostly never shoot past 450yrds so it's pretty much find the load they like for a given bullet and move on. However my 6GT, 6.5 Creed, and 7Rem Mag I'd love to try out to reasonably far distances, certainly 600-1000 so as I tune loads for them this question came up.

as far as loading I weigh each load +/- 0.02gr and use expanding mandrel for seating consistency. Anneal between loads. I don't sort bullets, but I do brass by manu and of course by firings and keep everything logged and labelled. I don't turn necks, but I do bump shoulder. All this meaning I'm not expecting the kind of consistency competition folks attain, but I am looking for the low hanging fruit.

 

[jxb]

Really the only reason I went down this road was I've read over and over that small groups at 100 many times don't carry through at distance and keeping the ES/SD low is one of the keys to doing that. If that's bogus, then I'll simply tune powder charge at say 300 and give the longer stuff a try.

Of course more recently I see some folks say they've moved to tuning seating depth, then move to powder. So yeah it's a little confusing trying to figure out the correct methodology.

I've been loading for decades, but before it was more for hunting and sub moa groups were the target and nothing over 450yrds. Now I'm targetting sub 1/2moa plus I want to stretch it out well over 500yrds. So I need to step it up a bit and why I'm asking.

 

[Fuj]

but I am looking for the low hanging fruit.

Cases annealed ?? Using any type of internal neck lube ??
Any carbon in the necks ??......Mechanics of bullet release
can be considered your low hanging fruit.

 

[RegionRat]

If you plan to shoot Mid Range Matches at 600 or more, then you can get some useful work done at shorter distance but my advice is to stop kidding yourself and get to 600 as soon as possible.

The only thing you buy yourself at 100, then 300... is a little less wind penalty. However, for that benefit you will also miss out on learning how the vertical behaves.

You could throw poor ammo at 300 and when you take it to 600, you will find you were wrong.

The flat part of the trajectory can mask performance issues that only show up down the road where the arc spreads due to poor tune and poor velocity stats. Wind calls aside, there is no substitute for the experience of learning to utilize short range testing, by first suffering at distance.... YMMV

Good Luck and in for the range reports.

 

[jxb]

Thanks I have no plans to compete, sounds too much like work and I have a job. This is more figure it out before I retire and can play more ;-)

I appreciate everyone's input.

 

[tom]

I posted this on Alex's thread but here's a look at something we see often when tuning at distance.



There's no real patterns, as tomorrow the good zone will 99.9% of the time still be between 31.01 and 31.15, but the ES may or may not flip flop. Basically if you are reasonable (like 25ish or less), just worry about the groups at the intended distance for comp guns, or maximum intended for hunting guns is my best advice.

Tom

 

[williepete]

Check out this video
I think you will find what you need

 

[jxb]

Check out this video
I think you will find what you need

Oh yeah the Yellow and Blue boxes loving guy... lol
I enjoy most of his content but I hadn't seen this one. I like how he breaks it down so a not so bright country boy like me can get it. I'm not a competition shooter so I don't get some of the lingo folks toss around but this was easy as pie to get.

I like the KISS part too.

 

[ebb]

7 year old post and the OP has not been seen since 2017

 

[Ccrider]

Rather than start a new thread, I'll try resurrecting this one.

How much on average can a person expect bullet depth tuning to change group size? (in inches)

Say for example during a powder ladder test the small groups produce no single digit ES/SD, not even close however the groups with single digit ES/SD the group opens up about 3x (example 1/2" to 1.5")

I'm guessing I want those single digit ES/SD and tune seating depth to bring that group size back in, right?
If so, the question is how much improvement can I expect.

Adjusting seating depth can change group size significantly, just like adjusting powder charge or neck tension.

I posted this on Alex's thread but here's a look at something we see often when tuning at distance.

View attachment 1518511

There's no real patterns, as tomorrow the good zone will 99.9% of the time still be between 31.01 and 31.15, but the ES may or may not flip flop. Basically if you are reasonable (like 25ish or less), just worry about the groups at the intended distance for comp guns, or maximum intended for hunting guns is my best advice.

Tom

Tom said a lots. Trust the target at the distance you plan to shoot.

It is easy to get hung up on low single digit es. Seems like more often than not, I am finding tune not to be at my lowest es, both for 100 and 600.

I think you should learn to tune at 100 and then move to distance. There is too much noise at 600 to have a good shot at figuring it out if you don’t have the basics down.

 

[Rsadams]

Work up a load that works in your rifle and let the paper do the talking... Use the crono to get you an idea of speed...

 

[Bill Norris]

Adjusting seating depth can change group size significantly, just like adjusting powder charge or neck tension.


Tom said a lots. Trust the target at the distance you plan to shoot.

It is easy to get hung up on low single digit es. Seems like more often than not, I am finding tune not to be at my lowest es, both for 100 and 600.

I think you should learn to tune at 100 and then move to distance. There is too much noise at 600 to have a good shot at figuring it out if you don’t have the basics down.

Work up a load that works in your rifle and let the paper do the talking... Use the crono to get you an idea of speed...

Some of the best advice you will find right there in those two post. Numbers mean absolutely nothing if the paper is showing bad groups. Since I experienced a 5-shot one hole 1/4 inch group and seen over 100 fps variation on the chrono for that group some years back I decided not to depend on the chrono for load development. Checking the speed after the load is developed is the main job of the chrono for me.

 

[ebb]

When they have competitive rifle shoots where winners are given awards, such as national champion, or world champion or event local events and smaller shoots. I have never heard of anyone getting fake wood for the lowest ES numbers. Its always the smallest group or the closest to the little tiny dot in the middle. Even braggers like me carry a wallet group not a copy of my ES or ED numbers.

 

[jxb]

7 year old post and the OP has not been seen since 2017

yeah well the content doesn't age like us. It fit best as I could see for my ask so I resurrected it.

 

[jxb]

Well seems we're way off task of my original ask, but that's ok it's all good info and I thank everyone for their input.

I'm not hung up on single digits at all, I was simply relaying what I saw. I have seen people say you need low SD/ES to help contain dispersion at distance. I wasn't trying to imply I thought "low" meant single digits, but in my powder testing I had a huge gap between low and next up. So I thought well if I can use the low SD/ES load and tune the group with seating depth then maybe I'll end up with the best of both and good groups at 100 and acceptable at distance. Most of my rifles I shoot to 450yrds, I simply find a powder load that shoots small groups and use that (coal is factory due to mags and such), like forever. The sage rats don't care... Then I got the idea it would be really cool to shoot at distance and a couple rifles fit for that. So here I am asking a few questions on stuff I've not really messed with.

My ask was "How much on average can a person expect bullet depth tuning to change group size? (in inches)"

I asked because I wanted to know for any given rifle what kind of movement I could expect. I know with powder it's in inches but I didn't really know for seating. Bill actually answered that with basically it's different with any given situation. Which told me what I needed to know. Do it and see. ;-)