Top three things to reduce ES and SD

[DougMH]

So just how accurate are chronographs?

Sounds like lots of people put 100% faith in the data they spit out. How accurate would they measure one kernel of Varget velocity difference?

I didn't see the last part of your question. There's a good bit more that one kernel of Varget that can affect MV. In fact, the entire process from case, powder, primer and preparation come into play. I guess if you're saying theorhetically everything else is equal would it measure the difference of one kernel of Varget, I'd guess probably not. .1 grain, yes, but 1 kernel (approx .02 grains), probably not.

When you're able to get all else 100% equal, let me know and I'll back you financially to produce match ammo. It must be 100% uniformity.

 

[woods]

1. Seating depth
2. _____________
3. _____________

 

[DougMH]

3" Shoot-N-C target

300 Yds, Fairfax Rod & Gun Club, Manassas, VA

 

[Bart B]

The above groups and numbers are interesting, but I'm a firm believer that at least 15 shots per test is needed to get meaningful numbers. When the ES is not about 3 times the SD, I suspect the numbers are not too meaningful.

Doug's numbers are the best ones in my opinion.

As far as what 1 kernel of Varget (or any powder for that matter), us humans cause more velocity spread due to our inconsistancies of holding the rifle than that kernel's presence or absense will make. Clamp a barreled action with a .22 Hornet chamber and bore, shoot 20 rounds with it through a chronograph, then put the barreled action back in the stock and shoot it the same hand held against your shoulder. Several folks I've talked with about this say the clamped version gets 1/4 to 1/3 smaller numbers; sometimes as much as 1/2 and average muzzle velocity is higher.

 

[TXTrained]

shooting small groups at whatever range is the key...if you had a very small group...I'm talking about a 1000yds by the way not 300 or 400 and your ES or SD was high I would take the small group any day and run with it...if your load is what your barrel likes and is tuned it will compensate for your crony numbers..again go shoot that "good" load and see what it can do with your .3 grn changes in powder and go from there....good luck...go with what your small groups tells you!!!!

I agree with you.Chasing numbers is nit what you are trying to achieve .Placing bullets at at given distance in a tight group is it.
The numbers can tell you why you may have missed and it was not you.... with slow velocity at a long distance

 

[QuietTexan]

The point of the statistics is in their predictive value. When first round hits count (hunting or scored comps), doing everything to make that first round hit is all that matters. Group size does not matter (we use it to confirm the predictive statistics, but a group has no impact on the next shot taken), all that counts is the next single shot going where it needs to go. And since there's no empirical way to know until it's sent, the statistics are used to describe the odds that the bullet will go where it needs to go.

The majority of shooting statistics are pointless anyways because there's no standard population size for describing ES or SD, very few people talk about confidence levels, and essentially no one shoots enough data points for positive correlation. We can rule out certain combinations, but positively confirming the impact of adjustments is very difficult.

The good news is the same statistics that tells us our ES and SD is BS also tells us ammo only matters for about 10% of the overall picture anyways - half of shooting better is making better wind and range calls, and most of the rest is picking the right chambering for the job in the first place.

 

[TXTrained]

The point of the statistics is in their predictive value. When first round hits count (hunting or scored comps), doing everything to make that first round hit is all that matters. Group size does not matter (we use it to confirm the predictive statistics, but a group has no impact on the next shot taken), all that counts is the next single shot going where it needs to go. And since there's no empirical way to know until it's sent, the statistics are used to describe the odds that the bullet will go where it needs to go.

The majority of shooting statistics are pointless anyways because there's no standard population size for describing ES or SD, very few people talk about confidence levels, and essentially no one shoots enough data points for positive correlation. We can rule out certain combinations, but positively confirming the impact of adjustments is very difficult.

The good news is the same statistics that tells us our ES and SD is BS also tells us ammo only matters for about 10% of the overall picture anyways - half of shooting better is making better wind and range calls, and most of the rest is picking the right chambering for the job in the first place.

Quiet Texan, Well Said.

with at the ES & St. D numbers & Averages.. we can Never take the Human element and Mother nature out of the equation.
Rifle than have a great average but doe hit the mark on a Cold Bore Shot is Useless to me.
The only time the Extreme Spread & Standard Deviations really count is in Target Shooting with more than one shot .

