• Watch Out for Scammers!

    We've now added a color code for all accounts. Orange accounts are new members, Blue are full members, and Green are Supporters. If you get a message about a sale from an orange account, make sure you pay attention before sending any money!

Tightening up ES and SD numbers?

F

fw707

Full Member
Full Member
Minuteman
Nov 12, 2010
1,376
2
68
KY
Well, I shot some rounds through a new chronograph at the range today, and let's just say the results were, uhhhhhhh, enlightening and informative.
If the SD and ES numbers aren't where they need to be, where do you start trying to make them better?
I've got some different primers on the way as a first step, but what's the best route to take from there?

Thanks!
 
Re: Tightening up ES and SD numbers?

In my opinion, primers are a minor factor. Usually, if nothing else, they are consistent, regardless of brand.

You need to get into the drudgery of case preparation and evaluation, which is a very deep subject. You need to take a hard look at the bullet you are using and consider alternatives.

That's just for starters. There are many factors that contribute to the numbers you see on the chronograph, even the propellent, some burn more consistently than others, velocity will be erratic, in some cases, the contributing factors are extensive, but it's doubtful that you will solve the puzzle just by switching primers. BB
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">but it's doubtful that you will solve the puzzle just by switching primers. BB </div></div>

Thanks BB.
If you'll go back and read my post, you'll see that I mentioned the primers as a first step.
 
Re: Tightening up ES and SD numbers?

Poweder charge and case prep first, bullet next. I do not trust my rcbs chargemaster. it is only accurate to about .15 grains in my experience. So verify all your LR loading if using one. Next is to primer pocket uniform, neck reaming, and using bushing dies. Primers are generally fine as long as you using match primers.

What were your ES and SD numbers?

as far as the bullet goes, use good "match" quality bullets and measure using a comparitor. AMAX, Noslers have been good to great in my experience. SMK's are ok to almost good in terms of consistency. I have one 175 smk that is so far out of spec that it likely cause an over pressure incident.

Your charge weights are likely suspect.
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jeepocabra</div><div class="ubbcode-body">

Your charge weights are likely suspect. </div></div>

I have been using a Chargemaster, but I'm going back to the Redding dump measure and the trickler that I used before I got the Chargemaster to see if it helps.
The best load I had was an ES of 35 and an SD of 13. Two others I tried weren't even close to that.
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
Thanks BB.
If you'll go back and read my post, you'll see that I mentioned the primers as a first step.</div></div>

Yes, I actually read your post very carefully and my comprehension is still, (keep fingers crossed) better than average. Now, if you read my post again, the little nugget of information I was gently trying to convey is; your primers are, (any brand) virtually the most consistent component in your load, so while there is a difference in intensity, from one brand to another, that intensity is remarkably consistent, brand A or brand B.
Maybe you should look elsewhere. Keep the same primer as a baseline. Don't change it until justified. Just my opinion, for what it's worth. BB
 
Re: Tightening up ES and SD numbers?

Chargmaster is plenty accurate for consistent loads (assuming you don't have your cell phone sitting on top of it or something silly, and just pay attention to make sure it doesn't overthrow).

Use good brass (Lapua) or do good brass prep and use good primers (I prefer BR2). Then do OCW/Ladder test with aid from the chronograph. Find a nice "node", refine till you find good ES/SD -- THEN tweak seating depth to make it group (may then need to go back and tweak the charge again to get back in the consistency 'sweet spot').

Without a chronograph (or lots of *extended* range testing during load development), stumbling onto a load that groups well (at 100 yards anyway) AND has consistent velocity is pretty much a crapshoot.
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jeepocabra</div><div class="ubbcode-body">as far as the bullet goes, use good "match" quality bullets and measure using a comparitor. AMAX, Noslers have been good to great in my experience. SMK's are ok to almost good in terms of consistency. I have one 175 smk that is so far out of spec that it likely cause an over pressure incident.</div></div>
I just tried some 175 smk's for the first time and im very pleased with the consistent results. the weights weren't all over the place, and the meplat's were all pretty uniform. I'm mucher more happy than when I used to shoot the 168 smk's, as those were plenty inconsistent
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
Thanks BB.
If you'll go back and read my post, you'll see that I mentioned the primers as a first step.</div></div>

Yes, I actually read your post very carefully and my comprehension is still, (keep fingers crossed) better than average. Now, if you read my post again, the little nugget of information I was gently trying to convey is; your primers are, (any brand) virtually the most consistent component in your load, so while there is a difference in intensity, from one brand to another, that intensity is remarkably consistent, brand A or brand B.
Maybe you should look elsewhere. Keep the same primer as a baseline. Don't change it until justified. Just my opinion, for what it's worth. BB
</div></div>

BB, apparently I have offended you, and I didn't intend to do that. I was just saying that I'm switching primers first because that seems like the simplest thing to do <span style="text-decoration: underline">first</span>.
I'm shooting CCI 200 primers, and folks on here seem to get good results from BR2's.

I appreciate your reply, and I'd appreciate anything else you could add.

Thanks!
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mattj</div><div class="ubbcode-body">Chargmaster is plenty accurate for consistent loads (assuming you don't have your cell phone sitting on top of it or something silly, and just pay attention to make sure it doesn't overthrow).

Use good brass (Lapua) or do good brass prep and use good primers (I prefer BR2). <span style="color: #FF0000">Then do OCW/Ladder test with aid from the chronograph.</span> Find a nice "node", refine till you find good ES/SD -- THEN tweak seating depth to make it group (may then need to go back and tweak the charge again to get back in the consistency 'sweet spot').

<span style="color: #FF0000">Without a chronograph (or lots of *extended* range testing during load development), stumbling onto a load that groups well (at 100 yards anyway) AND has consistent velocity is pretty much a crapshoot.</span> </div></div>

Thanks Matt!
I had been working up accurate loads at 100 yards, and hoping a tight group was an indication of consistency. Then I was getting a MV from LR trajectory to enter into my ballistics program. Some loads did better than others, and after shooting through the chrono yesterday I see why they did.

I'm shooting Lapua brass, H4350 powder, VLD's, and Scenars, bumping the shoulder back .0015 in a Forster FL die,and measuring my seating depths to the ogive with a comparator. I'd have to check my notes to be sure, but I think I'm running around .003 neck tension.

Looks like I just need to go back to basic load development while shooting all of the loads through the chrono as I go this time.

 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: fw707</div><div class="ubbcode-body">I've got some different primers on the way as a first step, but what's the best route to take from there? </div></div>

New primers == new recipie!

Getting ES and SD down requires paying attention, not just at the reloading desk, but also at the range. At the reloading desk, you need to make sure that all primer pockets are cut to the same depth, that all flash holes are of the same diameter, that all cases have essentially identical measurements. Then the fun begins.

First use nothing less than match grade bullets {SMK, scenar, Berger,...} You can do additional sorting by weight, shank length, ogive length...

Sort your cases by headstamp, and if possible use cases from the same lot (lot = production run from the same shift.} You can do additional sorting by weight,...

Run a test on your charge weight measurement device. I use a toothpick on my scale. I first bounce the CW downward very gently, and see if it returns to the same number, then I prick the platen upwards and see if if come to the same number. If it does not, then I take the scale apart clean up the bearings, flucrum, use a very light coating of gun oil, and retest. You can't trust a scale that does not measure the same CW the same every time.

Once you get a scale measuring accurately, then you start OCW testing. OCW is about finding the CW at which your gun shoots well (note: not best), and then finding the window of CW where the whole window shoots well. This window, then, tells you how sensitive to CW this particular loading is. If you find an OCW node near the expected MV, it is likely that your CW window will be at least 0.4 gr wide--almost wide enough to throw and go (and sometime it is!)

Once the CW is sorted out, you then run seating depth experiments to desnitize the cartrige to the chamber and lands in the gun. Once this is sorted out, your ES and SD will likely hav come down into the desirable range any SD less than 15 fps is pretty good, and getting better than this requires lots more dilligence and patience.
 