 

[QuietTexan]

Every time I see ES and SD without the number of shots I pretty much ignore it - when people post the number of shots I care a lot more. Someone just yesterday posted a shot of a LabRadar with an ES of 1 and SF of 0.5.... for three shots. Don't get me wrong - was obviously three very carefully made rounds, and I think that's a cool achievement. But that data isn't necessarily useful for something like quantifying the change in velocity for a charge weight change, because there aren't enough data points to make the confidence intervals not overlap.

That’ll Work

Got some new Peterson Brass for the 28 nosler and was also wanting develop a load for some Berger 180 Hybrid Targets. 42 rounds in and I think we have a winner. The last photo was my final seating depth test between .08 & .09 from jam for comparison. .08 was probably going to hold a solid 1/2...

www.longrangehunting.com

 

[nealm66]

I noticed a difference with the new v3 auto trickler. Mainly the new fancy scale showing me my old rcbs balance beam and pact powder dispenser we're holding true at 1/10 of a grain which basically meant some charges were 1/10 off. Although, a 30 es only makes about a 2" difference @1000 yards if your shooting let's say a 6.5-300 with a 156 Berger @ 3150fps which still dings the 10" gong so I say , as long as I know my rifle is tracking good and I have a really good idea how fast my bullets going, go shoot! ( if you can find the bullets and primers)

 

[Axl]

I agree with you.Chasing numbers is nit what you are trying to achieve .Placing bullets at at given distance in a tight group is it.
The numbers can tell you why you may have missed and it was not you.... with slow velocity at a long distance

6BR4ME2 may be a little slow to respond- he posted that in 2006 and he hasn't been on here in almost a decade! lol

 

[TXTrained]

HA HA ..Oh well He missed out again..LOL Thanks

 

[Hondo64d]

What are the top 3 things you guys do when trying to reduce extreme spread and standard deviation? I've got a rifle that is shooting some pretty decent groups, but my ES and SD are quite high. Granted, I don't have the best chronograph, so maybe that's the problem... But for now, let's focus on reloading techniques.

Use uniform brass. I buy brass that I will be confident in its uniformity as it comes from the factory. I don't weigh brass or turn necks. So, I use Alpha or Lapua.

Weigh every charge as accurately as you can. I use a Lyman M5 scale and can literally see one kernel of powder move the pointer.

Pick a sizing method that gives you low runout, and uniform sizing. I use a honed Forster FL sizer Adjusted to bump my shoulders .002".

Annealing. I anneal prior to every resizing. I get a little more consistent shoulder bump by doing so.

Even though I do all this, I seldom use a chronograph anymore. Most folks preach small ES or SD but don't use enough data points (shots) to provide a high level of confidence in those numbers. As I understand it, it takes about 30 shots to give a statistically valid SD. I often see folks publish their SDs for three or five shots and it makes me chuckle to myself. The same goes for a pic of single three or five shot group on a target but that's another topic. In the end, all that really matters is what happens on the target. If I get consistently small vertical spreads at the ranges I shoot, I'm happy.

John

 

[TXTrained]

Use uniform brass. I buy brass that I will be confident in its uniformity as it comes from the factory. I don't weigh brass or turn necks. So, I use Alpha or Lapua.

Weigh every charge as accurately as you can. I use a Lyman M5 scale and can literally see one kernel of powder move the pointer.

Pick a sizing method that gives you low runout, and uniform sizing. I use a honed Forster FL sizer Adjusted to bump my shoulders .002".

Even though I do all this, I seldom use a chronograph anymore. Most folks preach small ES or SD but don't use enough data points (shots) to provide a high level of confidence in those numbers. As I understand it, it takes about 30 shots to give a statistically valid SD. I often see folks publish their SDs for three or five shots and it makes me chuckle to myself. The same goes for a pic of single three or five shot group on a target but that's another topic. In the end, all that really matters is what happens on the target. If I get consistently small vertical spreads at the ranges I shoot, I'm happy.

John

Well the last I shot I had Avg. 2996, High of3008, Low of 2983, SD of 10.8,ES of 25, out of 15 shots..All in same hole except one that was .25 out from my fault.
I do all the things you do.I point my bulkets,bullets, use a K&M Precision Arbor Press with Dial Indicator using a Wilson/ Sinclair Micro Adjust Bullet Seater. I have a Warner Sizing Die m are specifically for my rifle chamber.
Maybe some of this info will help. Best of Luck