Re: Tightening up ES and SD numbers?

I am using CCI 200 primers in my 308 load and getting great results. Believe it or not the BR2s did not group as well.

I agree with Buzz, brass prep is probably the biggest issue with consistancy. I use a Redding full length bushing die without the bushing to bump the shoulder back just enough to get the proper head space. Then I use a Lee collet die to neck size. After that I trim to 2.009" +-.001". I am annealing the necks every firing.
 
Re: Tightening up ES and SD numbers?

What I'm wondering. First what rifle? Second, were you satisfied with your groups <span style="text-decoration: underline">before</span> you saw your readout numbers on the chronograph? Third, what ES etc. where you anticipating? I hope you weren't expecting unrealistic numbers? "ES of 35 and an SD of 13" in a match quality barrel should produce fairly decent groups? (edit: if you do your part, lol) And, does your chronograph have a proof channel? BB
 
Re: Tightening up ES and SD numbers?

OP,

When I start load development on a new rifle I pick my starting point based on other rifles, loading manuals and past experience. While I'm a Lapua slut by nature it's not the be all end all of rifle brass I once thought it was. I've found that in two of my three 260's it's actually slower in velocity and less accurate than the RP or WW offerings. Uniform neck tension or lack there of and run out of a loaded round is probably the biggest culprits to accuracy degradation.

Primers do make a difference despite what other may say. I've switched to the CCI BR2 in my 260's and shot well over 5k CCI450's in three 6BR's and one Dasher. The CCIBR2 simply rocks in all the rifles I've tried them in except for one.

Powder, my favorites are H4350, H4895, Varget and RL-25. I use these in all my rifles and all have served me well.

Bullets, 139 Lapua Scenar, 105 Berger VLD, 105 Berger Hybrid, 180 Berger VLD, 175 SMK & 107 SMK is what I've shot the most of. The VLD's are fairly finicky as to seating depth but do shoot once the sweat spot has been found. The Scenars & SMK's tune easy and are much less finicky.

Not knowing what caliber you're working with makes it hard to make recommendations but, there are several things that I've found that cross from rifle to rifle.

I could right volumes on case prep and rifle tuning coming from a strong BR back ground but I wont. I'll just hit the high spots and what I do for my field rifles.

First, uniform neck tension and proper FL sizing. Get that right and consistent first and foremost. .002" neck tension is what I've found to work best with .003" being my absolute max. Just for conversation, I neck turn. Chamfer the case mouths with a VLD tool, Sinclair has a good one. Use the Redding type "S" FL dies with a bushing .002" to .003" smaller in diameter than your loaded necks. Redding Imperial sizing die wax has no equal. Bump the shoulder no more than .0015“ to .002” max. Use the black expander ball to hold the decapping pin in place, it wont drag the ID of your case necks. The silver expander ball will drag the ID of your case necks and this will induce run out.

Rifle brass, new rifle gets new brass. All the same head stamp. Try them all to find what works best in your rifle if you can as this is one area that can make or brake you. Don’t dismiss RP or WW brass as it seems to be fairly good these days.

Prime your cases by feel. What I mean is when you feel the primer bottom out, stop applying pressure.

Powder charge, weigh them all. Throwing is fine but, weigh them prior to dumping. I use a Harrell’s Premium Culver type and weigh my charges after throwing. Every time I don’t weigh my charges it bights me in the ass. Weigh your charges. For a starting charge weight I start at "X" and go up .5 at a time until the rifle shoots or shows pressure. If the rifle shows pressure before it shoots I change the primer or powder, usually the powder first and start over. Some rifles like the BR or Dasher will shoot differently with as little as .2 of powder charge weight difference while others like the 260 can show a difference with as little as .3 grains.

Bullet seating depth, VLD's touching to +.015" in is what usually works best but, they are finicky and will get out of tune. You have to stay on top of them to keep the rifle in tune and shooting to it's max potential.

Scenars/SMK's, jumping .005" is where I'm at but .010" has worked OK in some rifles. The Hybrids seem to work jumping as much as .050" in some rifles.

VLD bullets in BR rifles = Good
VLD bullets in field rifles = bit ass

Test in ideal conditions, early morning or late evening. Three shot groups at first to weed out what doesn’t work. If shots 1 & 2 are 2” apart, shot # 3 isn’t going to tighten the group up. Initial testing at 100 yards, proofing at 300 yards. Your looking for round or triangular shaped groups, not stringing or two in a hole and one out type stuff. Make your shots count and watch everything like wind, shooter habits, rear bag, thumb pressure, cheek weld and eye relief just to mention a few.

It’s all about consistency behind the rifle and at the loading bench. Quality built rifles are very capable of groups in the .1’s with relative ease. .2’s are almost the norm and what you should expect if all of the above is adhered to.
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">"ES of 35 and an SD of 13" in a match quality barrel should produce fairly decent groups? (edit: if you do your part, lol)</div></div>

A load with inconsistent velocities can group great at 100 yards -- but becomes a factor at longer ranges.

Zediker's book recommended < 11 SD -- I like to see it in the single digits (which in my experience is obtainable with good components without resorting to sorting and such).
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">What I'm wondering. First what rifle? </div></div>

Actually, 3 rifles.
A .260 with an 8.5 twist Bartlein.
A .260 with an 8 twist Krieger.
A 6.5x47L with an 8.5 twist Krieger.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body"> Second, were you satisfied with your groups <span style="text-decoration: underline">before</span> you saw your readout numbers on the chronograph? </div></div>

Yes, my 100 yard groups were fine, but I had occasional unexplained fliers at LR. I know I'll always have those, but they seemed a little too frequent.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body"> Third, what ES etc. where you anticipating? I hope you weren't expecting unrealistic numbers? "ES of 35 and an SD of 13" in a match quality barrel should produce fairly decent groups? (edit: if you do your part, lol) </div></div>

I expected about what I got. I'm not naive enough to believe that I had stumbled upon consistent loads without using a chronograph working up my loads.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">W And, does your chronograph have a proof channel? BB</div></div>

Nope. You're over my head now.
It's a CED Pro Chrono Digital.
 
Re: Tightening up ES and SD numbers?

Mr. Roscoe,
I really appreciate you taking the time to type up a post with that much information!
I'm using a lot of the techniques you mentioned, and you can bet I'll get a lot of the other stuff lined out before my next trip to the range.

Thank you!
 
Re: Tightening up ES and SD numbers?

Good, concise post by wnroscoe. Follow his advice, if you can.

However: don't misquote me here; or put words in my mouth.
"Primers do make a difference despite what other may say" That's not what I said, at all. Of course primers can make a difference, I said they are consistent, within a brand and lot# and probably would not account for his spread in numbers. And, they would not be <span style="text-decoration: underline">the first thing</span> I would change, as a remedy. That's an opinion, based on my experience and it's possible Mr wnroscoe and I disagree. BB
 
Re: Tightening up ES and SD numbers?

The biggest contribution to lower ES/SD numbers for my loads was to spend some extra time on the cases. After the usual ladder test and fine tuning of load for accuracy on the target, I found that better "numbers" came from weight matched cases, neck turning new brass after fire forming, annealing after every firing, and using a Sinclair Expander die as a last step before loading. When seating bullets I look for a consistent "feel" on the press handle and set aside any case that needs more or less effort than the rest.

As for Primers? I use eithe BR-2's or Wolf. Hard to see any improvement in the performance of the twice as expensive CCI's.

ES/SD for my loads I go to the above trouble to assemble are in the single digits. Best ever was an ES of 5 fps for 10 rounds. The average is usually at 8-9 fps.
 
Re: Tightening up ES and SD numbers?

Thanks for the info!
I'd like to try some of the Wolf primers but nobody close has them and I don't want to pay the Haz-Mat just to try them out.

I shot another rifle through the chrono yesterday, but it was too late for me to deal with a bunch of numbers last night.
These are the numbers from the last 11 rounds I had in a box:

First string:

2886 (clean barrel)
2867
2861
2861
2861

AVG. 2867
ES: 25
SD: 10

Second string:

2873
2867
2873
2879
2879
2867

AVG. 2873
ES: 12
SD: 5


Now I'm wondering how I can apparently do enough things right on one load to get those results, and still get such bad results on the others.
 
Re: Tightening up ES and SD numbers?

I think you start with a good case and primer, properly prepped. I, too, swear by the CCI BR-2 (and BR-4). Once that's done, treat this combination as a constant, not a variable.

A load is built based on the bullet and that original constant. Change the bullet and you're starting a completely new load all over.

Powder charge and seating depth become the final veriables, work them one at a time, powder charge first.

While chrono numbers, ES and SD, are important to some, they mean diddly squat to me. I think Chronos are simply incapable of producing numbers that are reliable in such small increments; and that when ES and SD are 'good', I seriously doubt they have a meaningful relationship with what's actually happening on the target.

While I like the CCI BR brand, I use the CCI standard primers in the same configuration (i.e CCI 400 for CCI BR-4's) for load development.

My reasoning for this and other points may appear obscure, but it has worked for me.

I build 'matched loads', which are different in concept from the commonly described 'match load'. A match load is what one uses for matches. A matched load is all about the barrel. The goals are very similar, but the concept is different (to me anyway.).

The matched load seeks to explore the accuracy node, to find point in the muzzle's harmonic cycle where the barrel is least sensitive to load variances. A good 'matched load' is what I term <span style="font-style: italic">robust</span>, or independent of critical features, where small variances negate its effectiveness.

By such a definition, a load that is accurate with a standard primer can only get more accurate with a match primer. By such a definition, jump distance variation due to manufacturing ogive variations are not a critical factor that invalidates the load's effectiveness. That sort of thing.

In all of this, my guage is the target and only the target. I have followed ES and SD in the past, and all I've been able to conclude is that the target and ES/SD are seldom having the same conversation. I doubt they even speak the same language.

I have honestly tried to prove otherwise, but I simply haven't been able to do so in a manner that is convincing for myself, let aone others. If it works for you, great; it doesn't for me. IMHO, the Emperor's new Clothes and ES/SD are cut from similar cloth. My Chrony went titsup several years back, I still haven't replaced it.

Greg
 
Re: Tightening up ES and SD numbers?

I think bench method might have just a bit to do with ES.

I've noticed it's way easier to get lower ES numbers, the heavier the barrel is. On a standard AR-15 20" barrel, if you get your numbers below 40, that is decent.

The heavier the barrel is for a .223, the lower the ES numbers tend to go. I think this is a result of recoil (or recoil control) more than anything.

The easiest to get low numbers for me is the .308 with 190+gr bullets.
 
Re: Tightening up ES and SD numbers?

+1 on Greg's post.

Do your development at the longest range possible and find the load with the least vertical.

By definition, that load has the lowest ES and SD
 
Re: Tightening up ES and SD numbers?

A note on your chronograph: much like a digital scale, the output from your chronograph is only as accurate and precise as the instrument is capable. You should try and be as consistent as possible when using the chrono to limit its internal error - full shade, or full sun, full sun with cardboard over the sensors...

The pro chrono I had, and suspected was giving incorrect or inconsistent numbers in the late afternoon, proved to be off and inconsistent when we tested it inline and side-by-side with another chrono. I built a cardboard enclosure for it (all sides except the bottom) and that helped lessen the inconsistency.

This is just intended as food for thought as you try and tighten up the magical ES/SD numbers.
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">However: don't misquote me here; or put words in my mouth.
"Primers do make a difference despite what other may say" <span style="font-weight: bold"><span style="color: #FF0000"><span style="text-decoration: underline">That's not what I said, at all.</span></span></span> </div></div>

BB, never said you did and my post wasnt aimed at you or anyone else. Fact is, there are those that will say primers dont make a difference, a seating depth change of only .005" is a waste of time or neck tension of .002" or .005" is the same/same.

Things I say concerning reloading, shooting or building rifles are based on what I know to be fact and what I've experienced personally.

For those that dont know try this as an experiment. Take your favorite load combo and just change the primer, load as many differnt 3 shot loads as you have different primers. Run them through the chrono and watch the numbers and groups size and POI.

Lowering ES & SD is a simple matter of tuning the load with seating depth changes and powder charge weights, thats it. Powder choice and charge weight is usually where it's at. Your rifle is either in tune or it's not, there's no middle ground here.

Good luck to all.
 
Re: Tightening up ES and SD numbers?

Okay, a misunderstanding. That's fine.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
Lowering ES & SD is a simple matter of tuning the load with seating depth changes and powder charge weights, thats it. </div></div>

I can agree with that part and that is what I was trying to convey to OP.
BB
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: fw707</div><div class="ubbcode-body">Thanks for the info!
I'd like to try some of the Wolf primers but nobody close has them and I don't want to pay the Haz-Mat just to try them out.

</div></div>

Send an e-mail to [email protected].

They can let you know who has them close by.

As for the "hazmat" fee, if you're spending a lot on your regular primers, check out Powder Valley. If I buy two boxes of Wolf Primers from them I've actually paid for the hazmat fee from just the savings over local pricing on US Brand primers.
 
Re: Tightening up ES and SD numbers?

I disagree. But I use the Chrony as one source of load information. Perhaps it is coincidence, but I've never gotten good results with inconsistent velocities in the 500+ yard ranges.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">

While chrono numbers, ES and SD, are important to some, they mean diddly squat to me. I think Chronos are simply incapable of producing numbers that are reliable in such small increments; and that when ES and SD are 'good', I seriously doubt they have a meaningful relationship with what's actually happening on the target.

Greg </div></div>
 
Re: Tightening up ES and SD numbers?

My question is; how do you achieve those single digit ES? Do you expect 100/200/500 cases to have the exact same capacity so that your chronograph will display numbers that make you happy? BB
 
Re: Tightening up ES and SD numbers?

See above.

Some people do <span style="font-weight: bold">everything</span> they can to insure shot to shot consistency. It really is that simple.

I know a Gent who says he spends 3 hours reloading for every hour at the range, and he is NOT a high volume shooter by any means whatsoever. You have to make the decision - perfect rounds vs other uses of your time, talent and money.

If you take the sum total of all advice on this forum, you would basically eat, shit and sleep shooting 24/7.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">My question is; how do you achieve those single digit ES? </div></div>
 
Re: Tightening up ES and SD numbers?

I do my load developement at 600yrds, my targets tell me everything I need to know...I could care less about Chronos, ES & SD's. Proven over and over again in F-Class matches
wink.gif
 
Re: Tightening up ES and SD numbers?

It appears that you're trying to develop your ES and SD from a sample size of 5 or 6 rounds. Your ES doesn't matter that much but just be aware that a SD from an N of less than 10 can have some significant error. I wouldn't get bogged down with the SD number with your sample size anyway. Just due to the math involved with calculating SD, the bigger the sample the more accurate the calculation. FYI, wiki has a good explanation of what Standard Deviation is if you didn't already know what it was.
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Some people do everything they can to insure shot to shot consistency. It really is that simple. </div></div>

Yeah, I know all about it, and that three hours is a conservative statement, in my world, (since I am a hunter) but at least I admit that some of it is in the category of "can't hurt" and another large portion is strictly MOJO.

Like the F Class guy says, when you get right down to it, it is in superior equipment rather than all the anal stuff we do with case prep. Don't get me wrong, I do it, but not for military gear with the factory chambers. You have to know what and where will do some good. Radical statement: All shooting and all rifles are not the same. BB
 
Re: Tightening up ES and SD numbers?

Shooting Chrony only guarantees 99.5% accuracy, or a 10fps error margin for a 2000fps projectile. So if you're shooting a 2800fps load, your chrony is only guaranteed to be within 14fps of the actual velocity. That doesn't make me feel particularly warm and fuzzy about people who claim ES or SD in the single digits, unless they're shooting sample sizes that are quite large.
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Conqueror</div><div class="ubbcode-body">Shooting Chrony only guarantees 99.5% accuracy, or a 10fps error margin for a 2000fps projectile. So if you're shooting a 2800fps load, your chrony is only guaranteed to be within 14fps of the actual velocity. That doesn't make me feel particularly warm and fuzzy about people who claim ES or SD in the single digits, unless they're shooting sample sizes that are quite large. </div></div>

This is the reason I took so long to get a chrony. I feel like some people read the print out of their machine and its gospel. I tried to find how they defined their 99% accuracy (i.e. calibration) but I've not found anything readily available on the subject. Its only a piece of equipment which provides data. Just make sure you use the data appropriately.
 
Re: Tightening up ES and SD numbers?

How would a large sample affect ES?

I agree about accuracy of measuring SD. The single digit values are meaningful in a relative sense - same rifle, same Chrony - one load gives SD of 25, and another 5. The difference is meaningful. 10 vs 5 eh, not so much
smile.gif


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Conqueror</div><div class="ubbcode-body">Shooting Chrony only guarantees 99.5% accuracy, or a 10fps error margin for a 2000fps projectile. So if you're shooting a 2800fps load, your chrony is only guaranteed to be within 14fps of the actual velocity. That doesn't make me feel particularly warm and fuzzy about people who claim ES or SD in the single digits, unless they're shooting sample sizes that are quite large. </div></div>
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Conqueror</div><div class="ubbcode-body">Shooting Chrony only guarantees 99.5% accuracy, or a 10fps error margin for a 2000fps projectile. So if you're shooting a 2800fps load, your chrony is only guaranteed to be within 14fps of the actual velocity. That doesn't make me feel particularly warm and fuzzy about people who claim ES or SD in the single digits, unless they're shooting sample sizes that are quite large. </div></div>

Some of us have given up on Shooting Chrony's and gone to more accurate models. I use the PACT XP Pro and also shoot a minimum of 25 rounds when evaluating the round's "statistics". I don't chronograph until I've worked up a good accurate load "on the target".
 
Re: Tightening up ES and SD numbers?

Another point of view. I shoot high performance stuff and can't afford the luxury of 25 shot samples, from the standpoint of a finite number of accurate rounds through a tube. Anyway, such data only shows you where you were yesterday.
BB
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Cigarcop</div><div class="ubbcode-body">I do my load developement at 600yrds, my targets tell me everything I need to know...I could care less about Chronos, ES & SD's. Proven over and over again in F-Class matches
wink.gif
</div></div>


^^^^this!

As taught at Rifles Only, "believe the bullet". It's readily apparent if a load shoots or not. I quit chasing reloading "ghosts" years ago. I don't do half the crap many do, I use good old decapping dies with expander ball on "cheap" FL dies, have never turned a neck.
My 6XC and 6.5CM both shoot around 1/2 moa at 500....
 
Re: Tightening up ES and SD numbers?

Yesterday is a dandy starting point for figuring out where you are today.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BuzzBoss915</div><div class="ubbcode-body">Anyway, such data only shows you where you were yesterday.
BB </div></div>


RO uses "believe the bullet" for shooting purposes. Not reloading. Implicitly there is an assumption that the rifle and ammo are capable.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">As taught at Rifles Only, "believe the bullet"</div></div>
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jAXDIALATION</div><div class="ubbcode-body">


RO uses "believe the bullet" for shooting purposes. Not reloading. Implicitly there is an assumption that the rifle and ammo are capable.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">As taught at Rifles Only, "believe the bullet"</div></div> </div></div>

If a load shoots 1/2 minute at 500, but the chrono tells me my SD is high I believe the bullet not the numbers-that was my point.
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Deadshot2</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Conqueror</div><div class="ubbcode-body">Shooting Chrony only guarantees 99.5% accuracy, or a 10fps error margin for a 2000fps projectile. So if you're shooting a 2800fps load, your chrony is only guaranteed to be within 14fps of the actual velocity. That doesn't make me feel particularly warm and fuzzy about people who claim ES or SD in the single digits, unless they're shooting sample sizes that are quite large. </div></div>

Some of us have given up on Shooting Chrony's and gone to more accurate models. I use the PACT XP Pro and also shoot a minimum of 25 rounds when evaluating the round's "statistics". I don't chronograph until I've worked up a good accurate load "on the target". </div></div>
I just looked and was not able to even find any technical specifications on the PACT XP Pro. Do you have documentation that it is any more accurate than the Shooting Chrony? It has a lot of other bells and whistles, but I can't find its measurement accuracy rating on their website.
 
Re: Tightening up ES and SD numbers?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Conqueror</div><div class="ubbcode-body">
I just looked and was not able to even find any technical specifications on the PACT XP Pro. Do you have documentation that it is any more accurate than the Shooting Chrony? It has a lot of other bells and whistles, but I can't find its measurement accuracy rating on their website. </div></div>

Just the fact alone that you can shoot strings larger than 10 shots without "writing over" the first shots contributes to accuracy. I can shoot far longer strings, thus getting a far better sample size for SD/ES/MAD than with the Chrony.

That coupled by the fact that my PACT has yet to fail to register a shot versus entire days that the Shooting Chrony won't work at all due to lighting conditions makes it more "accurate". How can something that works so erratically be even close to accurate?
 
Re: Tightening up ES and SD numbers?

No time to read through this whole thread, but if it hasn't been mentioned, the actual powder used can make a difference. My initial load development session for my .260 consisted of using Lapua brass, CCI BR2 primers, Berger 140 Hybrids, and both H4350 and RL-17. I tested 5 loads each for 5 rounds of H4350 and RL-17.

The H4350 shot very well on paper but the ES was terrible, in the 30-50 FPS range. I didn't calculate SD. The RL-17 on the other hand shot well but every load had a VERY low ES, in the 10-15 FPS range.

I stopped load development with 4350 at that point and moved to RL-17 where I was able to obtain a load that was accurate and consistent velocity.
 
Re: Tightening up ES and SD numbers?

I agree with the above, insofar as the propellent used can be a huge contributing factor to consistent numbers. As humans, we want total uniformity, on paper and electronic readouts/measurements. Often, unrealistic.

I (personal opinion) am a little annoyed when somebody can't be bothered to read the thread, but still is compelled to add a comment, but in this case I think it's a worthwhile contribution. No offense, bm11. I hope you are not offended?
BB

PS that's one of the things I like about the Oehler. I can place my screens ten feet apart, if I want and this contributes to accuracy. But, even 4 feet with the proof channel is pretty accurate. (I think)
 
Re: Tightening up ES and SD numbers?

If you concluded RL17 is a better powder than H4350 for the 260 cartridge, there may have been some other variables in play during your testing. 4350 is to 260s what Varget is for 308s

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bm11</div><div class="ubbcode-body">

The H4350 shot very well on paper but the ES was terrible, in the 30-50 FPS range. I didn't calculate SD. The RL-17 on the other hand shot well but every load had a VERY low ES, in the 10-15 FPS range.

I stopped load development with 4350 at that point and moved to RL-17 where I was able to obtain a load that was accurate and consistent velocity. </div></div>
 
You must log in or register to reply here.

Similar threads

Gd33333
SD and ES inconsistencies
Replies
76
Views
1K
secondofangle2
secondofangle2
Max_The_Phoenix
H4350 with br2 and 450 primers + peterson brass
Replies
12
Views
620
DeathBeforeDismount
DeathBeforeDismount
.505gibbs
What contributes to ES and SD beside the obvious?
Replies
12
Views
700
GTOJOSH
GTOJOSH
markl323
ES too high
Replies
115
Views
2K
DeathBeforeDismount
DeathBeforeDismount
B
Chronograph data
Replies
18
Views
354
straightshooter1
straightshooter1
Top Bottom
Back